Name: discovering middle ear anatomy by transcanal endoscopic ear surgery: a dissection manual
Uploaded: 2018-01-11T13:00:00.000+00:00
Duration: 10 min 40 s
Description: Watch this Scientific Journal Video about Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual at JoVE.com

<p class="jove_content">Lo studio presente è stato approvato dal comitato di revisione istituzionale locale (KEK-essere 2016-00887).</p>
<p class="jove_title">1. preparazione del campione</p>
<ol><li>Posizionare un materasso vuoto sul tavolo di dissezione e coprire con una coperta sterile. Porre il campione anatomico in grado chirurgico sul materasso con la testa leggermente ruotata sul lato controlaterale.</li>
	<li>Ritrarre il tragus con un gancio flessibile sul lato controlaterale.</li>
	<li>Coprire il campione con una coperta con parsimonia l'orecchio esterno, proprio come in sala operatoria.<br>Nota: Vedere la <strong>Tabella materiali</strong> per una lista completa delle attrezzature necessarie.</li>
</ol><p class="jove_title">2. operazioni preliminari</p>
<ol><li>Adottare una posizione di seduta o in piedi confortevole e regolare lo schermo di endoscopio. Si tratta di una questione importante per evitare l'indurimento dei muscoli del collo e di conseguenza più veloce esaurimento.</li>
	<li>Eseguire il bilanciamento nel menu macchina fotografica bianco e applicare una goccia di soluzione antinebbia sulla punta dell'endoscopio.</li>
	<li>Tenere gli strumenti chirurgici in mano dominante e l'endoscopio in altra mano.</li>
	<li>Introdurre il 0°, diametro di 3 mm ed endoscopio lunghezza 15cm in EAC. Come prima operazione, pulire l'EAC accuratamente da cerume eventualmente presente utilizzando il tubo di aspirazione. Sciacquare l'EAC con acqua. Tagliare i capelli all'interno di EAC con un paio di piccole forbici per impedire che l'endoscopio si sporchi durante ogni passaggio.</li>
	<li>Una volta pulito l'EAC, ispezionare la membrana timpanica (TM). Identificare:<br>-Malleus con processo breve, manubrio e umbone<br>-Anulus della membrana timpanica<br>-Pars flaccida (membrana di Shrappnel)</li>
</ol><p class="jove_title">3. altezza della falda Tympano-Meatal (TMF)</p>
<p class="jove_content">Nota: Nella chirurgia endoscopica dell'orecchio, il TMF è eseguita leggermente più piccolo e in una forma triangolare. Il motivo è lo spazio limitato all'interno di EAC.</p>
<ol><li>Incidere la pelle EAC superiormente, leggermente anteriore al breve processo di malleus con una falce o un coltello rotondo.</li>
	<li>Estendere l'incisione alla parte superiore posteriore della EAC e prolungare l'incisione al bordo anteriore e inferiore del TM per configurare una falda a forma triangolare.</li>
	<li>Con il coltello rotondo ad angolo di 45°, esporre l'osso ed elevare la pelle fino a raggiungere l'anulus. È importante rispettare rigorosamente l'osso.</li>
	<li>Elevare l'anulus con il coltello rotondo per accedere la cavità tympanic (TC). La mucosa del TC è leggermente più trasparente rispetto alla pelle e viene incisa al livello del tympani di chorda usando un gancio.</li>
	<li>Mobilitare l'anulus inferiormente e anteriormente utilizzando il dissettore Thomassin.</li>
	<li>Identificare superiormente il legamento laterale posteriore del malleus (PLML). Questo legamento rappresenta il limite inferiore dello spazio Prussak. Afferrare il legamento con il forcipe di Hartmann e tirarlo delicatamente anteriormente in direzione l'umbone fino a scoprire il processo breve di malleus.</li>
	<li>Sezionare delicatamente lo spazio Prussak anteriore fino a raggiungere l'inserzione superiore anteriore dell'anulus. Ora identificare:<br>-Anulus<br>-Corda timpano<br>-Malleolar posteriore legamento<br>-Malleolari laterale ligamental piega<br>-Piega ligamental malleolari anteriore<br>-Spazio Prussak</li>
</ol><p class="jove_title">4. distacco di TMF dal manico di Malleus</p>
<ol><li>Dal processo breve di malleus, continuare la dissezione e incidere il periostio della maniglia malleolari verso l'umbone con un dissettore di ago. È importante staccare il TM nell'aereo giusto per evitare perforazioni accidentali.</li>
	<li>Staccare il TM completamente dal manubrio. Un cottonoid asciutto può essere utile, dal momento che facilita l'identificazione del corretto livello e sua dissezione.</li>
	<li>Una volta raggiunto l'umbone, tagliare lo strato fibroso restante del TM utilizzando una micro-forbice.</li>
	<li>Ora posizionare il lembo intero sulla parete anteriore di EAC per consentire il libero accesso alla TC. Identificare:<br>-Strato fibroso della membrana timpanica<br>-Anteriore e superiore dell'annulus<br>-Umbone, manubrio e processo breve malleus<br>-Corda timpano anteriore al malleus</li>
</ol><p class="jove_title">5. esplorazione dell'orecchio centrale</p>
<p class="jove_content">Nota: Questa parte della dissezione aiuta nel riconoscimento e nella prova dell'anatomia dell'orecchio medio. Ogni suddivisione del TC dovrebbe essere esplorato separatamente utilizzando endoscopi 0° e 45°. Alla fine presentare pieghe o aderenze con attenzione dovrebbero essere rimosso.</p>
<ol><li>Epitympanum. Identificare:<br>-Malleus: Collo, processo breve, manubrio e umbone<br>-Incudine: Corpo, processo lungo, processo lenticolare, incudostapedial comune<br>-Diaframma Epitympanic: legamenti malleolari anteriori e laterali, ligamental piega laterale incudomalleolar<br>-Anteriore e posteriore della colonna vertebrale<br>-Corda timpano<br>-Modelli timpanici istmo e ventilazione al antrum<br>-Cochleariform processo<br>-Tensore del timpano muscolo, tendine e canale ossuto<br>-Piega tensore</li>
	<li>Mesotympanum. Identificare:<br>-Stapes: Capitulum, crus anteriore e posteriore, pedana<br>-Tendine del muscolo stapedial<br>-Eminenza piramidale<br>-Osso promontorio<br>-Nervo Jacobson con arteria timpanica inferiore</li>
	<li>Retrotympanum: Se le aderenze sono presenti dovrebbero essere accuratamente rimossi. Cambiando la posizione del chirurgo al lato controlaterale facilita l'accesso al retrotympanum dall'ottica angolato (45°). Identificare:<br>-Recesso facciale<br>-Seno posteriore<br>-Ponticulus<br>-Timpani seno<br>-Subiculum<br>-Eminenza styloid<br>-Seno subtympanic<br>-Osso Fustis<br>-Area concamerata<br>-Nicchia di finestra rotonda con tegmen, pilastro anteriore e posteriore<br>-Membrana rotonda della finestra<br>-Canalicolo Subcochlear<br>-Finiculus</li>
	<li>Hypotympanum<br>-Cellule Hypotympanic<br>-Stimare la localizzazione della JVB se non visibile</li>
	<li>Protympanum. Identificare:<br>-Protiniculus<br>-Interna dell'arteria carotica<br>-Tubo Eustachian (ET)</li>
	<li>Disarticulate giunto incudostapedial e rimuovere incus. Con un curette rimuovere scuto. Identificare:<br>-Segmento timpanico del nervo facciale<br>-Laterale del canale semicircolare<br>-Antrum<br>-COG o cresta trasversa<br>-Tympani di tegmen</li>
	<li>Tagliare il tendine del muscolo tensore del timpano e rimuovere il malleus. Identificare:<br>-Epitympanum anteriore<br>-Ganglio genicolato</li>
</ol>

<ol>
	<li>Presutti, L., Marchioni, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Endoscopic Ear Surgery</em>. , (2015).</li><li>Weiss, M. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgery+for+recurrent+and+residual+cholesteatoma.">Surgery for recurrent and residual cholesteatoma.</a> <em style='font-style: italic'>Laryngoscope</em>. <b>102</b>, 145-151 (1992).</li><li>Pickett, B. P., Cail, W. S., Lambert, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sinus+tympani:+anatomic+considerations,+computed+tomography,+and+a+discussion+of+the+retrofacial+approach+for+removal+of+disease.">Sinus tympani: anatomic considerations, computed tomography, and a discussion of the retrofacial approach for removal of disease.</a> <em style='font-style: italic'>Am J Otol</em>. <b>16</b>, 541-550 (1995).</li><li>James, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscope+or+microscope-guided+pediatric+tympanoplasty?+Comparison+of+grafting+technique+and+outcome.">Endoscope or microscope-guided pediatric tympanoplasty? Comparison of grafting technique and outcome.</a> <em style='font-style: italic'>Laryngoscope</em>. , (2017).</li><li>Tarabichi, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+management+of+limited+attic+cholesteatoma.">Endoscopic management of limited attic cholesteatoma.</a> <em style='font-style: italic'>Laryngoscope</em>. <b>114</b> (7), 1157-1162 (2004).</li><li>Bonali, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+variants+of+the+retro-+and+hypotympanum:+an+endoscopic+anatomical+study.">The variants of the retro- and hypotympanum: an endoscopic anatomical study.</a> <em style='font-style: italic'>Eur Arch Otorhinolaryngol</em>. , (2017).</li><li>Bennett, M. L., Zhang, D., Labadie, R. F., Noble, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+Middle+Ear+Visualization+With+Endoscopy+and+Microscopy.">Comparison of Middle Ear Visualization With Endoscopy and Microscopy.</a> <em style='font-style: italic'>Otol Neurotol</em>. <b>37</b> (4), 362-366 (2016).</li><li>Anschuetz, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Ovine+Model+for+Exclusive+Endoscopic+Ear+Surgery.">An Ovine Model for Exclusive Endoscopic Ear Surgery.</a> <em style='font-style: italic'>JAMA Otolaryngol Head Neck Surg</em>. <b>143</b> (3), 247-252 (2017).</li><li>Wang, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+costs+and+quality+of+operative+training+for+residents+in+tympanoplasty+type+I.">The costs and quality of operative training for residents in tympanoplasty type I.</a> <em style='font-style: italic'>Acta Otolaryngol</em>. <b>129</b>, 512-514 (2009).</li><li>Dedmon, M. M., Kozin, E. D., Lee, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+Temporal+Bone+Model+for+Transcanal+Endoscopic+Ear+Surgery.">Development of a Temporal Bone Model for Transcanal Endoscopic Ear Surgery.</a> <em style='font-style: italic'>Otolaryngol Head Neck Surg</em>. <b>153</b> (4), 613-615 (2015).</li><li>Barber, S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D-printed+pediatric+endoscopic+ear+surgery+simulator+for+surgical+training.">3D-printed pediatric endoscopic ear surgery simulator for surgical training.</a> <em style='font-style: italic'>Int J Pediatr Otorhinolaryngol</em>. <b>90</b>, 113-118 (2016).</li></ol>

<p class="jove_content">Gli autori non dichiarano alcun conflitto di interessi. LA tiene una borsa di ricerca dalla Fondazione Bangerter-Rhyner, Berna, Svizzera e da Karl Storz GmbH, Tuttlingen, Germania. I finanziatori non avevano alcun ruolo nel disegno dello studio, raccolta dati e analisi, decisione di pubblicare o preparazione del manoscritto.</p>

<p class="jove_content">Il manuale di dissezione proposto è utile per eseguire una completa dissezione anatomica dell'orecchio medio. Esporre una conoscenza approfondita dell'anatomia dell'orecchio medio è un prerequisito fondamentale per qualsiasi intervento chirurgico dell'orecchio medio. La dissezione cadaverica permette la gestione della telecamera e gli strumenti chirurgici in EAC di formazione. Per un novizio in SEO, il coordinamento tra l'occhio e lo strumento, nonché la corretta gestione dell'endoscopio (nessuna piegatura, destreggiandosi tra strutture anatomiche importanti come gli ossicini in uno spazio limitato e l'immagine bidimensionale) sono critici passaggi per iniziare con questa tecnica chirurgica di emergenti.</p>
<p class="jove_content">Il limite principale di questo modello rispetto alla situazione reale chirurgica è la mancanza di sanguinamento. Questo vale per qualsiasi modello di dissezione cadaverica. Recentemente, Dedmond <em>et al</em>. descrisse un modello dell'osso temporale, dove lo spurgo è stato simulato durante l'elevazione della TMF. Questo modello può in realtà essere una buona opzione per i chirurghi avanzate già utilizzato per SEO. Nella nostra esperienza, la familiarizzazione iniziale con EES dovrebbe essere più semplice possibile, poiché la manipolazione degli strumenti è già un compito impegnativo. La dissezione cadaverica è considerata il gold standard per la formazione chirurgica. Tuttavia, è soggetto a costi elevati e norme etiche. In confronto, modelli sintetici o animali possono superare questi problemi<sup class="xref">8</sup><sup>,</sup><sup class="xref">11</sup>. Tuttavia, in modelli sintetici la sensazione tattile per i tessuti è difficile e la risoluzione di stampa 3D non è ancora in grado di fornire tutti i dati di che un campione anatomico possibile. Al contrario, il modello animale fornisce proprietà eccellente del tessuto ma ha una diversa anatomia. Possiamo considerare il modello cadaverico l'unico modello adatto per l'insegnamento anatomico, mentre modelli sintetici e animali forniscono alternative a buon mercato per addestramento chirurgico.</p>
<p class="jove_content">Rispetto alla tecnica microscopica per la dissezione dell'orecchio medio, l'endoscopio consente l'osservazione e la preparazione delle strutture dell'orecchio medio delicato attraverso un orifizio naturale, EAC. Quindi, nessun osso deve essere rimosso per scopi di accesso e dell'orecchio medio possono essere studiato nel suo stato naturale. Inoltre, l'endoscopio consente una molto stretta osservazione di qualsiasi struttura anatomica e quindi anche ingrandimento senza perdere illuminazione. Naturalmente, l'approccio endoscopico non insegna mastoidectomia, che può essere eseguita dallo stesso campione dopo dissezione endoscopica. La tecnica endoscopica per chirurgia dell'orecchio si sta diffondendo a livello internazionale e di conseguenza aumenterà la necessità di formazione chirurgica adatta.</p>

<p class="jove_content">L'orecchio medio è situato nel centro dell'osso temporale e reca un'anatomia altamente complessa. Le strutture più contigue sono il nervo facciale (FN), la coclea (CO), la catena ossiculary (OC), il bulbo della vena giugulare (JVB) e l'arteria carotica interna (AIC). La schisi dell'orecchio centrale è anatomicamente diviso in cinque parti: il epitympanum si trova superiormente ed è collegato da antrum al sistema delle cellule di aria mastoid (Mac); il retrotympanum posteriore è un sistema di ponti ossei e seni più o meno superficiali; inferiormente si trova il hypotympanum; anteriormente è il protympanum con il suo collegamento al tubo di Eustachian; e al centro, si trova il mesotympanum<sup class="xref">1</sup>.</p>
<p class="jove_content">L'accesso fisiologico attraverso il canale uditivo esterno (EAC) è stretta. Di conseguenza, l'approccio chirurgico standard per l'orecchio medio richiede un'incisione retroauricular e la foratura dei Mac. Questi tipi di interventi sono eseguiti utilizzando un microscopio operatorio. Sua introduzione è stata una pietra miliare nell'ambulatorio otologic, poiché ha permesso il trattamento delle strutture microscopiche dell'orecchio medio. Tuttavia, il microscopio ha una vista dritta forzata e alcune aree, soprattutto il tympani di seno, sono difficilmente accessibili. Questo comporta il rischio di malattia residua specialmente durante cholesteatoma chirurgia<sup class="xref">2</sup><sup>,</sup><sup class="xref">3</sup>. Inoltre, devono essere rimossi semplicemente per scopi di accesso tessuti sani del EAC, MACS e dell'orecchio medio. Questo si estende non solo il tempo di funzionamento, ma anche gli account per altre morbilità chirurgica e una guarigione prolungata tempo<sup class="xref">4</sup>.</p>
<p class="jove_content">Gli avanzamenti recenti hanno portato all'introduzione dell'endoscopio come un potente strumento per chirurgia dell'orecchio. L'endoscopio è stato prima utilizzato per assistere il chirurgo convenzionalmente per visualizzare le aree nascoste dell'orecchio medio. Perfezionamenti tecnici e chirurgici ha permesso l'introduzione dell'endoscopio come il principale strumento<sup class="xref">5</sup>di funzionamento. I principali vantaggi dell'endoscopio sono le vedute panoramiche e grandangolare dell'orecchio medio. Per esempio, l'altrimenti nascosti retrò - e hypotympanum possono accedervi utilizzando un approccio esclusivo transcanal endoscopico senza un canaloplastica<sup class="xref">6</sup>. Uno studio recente ha mostrato una visibilità superiore di tutti i comparti dell'orecchio centrale utilizzando l'endoscopio rispetto alla tecnica microscopica<sup class="xref">7</sup>. Ulteriormente, l'uso di endoscopi angolati (30° e 45°) migliora la visibilità e consente una dissezione con una vista delle zone più nascoste dell'orecchio medio.</p>
<p class="jove_content">Tuttavia, la chirurgia endoscopica dell'orecchio (EES) è una tecnica chirurgica con una sola mano, come la lancetta dei secondi in genere detiene l'endoscopio. Questo problema e lo spazio ristretto all'interno di EAC richiedono formazione migliorare le abilità del chirurgo per applicare in modo sicuro la tecnica nei pazienti. In generale, il gold standard per addestramento chirurgico è considerato la dissezione cadaverica. In caso di mancata disponibilità di esemplari cadaverici o problemi etici locali, un modello animale per la formazione di chirurgia endoscopica dell'orecchio è stato recentemente descritto<sup class="xref">8</sup>. Training chirurgico è considerato un fattore importante nella formazione dei tirocinanti in una tecnica novella<sup class="xref">9</sup>.</p>
<p class="jove_content">Nonostante l'importanza dell'addestramento chirurgico, una descrizione concisa delle considerazioni importanti su come eseguire la dissezione cadaverica è ancora carente nella letteratura. Lo scopo di questo articolo è di descrivere la metodologia di esclusivamente la dissezione endoscopica cadaverico dell'orecchio medio. Inoltre, ci proponiamo di fornire una guida completa all'anatomia endoscopica dell'orecchio medio.</p>

<table><tbody><tr><td>Endoscopes: 3mm diameter, 15cm length, 0&amp;deg; and 45&amp;deg;</td><td>Karl Storz</td><td></td><td></td></tr><tr><td>Otologic dissectors, round knifes, hooks, curette, microscissors (Bellucci) and microforceps (Hartmann)</td><td>Karl Storz</td><td></td><td></td></tr><tr><td>Straight and curved suction tubes</td><td>Karl Storz</td><td></td><td></td></tr><tr><td>Flexible hook</td><td></td><td></td><td></td></tr><tr><td>Scissors</td><td></td><td></td><td></td></tr><tr><td>Video Equipment&lt;br/&gt; - HD-scree&lt;br/&gt; - 3-CCD camera&lt;br/&gt; - Xenon light source</td><td>Karl Storz</td><td></td><td></td></tr><tr><td>Cadaveric Head</td><td>-</td><td></td><td></td></tr><tr><td>Vacuum matress</td><td></td><td></td><td></td></tr><tr><td>Aspirator</td><td></td><td></td><td></td></tr><tr><td>Consumables&lt;br/&gt; - Water to rinse&lt;br/&gt; - Antifog solution&lt;br/&gt; - Cotton pads&lt;br/&gt; - Cottonoid pledges&lt;br/&gt; - Gown&lt;br/&gt; - Gloves&lt;br/&gt; - Mask</td><td></td><td></td><td></td></tr></tbody></table>

discovering middle ear anatomy by transcanal endoscopic ear surgery: a dissection manual

<p class="jove_content">L'orecchio medio è situato nel centro dell'osso temporale e reca un'anatomia altamente complessa. L'approccio di transcanal esclusivamente endoscopica recentemente introdotto per l'orecchio medio è una tecnica mini-invasiva con parsimonia l'osso e mucosa dell'osso mastoide, dal momento che l'orecchio medio è accessibile attraverso il canale uditivo esterno. Questo metodo emergente presenta parecchi vantaggi sopra gli approcci tradizionali (microscopici) all'orecchio medio come la vista grandangolare dell'anatomia, la possibilità di avvicinarsi e di ingrandire piccole strutture e la possibilità di guardarsi intorno il angolo mediante endoscopi angolati.</p>
<p class="jove_content">Il metodo di dissezione cadaverica presentato qui è costituito da una panoramica sui requisiti tecnici e una descrizione precisa di un protocollo di passo dopo passo per scoprire l'anatomia dell'orecchio medio. Ogni passo e la struttura anatomica è descritto con attenzione al fine di fornire una guida completa alla anatomia endoscopica dell'orecchio. A nostro parere, questo è particolarmente importante per i principianti nella chirurgia endoscopica dell'orecchio quanto fornisce approfondite conoscenze anatomiche e possono migliorare le abilità chirurgica.</p>

<p class="jove_content" fo:keep-together.within-page="1">Abbiamo sezionato un totale di cinque tutta la testa e 12 provini di osso temporale (n = 22 lati) utilizzando le istruzioni descritte. Le diverse regioni del TC sono state documentate fotograficamente e ulteriormente analizzate. Tutte le regioni sono state esplorate utilizzando endoscopi 0° e 45°. Abbiamo condotto un'esplorazione completa di tutte le regioni anatomiche e identificato tutti i menzionati limiti anatomici.</p>
<p class="jove_content" fo:keep-together.within-page="1">Le strutture anatomiche sono illustrate secondo lo stato di avanzamento della dissezione. <strong class="xfig">La figura 1</strong> illustra lo spazio Prussak e i legamenti malleolari, mentre <strong class="xfig">nella figura 2</strong> viene illustrato l'anatomia dopo l'elevazione di TMF completa. La vista grandangolare permette la visualizzazione del meso - e hypotympanum, nonché parti della epi-, retro-e protympanum. Nella <strong class="xfig">Figura 3</strong>, il retrotympanum superiore è indicato come appare in un endoscopio di 45 °, mentre il chirurgo è in piedi sul lato opposto del tavolo. <strong class="xfig">La figura 4</strong> illustra in dettaglio il protympanum con un ICA deiscente. Dopo la rimozione della atticotomy OC e transcanal il epitympanum viene controllato fino al canale semicircolare laterale e il antrum come mostrato nella <strong class="xfig">Figura 5</strong>.</p>
<p class="jove_content" fo:keep-together.within-page="1">Nessun esemplare necessaria canaloplastica per eseguire la completa esplorazione della cavità timpanica. L'identificazione delle strutture anatomiche era possibile in tutti gli esemplari utilizzando l'ambito di 0° e 45°. Tuttavia, l'esplorazione completa del retrotympanum, specialmente l'incavo facciale ed i timpani del seno, non era possibile nel 27% dei casi (n = 6), poiché queste baie ossute erano troppo profonde per essere completamente esplorata.</p>
<p class="jove_content" fo:keep-together.within-page="1"><img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56390/56390fig1.jpg"><br><strong class="xfig">Figura 1</strong>. Orecchio sinistro, endoscopio 0°: visualizzazione dello spazio Prussak e le pieghe ligamental circostanti del malleus. TM: membrana timpanica, un: anulus, u: umbone, sp: breve processo di malleus, amf: malleolari anteriore piega, lmf: malleolari laterali fold, plm: legamento posteriore del malleus, ct: corda del timpano, *: Prussak spazio <a href="//cloudflare.jove.com/files/ftp_upload/56390/56390fig1large.jpg" target="_blank">Clicca qui per visualizzare una versione più grande di questo figura.</a></p>
<p class="jove_content" fo:keep-together.within-page="1"><img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56390/56390fig2.jpg"><br><strong class="xfig">Nella figura 2</strong>. Orecchio sinistro, endoscopio 0°: visualizzazione della cavità timpanica dopo l'elevazione della falda tympano-meatal. Il meso - e hypotympanum, nonché parti della epi-, retro - e protympanum sono visualizzati. PR: promontorio, GV: nervo di Jacobson, hy: hypotympanum, fi: finiculus, sst: subtympanicus del seno, se: styloid Eminenza, pe: Eminenza piramidale, st: tendine stapediali, isj: incudostapedial congiunta, fn: nervo facciale, u: umbone, m: manubrium, sp: processo breve, n: collo di il malleus, ttm: muscolo tensore del timpano, ttf: tensore del timpano piega, ica. Dell'arteria carotica interna <a href="//cloudflare.jove.com/files/ftp_upload/56390/56390fig2large.jpg" target="_blank">Clicca qui per visualizzare una versione più grande di questa figura.</a></p>
<p class="jove_content" fo:keep-together.within-page="1"><img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56390/56390fig3.jpg"><br><strong class="xfig">Nella figura 3</strong>. A destra dell'orecchio, endoscopio di 45°, posizione controlaterale del chirurgo: il retrotympanum superiore è illustrata utilizzando un endoscopio angolato. FN: nervo facciale, s: stapes, st: tendine stapediali, ps: posteriore del seno, fp: pedana, po: ponticulus, pe: Eminenza piramidale, sit: tympani di seno, sub, subiculum, se: styloid Eminenza, sst: del seno subtympanicus, ap: pilastro anteriore, teg: tegmen, pp: posteriore pilastro, rw: finestra rotonda, fu: fustis, tu: subcochlear tunnel <a href="//cloudflare.jove.com/files/ftp_upload/56390/56390fig3large.jpg" target="_blank">Clicca qui per visualizzare una versione più grande di questa figura.</a></p>
<p class="jove_content" fo:keep-together.within-page="1"><img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56390/56390fig4.jpg"><br><strong class="xfig">Nella figura 4</strong>. Orecchio sinistro, endoscopio 45°: dettagli della protympanum. Si noti l'arteria carotica deiscente. et: tubo di Eustachian, ica: arteria carotide interna, pro: protiniculus, co: coclea, ttm: muscolo tensore del timpano <a href="//cloudflare.jove.com/files/ftp_upload/56390/56390fig4large.jpg" target="_blank">Clicca qui per visualizzare una versione più grande di questa figura.</a></p>
<p class="jove_content" fo:keep-together.within-page="1"><img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56390/56390fig5.jpg"><br><strong class="xfig">Nella figura 5</strong>. Orecchio sinistro, endoscopio 0°: dopo rimozione del incus e malleolo e curettage dello scuto, un'ampia panoramica del tympani di tegmen e l'antro è illustrata qui. Nota il canale semicircolare laterale e muscolo tensore del timpano in una riga con l'incrocio del nervo facciale. TEG: tegmen, cog: COG o cresta trasversa, gg: ganglio genicolato, cp: cochleariform processo, ttm: muscolo tensore del timpano, lsc: canale semicircolare laterale, fn: segmento timpanico del nervo facciale, s: stapes, co: coclea, ica: arteria carotica interna <a href="//cloudflare.jove.com/files/ftp_upload/56390/56390fig5large.jpg" style="font-size: 14px;" target="_blank">per favore Clicca qui per visualizzare una versione più grande di questa figura.</a></p>

Watch this Scientific Journal Video about Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual at JoVE.com

Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual

<p class="jove_content">Lo scopo di questo articolo è di descrivere la metodologia di esclusivamente la dissezione endoscopica cadaverico dell'orecchio medio. Inoltre, ci proponiamo di fornire una guida completa all'anatomia endoscopica dell'orecchio medio.</p>

Alla scoperta di anatomia dell'orecchio medio da ambulatorio endoscopico orecchio Transcanal: un manuale di dissezione

The middle ear is located in the center of the temporal bone and bears a highly complex anatomy. The recently introduced exclusively endoscopic transcanal ...

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64.2K Views.  University of Bern. Lo scopo di questo articolo è di descrivere la metodologia di esclusivamente la dissezione endoscopica cadaverico dell'orecchio medio. Inoltre, ci proponiamo di fornire una guida completa all'anatomia endoscopica dell'orecchio medio.

Video: Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual

Cell Structure

<h4>Background</h4>
<p>Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, multicellular organisms like elephants and giant redwood trees. In the mid 19<sup>th</sup> century, the Cell Theory was proposed to define a cell, which states:</p>
<ul>
	<li>Every living organism is made up of one or more cells.</li>
	<li>The cells are the functional units of all organisms.</li>
	<li>All cells arise from preexisting cells.</li>
</ul>
<p>All cells share common features such as having a plasma membrane, a cytoplasm, DNA, and ribosomes. A plasma membrane is a phospholipid bilayer that surrounds the cell. This thin and fluid layer around the cells serves to isolate the cell&#8217;s contents from its environment and regulates the material exchange with its environment, while also facilitating interactions with other cells. Inside the plasma membrane, the cell is filled with a gel-like fluid called cytoplasm that contains organic molecules, salts, and other materials that are vital for the cell&#8217;s functions. Therefore, biochemical reactions that support life, which are known as metabolic processes, take place inside the cytoplasm. The types of metabolic processes that a cell can execute depend on its genetic information. All cells use DNA as the genetic material, which is the hereditary blueprint to construct cellular structures and products. Finally, all cells use ribosomes to synthesize their protein products.</p>
<p>There are two types of cells based on their genetic material location: prokaryotic, which means &#8220;before nucleus&#8221;, and eukaryotic, which means &#8220;true nucleus&#8221;. Therefore, while both types of organisms have DNA, prokaryotes like bacteria have nucleoids, or &#8220;nucleus-like&#8221; components instead of a nucleus, whereas eukaryotes possess true, membrane-bound nuclei to contain their DNA. Moreover, prokaryotes are relatively small, around 0.1&#8211;5.0 micrometers (&#181;m), in comparison to eukaryotes that can typically range from 10-100 &#181;m in size. The small size of prokaryotes allows quick and effortless distribution of materials within the cell and execution of metabolic processes, as well as swift removal of waste or other products from the cell. Hence, eukaryotic cells possess specialized structures known as organelles, such as mitochondria or Golgi apparatus, to enable the execution of vital functions.</p>
<h4>The Eukaryotic Cell</h4>
<p>The eukaryotic cell is a shared derived trait of all eukaryotes, meaning that it had a single origin that has since been inherited by all eukaryotes. The earliest eukaryotic cells are seen in fossils about 2.4 billion years ago, and are recognizable because they are larger than prokaryotic cells<sup>1</sup>. The origin of this cell type resulted from an endosymbiotic event in which one amoeba-like cell engulfed a micrococcal bacteria and formed a stable coexistence<sup>2</sup>. The engulfed bacteria evolved into the first energy-producing organelles, mitochondria, which are the aerobic metabolism organelles in the cell. Mitochondria have their own separate genome and are similar in size to prokaryotes. They contain two layers of membranes that enclose two distinct compartments. Some of the reactions that break down high-energy biomolecules occur in the inner compartment, whereas the outer compartment houses the reactions that capture the energy released from these compounds into adenosine triphosphate (ATP) molecules to be used as the energy currency of the cell.</p>
<p>Nuclei and mitochondria are not the only shared structures of eukaryotic cells. Other ubiquitous eukaryotic organelles are the smooth and rough endoplasmic reticulum (ER), Golgi apparatus, lysosomes and vacuoles. Endoplasmic reticulum simply means &#8220;network inside the plasma&#8221; and as its name indicates it is a large network of membranes inside the cell, especially around the nucleus. Parts of the rough ER extend from the nuclear membrane and are distinguished from the smooth ER by their rough appearance due to numerous ribosomes on their surface. Rough ER is the site for protein synthesis, such as the proteins that are embedded in the plasma membrane or the proteins that are secreted from the cell. In contrast, smooth ER produces lipid-based products but also contains enzymes to detoxify harmful chemicals. Hence liver cells contain abundant smooth ER. Also, muscle cells contain significant amounts of smooth ER because of the calcium-storing function of this organelle, which is essential for muscle contraction. The Golgi apparatus sorts, modifies, and packages cellular products inside vesicles, which fuse with the plasma membrane to release the products. Some of the proteins that are produced in the rough ER are intracellular digestive enzymes. These enzymes are packed in the Golgi apparatus into special vesicles called lysosomes. The major function of the lysosomes is to digest the food particles engulfed by the cell as well as old cell parts. Vacuoles are sacs of cell membrane that serve as storage units within cells. They may serve to store water to regulate the cell&#8217;s water content as well as store metabolic products or even poisonous molecules, depending on the cell type and the organism.</p>
<h4>Kingdom-specific Organelles</h4>
<p>Eukaryotic cells also developed distinct organelles, specific for each kingdom. For instance, kingdom Plantae and Animalia are both eukaryotic, however the organelles of plant and animal cells differ in key ways that allow them to carry out their lives as producers and consumers, respectively. Terrestrial plants need to grow tall and have rigid stems to hold leaves, which they use for photosynthesis. They also need to be able to retain water taken up by roots. Their cells reflect these specific needs. Unlike animal cells, plant cells have chloroplasts, which are used for photosynthesis and often contain the green pigment chlorophyll. Additionally, they are surrounded by cell walls, which are rigid outer layers made of cellulose to support growth and water retention. Because they need to store large amounts of water to maintain the water pressure in the cell, they have larger vacuoles than animal cells. In addition, plant cells also have another type of specialized storage organelles called plastids, which contain pigments as well as photosynthetic products such as starch. These differences are noticeable and distinguish plant cells from animal cells: plant cells generally have a regular, rectangular shape due to their rigid cell walls, while animal cells are rounded and more irregular.</p>
<h4>Microscopy</h4>
<p>Some cells, such as frog oocytes, are large enough to be seen with the naked eye, yet most cells cannot be seen without any visual aid. Therefore, scientists use microscopy techniques to study cell structures and distinguish cell types from one another. While microscopes are able to magnify objects that are difficult or impossible to be see with the human eye, most tissues naturally lack pigmentation. Therefore, solutions have been created that can selectively stain cells based on their molecular composition. This allows researchers to distinguish between organelles in a cell, tissue types in a plant stem, and fat layers in animals, just to name a few examples. Methylene blue dye stains nucleic acids of dead cells, binding to negatively charged DNA. Safranin solution is another biological dye that stains cell nuclei red. Cells only need to be in the staining solutions for a short period of time, and can be mounted immediately following the staining step. The commonly used mounting techniques are wet mount and oil immersion. A wet mount is created by collecting a sample and putting it on a glass slide with liquid between the slide and the coverslip. Cell samples are suspended in liquids like water or glycerol. Glycerol is better to use with live cultures, because it prevents the proliferation of bacteria<sup>3</sup>. Immersion oil can be added on top of the coverslip to improve viewing of the sample at high magnification. This is accomplished because the oil has the same refractive index as glass, which means that it allows light to pass through it as well as glass would. The glass-air interface scatters light more than oil or glass, so the clarity of the image is affected when samples are mounted &#8220;dry&#8221;, or without oil. Once the cells are stained and mounted, they are ready to be studied under the microscope.</p>
<p>There are various microscopy techniques from electron scanning technology that has allowed researchers to view objects on an atomic level to fluorescent live cell imaging that allows real-time monitoring of the movement of molecules within individual cells<sup>4</sup>. Bright-field microscopy is the simplest microscopy technique, requiring only a halogen source light, a condenser lens to focus the light, an ocular lens to view the image, and an objective lens to magnify the image. With any microscopy technique, it is important to understand the parts of a microscope before using one. In general, compound microscopes used for bright-field imaging have an eyepiece at the top of the scope, which is attached to the head and objectives. The eyepiece has a magnification of 10X, and objective lenses are set to a particular magnification in a range of 4X-100X. There are between three and five objectives on a standard microscope. The objectives point down to the stage, which is where a specimen is placed for viewing. The stage often has mechanical parts and stage clips to hold a slide and move it around while viewing. An aperture is a hole in the stage for light to pass through. This light is controlled by an adjustable condenser lens above an illuminator, or light source. To control the zoom of the stage for the object being viewed, microscopes feature coarse and fine focus adjustment knobs. The coarse focus knob moves on a larger scale than the fine focus, but they are on the same axis. The fine focus is useful when the object on the stage has been brought close to the objectives. It is important not to let the objective lens touch the object on the stage, as it can scratch the lens. Objects should always be first viewed on the lowest magnification objective and clearly focused before switching to higher magnification objectives.</p>
<p>Microscopy is an important tool for many aspects of the medical field including research, diagnosis, and treatment. This has the application of using nanotechnology in medicine, as a new treatment method in place of a more invasive surgery<sup>5</sup>. Surgeons also make use of microscopes, some of which have been modified to be mounted on a surgeon&#8217;s head and are operated with foot pedals. These are of much lower magnification than even the light microscopes used today, but they facilitate the safe execution of delicate procedures, such as optical and neurosurgery.</p>
<h4>References</h4>
<ol class="references">
	<li><strong>Bengtson S, Rasmussen B, Ivarsson M, Muhling J, Broman C, Marone F, Stampanoni M, Bekker A.</strong> Fungus-like mycelial fossils in 2.4-billion-year-old vesicular basalt. <em>Nature Ecology &#38; Evolution. </em>2017, Vol. 1, Article number: 0141.</li>
	<li><strong>Vellai T, Vida G.</strong> The origin of eukaryotes: the difference between prokaryotic and eukaryotic cells. <em>Proc. R. Soc. Lond. B. </em>1999, Vol. 266, 1571-1577.</li>
	<li><strong>Gouet V, Roger G, Fonty C, Andre P.</strong> Effects of glycerol on the growth, adhesion, and cellulolytic activity of rumen cellulolytic bacteria and anaerobic fungi. <em>Current Microbiology. </em>24, 1992, Vol. 4, 197-201.</li>
	<li><strong>Cognet L, Leduc C, Lounis B.</strong> Advances in live-cell single-particle tracking and dynamic super-resolution imaging. <em>Curr Opin Chem Biol. </em>2014, Jun; 20:78-85.</li>
	<li><strong>Asiyanbola B, Soboyejo W.</strong> For the surgeon: an introduction to nanotechnology. <em>J Surg Educ. </em>2008, Vol. 65, 2 (155-61).</li>
</ol>

Cell Structure: Visualizing Onion and Human Cells - Concept

Struttura cellulare

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Didattica

JoVE Lab Manual

Biologia

Fondamenti

Scientific Measurement and Lab Skills

Two-Dimensional Graphs, Curve Fitting, and Standard Deviation - Procedure

Misure scientifiche e competenze di laboratorio

Source: Smaa Koraym at Johns Hopkins University, MD, USA

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	Error can be introduced in any experiment, even ...

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Extraction

Extraction: Liquid-Liquid and Acid-Base Extraction - Procedure

Estrazione

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Cellulose RecoveryExpand
	Extraction and filtration can ...

Lab Techniques

<p>Source: Smaa Koraym at Johns Hopkins University, MD, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse=""><strong>Determining the Density of an Egg</strong><button class="expand">Expand</button>
	<p>Density is a measure of how compact a substance or object is, and it is calculated as mass divided by volume. When a dense object is placed in a liquid with a lower density, the object sinks; when the object is less dense than the liquid, it floats. When the densities are the same, the object will be suspended in the liquid. In this experiment, we&#39;ll determine the density of an egg by creating a solution with the same density. We&#39;ll measure the density of the salt solution using different volume measurement glassware and determine which is the most accurate.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-1">
		<div class="lab-step">To begin, wear the appropriate personal protective equipment, including close-toed shoes, long pants, long-sleeved shirt, lab coat, chemical splash goggles, and gloves.</div>
		</li>
		<li data-sub-note-item="1-2">
		<div class="lab-step">Measure the mass of the egg. Set a weigh boat on the balance and tare it. Carefully set the egg in the weigh boat while you record the mass in your notebook.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Prepare the salt solution that will be used to suspend your egg. Use the 600-mL beaker and fill it 3/4 of the way full with deionized water.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Gently place your egg in the beaker, and then add about one teaspoon of NaCl into the water. Stir the solution gently until the NaCl dissolves. Continue to add NaCl until the egg floats just below the surface.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Use different glassware to measure the volume of the salt solution. Weigh the 50-mL graduated cylinder on the top loading balance and record the mass. Then, measure 20 mL of your salt solution and record the volume in your notebook. <strong>Note: </strong>Place a blank sheet of paper behind the graduated cylinder to read the volume more clearly. Always view the measurement at eye level and measure the volume from the bottom of the meniscus. The lines on the graduated cylinder are 0.2 mL apart, meaning that you can read the volume to the hundredths place.
		<h4><b>Table 1: Measuring Mass</b></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td style="text-align: center;"><strong>Container</strong></td>
					<td style="text-align: center;"><strong>Mass of empty container (g)</strong></td>
					<td style="text-align: center;"><strong>Mass of full containter (g)</strong></td>
					<td style="text-align: center;"><strong>Mass of solution (g)</strong></td>
					<td style="text-align: center;"><strong>Percent error</strong></td>
				</tr>
				<tr>
					<td>50-mL graduated cylinder</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>10-mL volumetric pipette</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>50-mL beaker</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td>20-mL volumetric flask</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www.jove.com/CDNSource/lm/labs/41/Table_1._Measuring_Mass.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Weigh the filled graduated cylinder and record the mass in your notebook. Then, pour the salt solution back into the 600-mL beaker.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Use the volumetric pipette to measure volume. First, weigh the empty 50-mL beaker and record the mass in your notebook. Then, carefully measure 10 mL of the salt solution using the volumetric pipette and dispense the salt solution into the beaker.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Measure another 10 mL and add it to the beaker. Weigh the filled beaker and record the mass in your notebook. Then, empty, rinse, and dry the beaker.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Use the volumetric flask to measure volume. Weigh the empty 20-mL volumetric flask and record the mass. Then, carefully fill the flask with the salt solution to just below the 20-mL fill mark. Do not fill it all the way. Use an eyedropper to finish filling the flask so that the bottom of the meniscus just touches the fill line on the neck of the flask. Then, weigh the full flask and record the weight.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Lastly, use the 50-mL beaker to measure volume. Weigh the empty beaker, then fill the beaker with salt solution to the 20-mL line and weigh the full beaker. Record the masses in your notebook.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Measure the displacement of the egg when it is submerged in the salt solution. First, remove the egg and look at the level of the salt solution in the 600-mL beaker. <strong>Note:</strong> If it is not at a marked line, add deionized water to the solution so that the meniscus is at a readable volume and record the volume.&#160;
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Measurements</strong></td>
					<td><strong>Salt solution using 20-mL volumetric flask&#160;</strong></td>
					<td><strong>Egg</strong></td>
				</tr>
				<tr>
					<td>Mass (g)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Displacement of water (cm)</td>
					<td style="text-align: center;">-</td>
					<td></td>
				</tr>
				<tr>
					<td>Inner diameter of 600-mL beaker (cm)</td>
					<td style="text-align: center;">-</td>
					<td></td>
				</tr>
				<tr>
					<td>Volume (cm&#179;)</td>
					<td style="text-align: center;">-</td>
					<td></td>
				</tr>
				<tr>
					<td>Volume (mL)</td>
					<td style="text-align: center;">20</td>
					<td></td>
				</tr>
				<tr>
					<td>Density (g/mL)</td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<strong><a href="https://www.jove.com/CDNSource/lm/labs/41/Table_2._Measuring_Density.xlsx" target="_blank">Click Here to download Table 2</a> </strong></div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Gently place the egg in the beaker.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Use a ruler to measure the new height of the solution level and record the height. Then, place the ruler across the top of the beaker to measure the inner diameter.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Calculate the new volume from these measurements. Subtract the initial volume to obtain the displacement of the egg (volume).</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">To clean up from the experiment, return the egg to your instructor and pour the salt solution down the sink. Rinse all used glassware with tap water and set them out to dry. Finally, return the sodium chloride to your instructor.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse=""><strong>Results</strong><button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">Calculate the mass of the solution in each of the different volumetric glassware by subtracting the empty glassware mass from the full glassware mass.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Keep track of uncertainty in your measurement by using significant figures. For example, when we look at the graduated cylinder measurement, the weight of the empty container is 90.92, and the weight of the full container is 111.59. The weight measurements have significant figures to the hundredths place, so it is important that significant figures are maintained throughout our calculations. Thus, the mass of the 20-mL salt solution is 20.67 g.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">The 50-mL beaker weighed 28.65 g when it was empty and 47.96 g when it contained 20 mL of salt solution. Therefore, the mass of 20 mL of the salt solution is 19.31 g.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Repeat the calculation to obtain the mass of 20 mL of salt solution that was measured using the 10-mL pipette and the 200-mL volumetric flask.<b> Note:</b> Generally speaking, volumetric measurements are more accurate when using a volumetric flask.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Look at the accuracy of the other methods compared to the volumetric flask in terms of percent error. Percent error is calculated by subtracting the theoretical value from the experimental value, then dividing by the theoretical value times 100.
		<ul>
			<li><img src="https://www.jove.com/CDNSource/lm/labs/41/41_Procedure_1b.jpg" /></li>
		</ul>
		</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Use the volumetric flask measurement as the theoretical value to determine the percent error for the other volume measurement methods. As expected, the volume measurement that uses the markings on the beaker is the least accurate.<strong> Note: </strong>We also know this because the known density of pure water is 1 g/mL. Thus, 20 mL of pure water weighs 20 g. The density of the salt solution must be higher than 20 g since salt was added to the water.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">Calculate the density of the salt solution using the volumetric flask measurement. Divide the mass of the solution by the volume of the solution. Thus, the density of the salt solution is 1.053 g/mL.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Compare the calculated density of the salt solution to the density of the egg. The volume calculated using the displacement of water in a beaker was found to be 61.14 cm<sup>3</sup> or 61.14 mL. The weight of the egg was measured to be 60.15 g, so its density is 0.9838 g/mL. The disparity between the density of the egg and the density of the salt solution arises from error introduced in both calculations, primarily due to volume measurement readings.</div>
		</li>
	</ul>
	</li>
</ol>

Accuracy, Precision, Uncertainty, and Significant Figures - Procedure

Tecniche di laboratorio

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Determining the Density of an EggExpand
	Density is a measure of how compact a substance or ...

Eusociality and Division of Labor

<ol class="note-items"><li data-note-item="1" data-parent-collapse="">Simulating Eusocial and Solitary Behavior
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="1-1"><div class="lab-step">Note: In this simulation, you will portray either a eusocial or solitary animal. The goal of this simulation is to maximize your fitness by reproducing as many offspring as possible during the allotted five minutes. To do this, you must forage for resources and reproduce within the constraints of your assigned role.
</div></li><li data-sub-note-item="1-2"><div class="lab-step">Assuming a class size of 10, 4 individuals should form the solitary, or the carpenter bee group, and the remaining 6 students should form the eusocial, or the honeybee group. Note: The eusocial honeybee group will include one queen, one drone, and four workers. The queen and the drone will reproduce and protect the resources, while the workers will forage and steal resources. The solitary carpenter bee students must perform all of the tasks in this activity, with the exception of reproduction, by themselves.
</div></li><li data-sub-note-item="1-3"><div class="lab-step">Store your resources for reproduction in the nest bowl provided by your instructor. These resources are represented by assorted beans that can be collected by foraging in the environment buckets or by stealing from other nests.
</div></li><li data-sub-note-item="1-4"><div class="lab-step">The blue cups are male and the red cups are female, and they will be used to produce offspring. This is done by combining all four bean types in one red or blue cup to symbolize the resources needed to reproduce, and then stacking one completed cup inside a cup of the opposite color that also contains one of each bean type, to simulate a mating that produces two-cup offspring, one from each parent.
</div></li><li data-sub-note-item="1-5"><div class="lab-step">To reproduce, the solitary students will need to seek out another solitary student with an opposite-colored cup. Conversely, the eusocial queen and drone always reproduce with each other. HYPOTHESES: The hypotheses for this lab activity are based on the possible benefits of eusocial groups over solitary individuals. The alternate hypothesis could be that one group, either eusocial or solitary, will have an advantage over the other, given the ecological constraints, and this will be reflected in the number of offspring per capita. The null hypothesis might be that there will be advantage conferred by either of the strategies.
</div></li><li data-sub-note-item="1-6"><div class="lab-step">If you are a worker in the honeybee group or a solitary student in the carpenter bee group, walk to the other side of the room to search through the rice on the foraging side of the room for one bean and bring the bean back to your bowl on the nest side of the room. Note: Even though this activity has a 5-minute time limit, running is not permitted. 
</div></li><li data-sub-note-item="1-7"><div class="lab-step">If a solitary student is not present at a neighboring bowl, you can try to steal one bean at a time, using a cup to scoop up the bean without touching the bean or the bowl with anything but the cup. You must immediately stop trying to steal if the solitary student makes it back to their bowl before you finish stealing. Note: Neighbors cannot steal from eusocial nests because the queen and drone do not leave their nest.
</div></li><li data-sub-note-item="1-8"><div class="lab-step">You can create offspring at any time during the activity. Remember to label each cup that is contributed to an offspring with your name to keep track of your reproduction.  Note: Eusocial groups produce two offspring for their group every time they reproduce, while solitary students produce only one offspring per reproductive coupling.
</div></li></ul></li><li data-note-item="2" data-parent-collapse="">Results
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="2-1"><div class="lab-step">If you were a solitary carpenter bee, record the number of offspring you produced in the appropriate row of the table. <a href="https://www.jove.com/CDNSource/lm/labs/36/Table_1_Eusociality_and_division_of_labor.xlsx" style="display:block;margin:20px;" target="_blank">Click Here to download Table 1</a>
</div></li><li data-sub-note-item="2-2"><div class="lab-step">If you were a part of the eusocial honeybee group, record the number of offspring produced by your queen and drone.
</div></li><li data-sub-note-item="2-3"><div class="lab-step">To calculate the fitness for a solitary carpenter bee student, simply count the number of offspring that the student produced.
</div></li><li data-sub-note-item="2-4"><div class="lab-step">To calculate the fitness for a eusocial honeybee student, divide the number of offspring produced by the queen and drone by the number of members in the group, in this case 6, to get a per-student fitness value.
</div></li><li data-sub-note-item="2-5"><div class="lab-step">When each student has calculated their respective fitness value, calculate the average number of offspring produced for each social category and plot these as a bar graph. <a href="https://www.jove.com/CDNSource/lm/labs/36/Table_2_Eusociality_and_division_of_labor.xlsx" style="display:block;margin:20px;" target="_blank">Click Here to download Table 2</a>
</div></li><li data-sub-note-item="2-6"><div class="lab-step">Next, use Hamilton&#39;s equation to analyze the data. To do this, set r equal to the degree of relatedness, B to the class average eusocial fitness, and C to the class average solitary fitness.  r * B > C
</div></li><li data-sub-note-item="2-7"><div class="lab-step">Use these results to determine if altruistic behavior should persist in your eusocial honeybee group. Discuss the variables in Hamilton&#39;s equation that may contribute to this observation. Consider circumstances under which you would expect to see different results. 
</div></li></ul></li></ol>

Eusocialità e divisione del lavoro

Simulating Eusocial and Solitary Behavior
ExpandNote: In this simulation, you will portray either a eusocial or solitary animal. The goal of this ...

Ecologia

Community Diversity

<ol class="note-items"><li data-note-item="1" data-parent-collapse="">Measuring Biodiversity in Areas with Different Disturbance Regimes
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="1-1"><div class="lab-step">NOTE: In this experiment, you will compare the biodiversity in a less disturbed area against a more highly disturbed area. HYPOTHESES: The experimental hypothesis could be that a less disturbed area will contain a greater diversity of species than a highly disturbed area. The null hypothesis could be that there will be no difference in diversity between less disturbed and highly disturbed areas. 
</div></li><li data-sub-note-item="1-2"><div class="lab-step">To begin, divide into groups of 2-4 and collect a hula hoop, ball, measuring tape, set of printed tables, 10 utility flags, and an ID guide from the front of the class.
</div></li><li data-sub-note-item="1-3"><div class="lab-step">Additionally, collect a shovel and 10 collecting bottles for the soil sampling exercise.
</div></li><li data-sub-note-item="1-4"><div class="lab-step">Once in the field, your instructor will show you the two habitats you will study - choose one habitat to begin.
</div></li><li data-sub-note-item="1-5"><div class="lab-step">Place one flag in each of four corners to form a rectangular sampling area.
</div></li><li data-sub-note-item="1-6"><div class="lab-step">Measure the length and width of the sampling area in meters, and then multiply the two numbers to determine the area.
</div></li><li data-sub-note-item="1-7"><div class="lab-step">Standing in the middle of the sampling area, throw a tennis ball into the air, and then Mark the location where it lands with a flag.
</div></li><li data-sub-note-item="1-8"><div class="lab-step">Repeat this random throw four additional times to determine all five of your random sampling points.
</div></li><li data-sub-note-item="1-9"><div class="lab-step">Keeping your flag at the center, place a hula hoop around it. The area within the hula hoop is a quadrat.
</div></li><li data-sub-note-item="1-10"><div class="lab-step">Identify all of the different species in the quadrat and record them as species A, B, and so on in Table 1, provided by your instructor.
</div></li><li data-sub-note-item="1-11"><div class="lab-step">Once all of the plants have been recorded, use a shovel to collect one cup of soil from each of the sites and put the samples bottles labeled with your names and the site name and quadrat number.
</div></li><li data-sub-note-item="1-12"><div class="lab-step">Repeat the plant identification and soil sampling for the remaining four quadrats in the first habitat, recording your observations in Table 1.
</div></li><li data-sub-note-item="1-13"><div class="lab-step">Once you have completed recording in the first habitat, move on to the second field, again marking out a rectangular sampling area.
</div></li><li data-sub-note-item="1-14"><div class="lab-step">Repeat the random placement of quadrats using the tennis ball, and then record the species present in each quadrat in Table 2. 
</div></li><li data-sub-note-item="1-15"><div class="lab-step">Finally, collect one cup of soil from each of the disturbed habitats&#39; quadrats, for a total of five cups from the disturbed and five cups from the undisturbed habitats.
</div></li></ul></li><li data-note-item="2" data-parent-collapse="">Measuring Biodiversity Along a Transect
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="2-1"><div class="lab-step">NOTE: The next part of the study will test for edge effects, or a change along a gradient from where one ecosystem type meets another to the core habitat of the ecosystem. HYPOTHESES: The experimental hypothesis is that there will be a greater diversity of species closer to the edge of the ecosystem than in the center, or core, of the ecosystem. The null hypothesis is that there is no change in diversity along the transect from edge to core habitat.
</div></li><li data-sub-note-item="2-2"><div class="lab-step">Place a flag at the perimeter of the field where it meets another habitat, like a forest or parking lot.
</div></li><li data-sub-note-item="2-3"><div class="lab-step">Extend a tape measure towards the center of the field, perpendicular to the edge of the field. This will be the transect.
</div></li><li data-sub-note-item="2-4"><div class="lab-step">Place a flag at the zero meter of the transect (the edge of the other habitat) then place additional flags at 10 m, 20 m, 30 m, and 40 m into the core of the habitat for a total of five flagged locations.
</div></li><li data-sub-note-item="2-5"><div class="lab-step">Starting at the 0 m point along the transect, place the hula hoop at the flagged location. Record the species present in the quadrat in Table 4.
</div></li><li data-sub-note-item="2-6"><div class="lab-step">Now repeat the quadrant placement and species recording at the 10 m, 20 m, 30 m, and 40 m marks.
</div></li><li data-sub-note-item="2-7"><div class="lab-step">Next, place two more transects from different starting points at the perimeter of the field extending into the core area.
</div></li><li data-sub-note-item="2-8"><div class="lab-step">Mark the 10-meter points along these transects, and again use these as markers to place quadrats. Record the species found in each of these quadrats in Table 4.
</div></li></ul></li><li data-note-item="3" data-parent-collapse="">Processing the Soil Samples
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="3-1"><div class="lab-step">HYPOTHESES: The experimental hypothesis is that the two landscapes under different disturbance regimes will differ in their soil composition and pH. The null hypothesis is that there will be no difference in the soil composition or pH between the two sites. 
</div></li><li data-sub-note-item="3-2"><div class="lab-step">To begin, remove soil from one bottle of the first site sampled and fill the pH color compartment of the soil sample kit to the soil fill line.
</div></li><li data-sub-note-item="3-3"><div class="lab-step">Pour the pH test capsule into the test chamber, then fill the capsule with distilled water until it reaches the water fill line.
</div></li><li data-sub-note-item="3-4"><div class="lab-step">Place the cap on the compartment and shake it.
</div></li><li data-sub-note-item="3-5"><div class="lab-step">Allow the color to develop for about a minute, and then compare the soil to the color chart to determine the pH.
</div></li><li data-sub-note-item="3-6"><div class="lab-step">Repeat the pH analysis for the second sampled site, filling out Table 3 for the recorded pH.
</div></li><li data-sub-note-item="3-7"><div class="lab-step">To process the soil samples for nitrogen, phosphorus, and potassium, remove 20 mL of soil from the bottle of the first site sampled.
</div></li><li data-sub-note-item="3-8"><div class="lab-step">Place the soil in a clean container with 100 mL of distilled water.
</div></li><li data-sub-note-item="3-9"><div class="lab-step">Repeat this process for the second site, labeling each container, and then allow them to sit for one hour.
</div></li><li data-sub-note-item="3-10"><div class="lab-step">After one hour, use a dropper to fill each of the nitrogen, phosphorous, and potassium comparators to the fill line with solution from the first sampled site.
</div></li><li data-sub-note-item="3-11"><div class="lab-step">Add the appropriate capsule to each of the comparators for each chemical test.
</div></li><li data-sub-note-item="3-12"><div class="lab-step">Cap and shake the comparators thoroughly, and then compare the solution in the test chamber to the color chart, recording the results as the appropriate number on the scale into Table 3.
</div></li><li data-sub-note-item="3-13"><div class="lab-step">Repeat the nitrogen, phosphorous, and potassium tests for each of the sampled sites. NOTE: Rinse the comparator thoroughly between samples
</div></li></ul></li><li data-note-item="4" data-parent-collapse="">Results
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="4-1"><div class="lab-step">To calculate the Shannon-Weiner Diversity for each of the observed sites, first open a new Excel spreadsheet.
</div></li><li data-sub-note-item="4-2"><div class="lab-step">Label cell A1 'species name', and cell B1 'total count'.
</div></li><li data-sub-note-item="4-3"><div class="lab-step">Starting from the second row and in column A, fill in the sheet for each species found in the first site, using the data recorded in Table 1.
</div></li><li data-sub-note-item="4-4"><div class="lab-step">Calculate the total number of each species found in the entire sampling effort and record this in the B column of the Excel spreadsheet.
</div></li><li data-sub-note-item="4-5"><div class="lab-step">Now, label cell G1 'total count of all species', and in cell H1, write a formula, or highlight the appropriate cells to sum all of the count values entered in column B: = SUM(B2: BX)
</div></li><li data-sub-note-item="4-6"><div class="lab-step">Label cell C1 'proportion of each species' and in cell C2, type the formula for the proportion of the total of each species at the site. = B2/H$1
</div></li><li data-sub-note-item="4-7"><div class="lab-step">Drag this formula down for each row of data represented in column B.
</div></li><li data-sub-note-item="4-8"><div class="lab-step">Label cell D1 'natural log proportion of species' and in cell D2, type the formula for the natural log of the proportion of species at the site. =LN(C2)
</div></li><li data-sub-note-item="4-9"><div class="lab-step">Drag this formula down for each row of data represented in column C.
</div></li><li data-sub-note-item="4-10"><div class="lab-step">Add the formula into cell E1 for the proportion of species multiplied by the natural log of the proportion of species: ps* ln ps
</div></li><li data-sub-note-item="4-11"><div class="lab-step">In cell E2, type the formula multiplying the proportion of species by the natural log of the proportion of species at each site, and then drag this formula down for each row of data represented in column D. = C2 * D2 
</div></li><li data-sub-note-item="4-12"><div class="lab-step">Label cell G2 as 'sum of ps * ln ps', and then, in cell H2, type a formula summing all of the values in column E. = SUM(E3 - EX) 
</div></li><li data-sub-note-item="4-13"><div class="lab-step">Label cell G3 'Shannon-Weiner Index', and in cell H3, enter the formula for the Shannon-Weiner Diversity Index. = (EXP - 1 * H2) NOTE: This is the calculated Shannon-Weiner Diversity Index for the first sampled site, and will be used for comparison between the two sites.
</div></li><li data-sub-note-item="4-14"><div class="lab-step">Repeat the data analysis in a new sheet using the data collected for the second site, which was recorded in Table 2. NOTE: Areas with greater index values are considered to have greater species diversity. Note whether you see differences between your sites.
</div></li><li data-sub-note-item="4-15"><div class="lab-step">Repeat the Shannon-Weiner Diversity calculations using a total count of all the species at each distance along the transect, then create a table of all of these values in a new Excel sheet.
</div></li><li data-sub-note-item="4-16"><div class="lab-step">Click on the Data tab in Excel, and then on the 'Data Analysis' button.
</div></li><li data-sub-note-item="4-17"><div class="lab-step">Select 'Regression' and click 'Okay'.
</div></li><li data-sub-note-item="4-18"><div class="lab-step">For the Input Y Range, highlight the Shannon-Weiner Diversity values, and for the Input X range, highlight the distance values.
</div></li><li data-sub-note-item="4-19"><div class="lab-step">Select an output location for the regression results and click 'Okay'.
</div></li><li data-sub-note-item="4-20"><div class="lab-step">Check the P-value box in the intercept row to see if there is a significant correlation between distance from edge to core habitat and biodiversity. NOTE: A value of less than 0.05 rejects the null hypothesis of no change in diversity along the transect, while a value greater than 0.05 does not reject the null hypothesis.
</div></li><li data-sub-note-item="4-21"><div class="lab-step">Next, to perform t-tests for determining soil composition differences between sites, open a new Excel spreadsheet.
</div></li><li data-sub-note-item="4-22"><div class="lab-step">In cell A1, type 'Site 1:pH', and in cell B1, type 'Site 2:pH'.
</div></li><li data-sub-note-item="4-23"><div class="lab-step">Fill in cells A2 through A6 and cells B2 through B6 with the soil pH collected in the disturbed and undisturbed sites, respectively.
</div></li><li data-sub-note-item="4-24"><div class="lab-step">Click the Data tab in Excel and then select 'Data Analysis'.
</div></li><li data-sub-note-item="4-25"><div class="lab-step">Now scroll down and select 't-Test: Two-Sample Assuming Equal Variances' and select 'Okay'.
</div></li><li data-sub-note-item="4-26"><div class="lab-step">Click the drop down next to Variable 1 Range and highlight cells A2 through A6 in the spreadsheet, then click the dropdown next to Variable 2 Range and highlight cells B2 through B6 in the spreadsheet.
</div></li><li data-sub-note-item="4-27"><div class="lab-step">In the box for hypothesized mean difference, type zero as our null hypothesis. This means that there is no difference between the two disturbance regimes.
</div></li><li data-sub-note-item="4-28"><div class="lab-step">Leave the Labels box unchecked and set the alpha value to 0.05.
</div></li><li data-sub-note-item="4-29"><div class="lab-step">Select 'Output Range', and in the box, click an empty space in the spreadsheet.
</div></li><li data-sub-note-item="4-30"><div class="lab-step">Click 'Okay'. A table of t-Test results should be outputted in the spreadsheet.
</div></li><li data-sub-note-item="4-31"><div class="lab-step">The relevant data are the means for each of the sites and the alpha value. If this second value is less than our alpha value of 0.05, we can reject the null hypothesis that there is no difference in pH between the two sites, and the hypothesis that disturbed versus undisturbed sites differ in their pH value would gain support. If this value is greater than 0.05, however, we may not reject our null hypothesis.
</div></li><li data-sub-note-item="4-32"><div class="lab-step">Repeat this analysis for each of the other three soil variables, creating a new spreadsheet for each of the phosphorus, potassium, and nitrogen elements. 
</div></li><li data-sub-note-item="4-33"><div class="lab-step">Note whether your pH and nutrient level results were different in each condition, and discuss with your group how this might affect the community and diversity in the different sites.
</div></li></ul></li></ol>

Community Diversity: Measuring Biodiversity in Different Areas - Procedure

Diversità della comunità

Measuring Biodiversity in Areas with Different Disturbance Regimes
ExpandNOTE: In this experiment, you will compare the biodiversity in a less disturbed ...

Genetics of Organisms

<ol class="note-items"><li data-note-item="1" data-parent-collapse="">REF and WEF Fly Genetics
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="1-1"><div class="lab-step">NOTE: At your station, you should have four vials of flies. They will be labeled as male or female. They will also be labeled with the notation REF for red-eyed flies or WEF for white-eyed flies. The female vial should also be labeled virgin as these flies should be unmated for the purpose of this experiment.
</div></li><li data-sub-note-item="1-2"><div class="lab-step">Make sure you have around five flies in each vial. NOTE: You will perform crosses using these flies to determine if red or white eyes is dominant and if the trait is sex-linked. You should also have two fly anesthesia wands, a paint brush, magnifying glass, fly anesthetic, some empty fly vials, and a sheet of white paper.
</div></li><li data-sub-note-item="1-3"><div class="lab-step">Draw a line in the middle of the paper to make a male side and a female side.
</div></li><li data-sub-note-item="1-4"><div class="lab-step">Dip the fly anesthesia wand into the solution and insert it into the red-eyed female vial until the flies stop moving.
</div></li><li data-sub-note-item="1-5"><div class="lab-step">Then, dip the same wand into the white-eyed male vial until these flies are also anesthetized.
</div></li><li data-sub-note-item="1-6"><div class="lab-step">Tap the flies from the two vials onto the sheet - Females on one side and males on the other.
</div></li><li data-sub-note-item="1-7"><div class="lab-step">Check to make sure that all the flies from the female vial are female and likewise, confirm that the male flies are male.  NOTE: Males are slightly smaller and have a darker solid pigment on the end of their abdomen. Females are larger and have stripes rather than a solid spot.
</div></li><li data-sub-note-item="1-8"><div class="lab-step">If there are any male flies in the female vial, obtain a new vial as these females likely have sperm from males from their own strain and are unusable.
</div></li><li data-sub-note-item="1-9"><div class="lab-step">Now, move the five red-eyed females and five white-eyed males into a new vial using the paintbrush.
</div></li><li data-sub-note-item="1-10"><div class="lab-step">Label this vial to indicate that this is a cross between red-eyed females and white-eyed males. HYPOTHESES: Use Punnett squares to formulate hypotheses for this experiment. Consider what you will see in a few days if the white allele is dominant and there is no effect of parental sex. What if red is dominant? Under the potential offspring genotype in each box, write the expected phenotype.
</div></li><li data-sub-note-item="1-11"><div class="lab-step">To set up the reverse cross, again dip the fly anesthesia wand into the solution and insert it this time into the white-eyed female vial and then the red-eyed male vial until all the flies have stopped moving.
</div></li><li data-sub-note-item="1-12"><div class="lab-step">Tap the flies onto a sheet of white paper and check to make sure that all the flies from the female vial are female and likewise with the male flies.
</div></li><li data-sub-note-item="1-13"><div class="lab-step">Now, move the five white-eyed females and five red-eyed males into a new vial using the paintbrush.
</div></li><li data-sub-note-item="1-14"><div class="lab-step">Label this vial to indicate that this is a cross between white-eyed females and red-eyed males.
</div></li><li data-sub-note-item="1-15"><div class="lab-step">Finally, place the two tubes containing the new crosses into a rack for incubation at room temperature. NOTE: After about three days, larvae should be moving around in the vial.
</div></li><li data-sub-note-item="1-16"><div class="lab-step">Remove the 10 adult flies and dispose of them into the morgue tube containing 70% ethanol.
</div></li><li data-sub-note-item="1-17"><div class="lab-step">Now, put the tubes back in the rack and let the larvae mature until they reach the adult stage in up to two weeks.
</div></li><li data-sub-note-item="1-18"><div class="lab-step">Once all of the larvae from these crosses have matured to adulthood, anesthetize the flies in one of the tubes using the wand.
</div></li><li data-sub-note-item="1-19"><div class="lab-step">Then, on a piece of white paper, sort the flies by sex and phenotype and then record these data.
</div></li><li data-sub-note-item="1-20"><div class="lab-step">Now, repeat this process and tally the sexes and phenotypes for the second cross (steps 1 &#8211; 18).
</div></li><li data-sub-note-item="1-21"><div class="lab-step">Finally, once you have counted all of your flies, dispose of them in the morgue vial.
</div></li></ul></li><li data-note-item="2" data-parent-collapse="">Results
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="2-1"><div class="lab-step">To begin investigating your results, first compare the data you collected with the hypothesis you made using the Punnett squares.
</div></li><li data-sub-note-item="2-2"><div class="lab-step">Did your data match the simple Punnett square hypothesis where red or white is dominant and there is no effect of sex? Compare your data with other lab groups.
</div></li><li data-sub-note-item="2-3"><div class="lab-step">If your data does not match what your Punnett squares predicted, does this indicate that the gene may be sex-linked?
</div></li><li data-sub-note-item="2-4"><div class="lab-step">If the red gene were dominant and sex-linked, when we cross red-eyed females with white-eyed males, all of the offspring would have red eyes. Assuming all of the females were homozygous for the color allele, does this match your data for the first cross?
</div></li><li data-sub-note-item="2-5"><div class="lab-step">If white were dominant and the gene were sex-linked, we would see the exact opposite. So all of the flies would have white eyes. From your data, can you conclude from your first cross whether red or white is dominant?
</div></li><li data-sub-note-item="2-6"><div class="lab-step">When the reciprocal cross of white-eyed females and red-eyed males is performed, if the red phenotype is dominant, all of the females would be red and all of the males would be white. This would also confirm that the gene is specifically x-linked because white-eyed females could then only be produced in crosses with white-eyed males. Did your second cross produce any white-eyed females?
</div></li><li data-sub-note-item="2-7"><div class="lab-step">Finally, if the gene were x-linked and white was dominant, crossing white-eyed females with red-eyed males would result in all of the offspring having white eyes. Does this hypothesis fit with your second cross?
</div></li><li data-sub-note-item="2-8"><div class="lab-step">Look over your data and conclude which of the hypotheses best fits the patterns you found in your crosses. If your data does not fit with any of these, hypothesize why this might be the case.
</div></li></ul></li></ol>

Genetics of Organisms: REF and WEF Fly Genetics - Procedure

Genetica degli organismi

REF and WEF Fly Genetics
ExpandNOTE: At your station, you should have four vials of flies. They will be labeled as male or female. They will also be ...

Genetica

Evolutionary Relationships

<ol class="note-items"><li data-note-item="1" data-parent-collapse="">Forming an Evolutionary Hypothesis
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="1-1"><div class="lab-step">NOTE: A cladogram is an important tool for forming an evolutionary hypothesis. A cladogram is a tree-shaped chart used to depict the hypothetical genealogical relationships between species. The tips or leaves of the chart represent specific species and the branches of the tree are different lengths. The different lengths represent the degree of change between each of the species. The common ancestor of all of the species that a specific line branches from is located at a node, where the branches intersect. Species that share a node are called a sister group.
</div></li><li data-sub-note-item="1-2"><div class="lab-step">To begin, look at the provided blank cladogram and make a hypothesis about where the assigned animals should be placed on the tree. If a blank cladogram has not been provided please <a target="_blank" href="/files/ftp_upload/10562/Blank_Cladogram.png">download one here</a>.
</div></li><li data-sub-note-item="1-3"><div class="lab-step">Next, observe the image of the fossilized animal.
</div></li><li data-sub-note-item="1-4"><div class="lab-step">Using the morphology, or physical characteristics, of the fossil, make a hypothesis about where on your cladogram it should be placed. Add a new line or mark to indicate your proposed position for the fossil.
</div></li></ul></li><li data-note-item="2" data-parent-collapse="">Comparing Gene Sequences Using BLAST
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="2-1"><div class="lab-step">NOTE: Historically, cladograms have been constructed through the comparison of morphology. Now, genetic sequences can also be compared between species of interest to construct cladograms. DNA sequences are not usually preserved in fossils, so for this lab you will use the BLAST database to compare the DNA sequences of living species that are closely related to the fossil to thousands of other living species.
</div></li><li data-sub-note-item="2-2"><div class="lab-step">Before beginning this lab, your instructor will have downloaded the three preserved gene sequences to a folder on your desktop.
</div></li><li data-sub-note-item="2-3"><div class="lab-step">Navigate to the BLAST homepage, which the instructor should have left open in your browser, and click on Saved Strategies from the menu at the top of the page.
</div></li><li data-sub-note-item="2-4"><div class="lab-step">Click Open on the Evolutionary_Relationships_Gene1.txt file.
</div></li><li data-sub-note-item="2-5"><div class="lab-step">Then, click View to go to the Standard Nucleotide BLAST search page. You should be able to see the DNA sequence in the Query Sequence box at the top-right of the screen.
</div></li><li data-sub-note-item="2-6"><div class="lab-step">Scroll to the bottom of the screen and click the BLAST button. Note: It will take a few moments to process and analyze the data. 
</div></li><li data-sub-note-item="2-7"><div class="lab-step">When the data has been processed, a graphic summary will appear.  NOTE: Your query sequence is represented by the blue line at the top of the box. Each of the lines below the blue line represents another sequence in the BLAST database that matches your query. The length and location of these bars represent where and how much of the sequence match up to the query. The color of the bar represents its score, or how identical the sequence is to the query. Below the graphic summary is the Sequences producing significant alignments list, which contains descriptions of the DNA sequences retrieved from the database that most closely align with the query sentence. These are listed in descending order, from the most similar at the top to the least similar at the bottom. On the right, there are several statistics on how closely related each database sequence is to the experimental sequence. The higher the Max, Total, Query Coverage, and Identity scores are, the more similar the query and retrieved sequences are to each other. Similarly, the lower the E value number, the less likely the sequences match was found by random chance and more significantly the alignment is accurate. An E value of 0 indicates a highly significant match.
</div></li><li data-sub-note-item="2-8"><div class="lab-step">Click on the name of the description of the most similar alignment listed. This will take you further down the page to the exact DNA sequence alignment between the retrieved sequence and the query sequence.
</div></li><li data-sub-note-item="2-9"><div class="lab-step">Click on the Sequence ID number. This will open a new tab with more specific information on the retrieved gene sequence.
</div></li><li data-sub-note-item="2-10"><div class="lab-step">Identify and record the scientific and common names of the organism, which should be listed next to Source.
</div></li><li data-sub-note-item="2-11"><div class="lab-step">Identify and record the protein that the gene codes for, which should be listed next to Definition.
</div></li><li data-sub-note-item="2-12"><div class="lab-step">Close the tab and hit Back to return to the Sequences producing significant alignments list.
</div></li><li data-sub-note-item="2-13"><div class="lab-step">Then, repeat steps 7 &#8211; 9 for the next most similar sequences.
</div></li><li data-sub-note-item="2-14"><div class="lab-step">After collecting several species names, return to the Sequences producing significant alignments list and click Select: All to check all of the boxes next to the names of each listed alignment sequence.
</div></li><li data-sub-note-item="2-15"><div class="lab-step">Click on Distance of tree results to create a phylogram based on the similarity of all of the BLAST result gene sequences to the query gene sequence.  Note: Your query fossil relative sequence will be highlighted in yellow.
</div></li><li data-sub-note-item="2-16"><div class="lab-step">Record your sequence&#8217;s location in relation to the other taxon groups shown in the tree.
</div></li><li data-sub-note-item="2-17"><div class="lab-step">Finally, return to the Saved Strategies tab and upload the next saved gene sequence.
</div></li><li data-sub-note-item="2-18"><div class="lab-step">Query the remaining two fossil relative DNA sequences as previously demonstrated (steps 1 &#8211; 16).
</div></li></ul></li><li data-note-item="3" data-parent-collapse="">Data Analysis
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="3-1"><div class="lab-step">Based on your gene sequence results, come up with a second hypothesis about where your fossil specimen fit in the original cladogram.
</div></li><li data-sub-note-item="3-2"><div class="lab-step">Compare this placement with your first hypothesis.
</div></li><li data-sub-note-item="3-3"><div class="lab-step">Compare your tree with your classmates&#8217;. If any of your classmates put the fossil on a different branch, ask them how they came to that decision.
</div></li></ul></li></ol>

Evolutionary Relationships: Using BLAST to Test Evolutionary Hypotheses - Procedure

Relazioni evolutive

Forming an Evolutionary Hypothesis
ExpandNOTE: A cladogram is an important tool for forming an evolutionary hypothesis. A cladogram is a tree-shaped chart ...

Evoluzione

Microbial and Fungal Diversity

<ol class="note-items"><li data-note-item="1" data-parent-collapse="">Examining Microbial Colony Structures
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="1-1"><div class="lab-step">To begin, collect your allocated culture plates and then remove the Parafilm and lid from one of them.
</div></li><li data-sub-note-item="1-2"><div class="lab-step">Place the uncovered plate under a dissecting microscope and then observe the individual communities within each quadrant of the plate.
</div></li><li data-sub-note-item="1-3"><div class="lab-step">As the colonies are identified, fill out the observed colony properties in the appropriate column in the table.  <a href="https://www.jove.com/CDNSource/lm/labs/28/Table_1_Microbial_diversity.xlsx" style="display:block;margin:20px;" target="__blank">Click Here to download Table 1</a>
</div></li><li data-sub-note-item="1-4"><div class="lab-step">Then, repeat the observations for each of the other two bacterial species.
</div></li><li data-sub-note-item="1-5"><div class="lab-step">To perform Gram staining of your three bacterial species, first label the ends of three microscope slides with the initials of each bacteria species, your initials, and the date. HYPOTHESES: In this experiment, the experimental hypothesis might be that it is possible to elucidate different bacterial species and shapes using Gram staining, and that Gram-positive bacteria will stain purple with crystal violet whereas Gram-negative bacteria will appear pink due to the safranin counterstain. The null hypothesis could be that all of the bacterial types will retain both stains equally, and staining will not help elucidate their species or shape.
</div></li><li data-sub-note-item="1-6"><div class="lab-step">To begin the first stain, attach a clip to the slide for ease of handling. For each bacterial smear, remember to be sure to use a cleaned and flame-sterilized inoculating loop.
</div></li><li data-sub-note-item="1-7"><div class="lab-step">Place two loopfuls of sterile distilled water onto the center of the slide.
</div></li><li data-sub-note-item="1-8"><div class="lab-step">After sterilizing the loop again, cool the loop by touching an uninoculated portion of the agar several times.
</div></li><li data-sub-note-item="1-9"><div class="lab-step">Then, remove a small amount of culture from an isolated colony and mix it with the water on the slide.
</div></li><li data-sub-note-item="1-10"><div class="lab-step">Allow the slide to dry at room temperature and heat-fix the smear by quickly passing it through a flame.
</div></li><li data-sub-note-item="1-11"><div class="lab-step">Once dry, pipette several drops of crystal violet onto the slide and let it sit for two to three minutes.
</div></li><li data-sub-note-item="1-12"><div class="lab-step">Carefully rinse the slide with distilled water by aiming the direct flow towards the top of the slide, allowing the water to gently flow down. Do not aim the water flow directly at the smear.
</div></li><li data-sub-note-item="1-13"><div class="lab-step">Next, cover the slide with Gram&#39;s iodine, leave it to sit again for two minutes, and then gently rinse with distilled water.
</div></li><li data-sub-note-item="1-14"><div class="lab-step">Decolorize the slide with 95% ethanol until stain no longer washes away.
</div></li><li data-sub-note-item="1-15"><div class="lab-step">Immediately, rinse the slide with distilled water. This will limit over-decolorizing.
</div></li><li data-sub-note-item="1-16"><div class="lab-step">Then, add several drops of safranin counterstain and leave for 30 s. This will stain any Gram-negative cells present.
</div></li><li data-sub-note-item="1-17"><div class="lab-step">Gently rinse the slide with distilled water and blot dry with absorbent paper.
</div></li><li data-sub-note-item="1-18"><div class="lab-step">After staining the other two slides in the same manner (steps 6 &#8211; 17), observe each with a microscope.
</div></li><li data-sub-note-item="1-19"><div class="lab-step">Use a low power objective first to make coarse adjustments. When you find an ideal section, move on to the higher magnifications.
</div></li><li data-sub-note-item="1-20"><div class="lab-step">After further imaging and adjusting the smear with a medium power objective, add immersion oil directly to the smear. NOTE: The oil is needed for high power objectives that will provide the best micrographs.
</div></li><li data-sub-note-item="1-21"><div class="lab-step">Now, use colored pencils to draw the observed bacteria in the appropriate magnification circles and fill in the observed characteristics in the appropriate column, noting the bacteria&#39;s shape and whether it is Gram-positive, identified by darker purple staining, or Gram-negative, identified with pink staining. <a href="https://www.jove.com/CDNSource/lm/labs/28/Table_2_Microbial_diversity.xlsx" style="display:block;margin:20px;" target="__blank">Click Here to download Table 2</a>
</div></li><li data-sub-note-item="1-22"><div class="lab-step">Finally, repeat the observation, drawing, and characterization for the other two stained bacterial slides.
</div></li></ul></li><li data-note-item="2" data-parent-collapse="">Examining Fungal Structures
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="2-1"><div class="lab-step">Remove the <em>S. cerevisiae</em> plate from the incubator and place a drop of water onto a microscope slide.
</div></li><li data-sub-note-item="2-2"><div class="lab-step">Using a sterilized inoculating loop, smear a film of yeast into the drop of water and place a cover slip over the slide.
</div></li><li data-sub-note-item="2-3"><div class="lab-step">Place the slide under the microscope at the lowest magnification, increasing the magnification to the oil immersion setting to see the individual yeast cells.
</div></li><li data-sub-note-item="2-4"><div class="lab-step">Observe the general shape and structure of the yeast and identify any cells that are undergoing asexual reproduction by budding.
</div></li><li data-sub-note-item="2-5"><div class="lab-step">Now, draw the cells in the appropriate magnification circles.
</div></li><li data-sub-note-item="2-6"><div class="lab-step">When you are done observing the yeast, replace the <em>S. cerevisiae</em> slide with a prepared Ascomycetes apothecium slide and set the microscope to the lowest magnification.
</div></li><li data-sub-note-item="2-7"><div class="lab-step">Using colored pencils, draw the structures at low and high magnifications, including the asci and ascospores.
</div></li><li data-sub-note-item="2-8"><div class="lab-step">Finally, place a button mushroom, <em>Agaricus bisporus</em>, under the dissecting microscope and draw the features, including the pileus, or cap, the gills, and the stipe, or stalk.
</div></li></ul></li><li data-note-item="3" data-parent-collapse="">Results
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="3-1"><div class="lab-step">Using the coloring of the bacteria recorded in the table, determine which species are Gram-positive and which are Gram-negative.
</div></li><li data-sub-note-item="3-2"><div class="lab-step">Then, look at the shapes recorded in the table to determine which bacterial species are bacillus, coccus, or spirillum.
</div></li><li data-sub-note-item="3-3"><div class="lab-step">Next compare your illustrations of the yeast cells to your illustrations of the bacterial cells. NOTE: Yeast from the Ascomycetes phylum, such as <em>S. cerevisiae</em>, can reproduce asexually, which can be observed through the budding of the cells under a microscope.
</div></li><li data-sub-note-item="3-4"><div class="lab-step">Record any observations of yeast cells budding.  NOTE: Ascomycetes can also reproduce sexually via mitosis and haploid spore formation.
</div></li><li data-sub-note-item="3-5"><div class="lab-step">Record any observations of spore or asci formation you observed in the table.
</div></li><li data-sub-note-item="3-6"><div class="lab-step">NOTE: Fungus from the Basidiomycota phylum exhibit clearly observable gills under the pileus.
</div></li><li data-sub-note-item="3-7"><div class="lab-step">Record any fungal species that demonstrated gills under the pileus.
</div></li></ul></li></ol>

Microbial Colony and Fungal Diversity - Procedure

Diversità microbica e fungina

Examining Microbial Colony Structures
ExpandTo begin, collect your allocated culture plates and then remove the Parafilm and lid from one of them.
Place ...

Measuring Biodiversity

<ol class="note-items"><li data-note-item="1" data-parent-collapse="">Quadrats and Transects
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="1-1"><div class="lab-step">In this activity, you will be using quadrats along transect lines to take biodiversity measurements of the plant species in three distinct habitats near your classroom. Begin by splitting into groups. Four works best.
</div></li><li data-sub-note-item="1-2"><div class="lab-step">Select one person in your group to be the data recorder. The other three will be the data collectors.
</div></li><li data-sub-note-item="1-3"><div class="lab-step">Next, take one quadrat, or hula hoop, per group and place it on one side of one transect, or rope, next to a knot to allow identification of the plant species encircled by your quadrat. HYPOTHESES: For this experiment, the alternative hypothesis is that the alpha diversity will be smaller than gamma, meaning that there will be differences in the species that are present in each different habitat. The null hypothesis for this activity is that the alpha and gamma will be equal, meaning that there will be no species diversity difference between the communities sampled.
</div></li><li data-sub-note-item="1-4"><div class="lab-step">Each data collector must survey and identify the different plant species or any morphologically distinct varieties within your group&#39;s quadrat, giving the name of each plant type that you identify to the data recorder. It may seem like there are only a couple of species present at first, but look closer. It may take several minutes to find them all. 
</div></li><li data-sub-note-item="1-5"><div class="lab-step">In addition to recording the species name, the data recorder must also write a short description in the table, so that each species can be identified again in subsequent quadrats. <a href="https://www.jove.com/CDNSource/lm/labs/25/Table_1_Measuring_biodiversity.xlsx" style="display:block;margin:20px;" target="__blank">Click Here to download Table 1</a>
</div></li><li data-sub-note-item="1-6"><div class="lab-step">Once all of the species within a quadrat have been identified, pick up your hoop and move on to the next knot along the same transect.
</div></li><li data-sub-note-item="1-7"><div class="lab-step">Continue surveying and moving to the next knot until you have completed the entire rope transect.
</div></li><li data-sub-note-item="1-8"><div class="lab-step">Once you have completed the rope, move to a transect in a different habitat, and begin identifying the different species within each quadrat along the new transect, until each group has identified plants along three lengths of rope, one in each habitat, for a total of 15 quadrats surveyed.
</div></li><li data-sub-note-item="1-9"><div class="lab-step">When all of the species data have been collected, carry the transects and quadrats back to the classroom.
</div></li></ul></li><li data-note-item="2" data-parent-collapse="">Species-Accumulation Curves and Richness/Evenness 
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="2-1"><div class="lab-step">In the next activity, you will be calculating and comparing the species richness and evenness in two distinct populations, represented here by two opaque bags containing beads of various colors. For this exercise, start by taking one paper bag of beads per group.
</div></li><li data-sub-note-item="2-2"><div class="lab-step">Have one person reach into the bag and randomly pull out three beads without looking.
</div></li><li data-sub-note-item="2-3"><div class="lab-step">Write down the bead colors, as well as the total number of colors pulled from the bag in the table. <a href="https://www.jove.com/CDNSource/lm/labs/25/Table_2_Measuring_biodiversity.xlsx" style="display:block;margin:20px;" target="__blank">Click Here to download Table 2</a>HYPOTHESES: In this activity, the alternative hypothesis states that species evenness in the two communities will be different, while the richness will be the same. The null hypothesis might be that species richness and evenness will be the same in both communities.
</div></li><li data-sub-note-item="2-4"><div class="lab-step">Place the beads back in the bag after their colors are recorded.
</div></li><li data-sub-note-item="2-5"><div class="lab-step">Then, shake the bag and have the next person in the group draw another set of three beads.
</div></li><li data-sub-note-item="2-6"><div class="lab-step">Record the colors and numbers of beads that they pulled in the table.
</div></li><li data-sub-note-item="2-7"><div class="lab-step">Record the colors in the second row and the cumulative number of colors drawn in the last column.
</div></li><li data-sub-note-item="2-8"><div class="lab-step">Continue to take turns drawing three beads from the bag until 20 samples have been drawn.
</div></li><li data-sub-note-item="2-9"><div class="lab-step">Next, switch bags with a group with a bag from the other community, and repeat the exercise of drawing 20 samples, recording the color data in the appropriate community column of the table.
</div></li><li data-sub-note-item="2-10"><div class="lab-step">When all of the data have been recorded, return the beads to the bag and return the bags to your instructor.
</div></li></ul></li><li data-note-item="3" data-parent-collapse="">Results
<button class="expand">Expand</button><ul class="lab-items"><li data-sub-note-item="3-1"><div class="lab-step">To calculate the alpha diversity of the transect and quadrat data collected by your group, use the data your data recorder entered for each species and enter it into your diversity table. <a href="https://www.jove.com/CDNSource/lm/labs/25/Table_3_Measuring_biodiversity.xlsx" style="display:block;margin:20px;" target="__blank">Click Here to download Table 3</a>
</div></li><li data-sub-note-item="3-2"><div class="lab-step">Then, fill out the alpha diversity for each habitat into the appropriate column in the table.
</div></li><li data-sub-note-item="3-3"><div class="lab-step">Use the species data from your quadrat and transect table and enter the beta diversity data into the appropriate data cells within the diversity table. NOTE: The beta diversity is the number of species that are unique between two habitats. In this video, there are three species in common between the two sites, but a total of six unique species, giving a beta diversity of six between site A and B.
</div></li><li data-sub-note-item="3-4"><div class="lab-step">To calculate the gamma diversity for your activity, use the data from your quadrat and transect table and enter the gamma diversity data into the appropriate data cell. NOTE: The gamma diversity is the number of species in all of the habitats within a single study. It is not the sum of all of the alpha diversities, because species that are common between habitats should be counted only once.
</div></li><li data-sub-note-item="3-5"><div class="lab-step">To construct species accumulation curves for both of the bead sampling communities, use your bead color selection data to plot the species by sampling effort. That is the number of total colors by sample in the graph for each bead bag community.
</div></li><li data-sub-note-item="3-6"><div class="lab-step">Then, estimate the asymptote of the plotted data by appearance. Predict the number of species you would expect to find in each community. Note any differences in appearance between the two curves. If it was easier to estimate the number of species in one of the communities, make a hypothesis to explain this observation.
</div></li><li data-sub-note-item="3-7"><div class="lab-step">To construct rank abundance curves for both of the bead sampling communities, use the color bead data to fill in the table for both community A and community B, listing the colors that were identified during the sampling in the color column, and adding the total number of beads of each color that was sampled in the abundance column. <a href="https://www.jove.com/CDNSource/lm/labs/25/Table_4_Measuring_biodiversity.xlsx" style="display:block;margin:20px;" target="__blank">Click Here to download Table 4</a>
</div></li><li data-sub-note-item="3-8"><div class="lab-step">Now, assign a rank to each color in the rank column, designating the color of the highest abundance the highest rank, rank one, and the color with the lowest abundance the lowest rank, rank 10. If there are multiple colors with the same number, just assign them consecutive ranks.
</div></li><li data-sub-note-item="3-9"><div class="lab-step">Plot individual rank abundance curves for the number of individuals by species ranked for the most to least common in both community A and community B. Compare the steepness of the two rank curves. Compare the richness and evenness between the two communities. Identify the community that you consider more biodiverse. 
</div></li></ul></li></ol>

Misurare la biodiversità

Quadrats and Transects
ExpandIn this activity, you will be using quadrats along transect lines to take biodiversity measurements of the plant species in ...