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href="gene-pools-and-speciation-103-hl.html">Gene pools and speciation 10.3 HL</a></label></li></ul></div> <div class="hidden-xs hidden-sm"> <button class="btn btn-default btn-block text-xs-center" data-toggle="modal" data-target="#modal-feedback" style="margin-bottom: 10px"><i class="fa fa-send"></i> Feedback</button> </div> </div> <div class="col-md-9" id="main-column"> <h1 class="page_title"> Gene pools and speciation 10.3 HL <a href="#" class="mark-page-favorite pull-right" data-pid="1343" title="Mark as favorite" onclick="return false;"><i class="fa fa-star-o"></i></a> </h1> <ol class="breadcrumb"> <li><a href="../../../biology.html"><i class="fa fa-home"></i></a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><a href="../472/10-genetics-ahl.html">10 Genetics AHL</a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><span class="gray">Gene pools and speciation 10.3 HL</span></li> <span class="pull-right" style="color: #555" title="Suggested study time: 30 minutes"><i class="fa fa-clock-o"></i> 30'</span> </ol> <article id="main-article"> <style type="text/css">ol.breadcrumb { margin-bottom: 0 }</style><div id="toc-1675505974" class="toc"><a href="#" class="toc-switcher" title="Show table of contents"><small><i class="fa fa-reorder"></i> Table of contents <span class="pull-right"><i class="fa fa-chevron-down"></i></span></small></a><ol><li><a href="#header-1" class="scroll-to" data-target="header-1">Summary list for 10.3 Gene pools and speciation</a></li><li><a href="#header-2" class="scroll-to" data-target="header-2">Mindmaps</a></li><li><a href="#header-3" class="scroll-to" data-target="header-3">Exam style question about speciation</a></li><li><a href="#header-4" class="scroll-to" data-target="header-4">Model answer</a></li><li><a href="#header-5" class="scroll-to" data-target="header-5">Model answer</a></li><li><a href="#header-6" class="scroll-to" data-target="header-6">Model answer</a></li><li><a href="#header-7" class="scroll-to" data-target="header-7">Multiple choice questions</a><ol></ol></li><li><a href="#header-8" class="scroll-to" data-target="header-8"> 10.3 Gene pools and speciation 1/1 </a></li></ol><li><a href="#header-9" class="scroll-to" data-target="header-9">Drag and drop activities</a></li><li><a href="#header-10" class="scroll-to" data-target="header-10">Just for fun</a></li></div><ul> </ul> <div class="intro-card" readonly="false"><img class="intro-image" readonly="true" src="../../images/10_geneticshl/polyploid_strawberry.jpg" style="width: 200px; height: 149px;"> <div class="content" readonly="true"> <div class="text">The concept of gene pools is important to the understanding of natural selection. There are three types of selection pressure covered in this topic, stabilising, directional and disruptive. In situations where there is reproductive isolation between two populations of a species speciation can occur. This topic explores this mechanism of evolution and the concepts of punctuated equilibrium and polyploidy</div> </div> </div> <div class="panel panel-turquoise"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Key concepts</p> </div> </div> <div class="panel-body"> <div> <p>Learn and test your biological vocabulary using these <strong>10.3 Gene pools and speciation</strong> flashcards.</p> <p style="text-align: center"><iframe height="500" src="https://quizlet.com/518247350/flashcards/embed?i=xxmo&x=1jj1" style="border:0" width="100%"></iframe></p> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-default"> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-yellow"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Essentials</p> </div> </div> <div class="panel-body"> <div> <p>These slides summarise the essential understanding and skills in this topic. <br> They contain short explanations in text and images - great revision.</p> <p>Read the slides and look up any words or details you find difficult to understand.</p> <div id="carousel-205" class="dynamic-gallery carousel slide" data-id="205"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/5-205/103genepools-1.jpg" data-fancybox="gallery-205" title="" data-caption=""><img alt="" src="../../../std-galleries/5-205/103genepools-1.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-205/103genepools-2.jpg" data-fancybox="gallery-205" title="" data-caption=""><img alt="" src="../../../std-galleries/5-205/103genepools-2.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-205/103genepools-3.jpg" data-fancybox="gallery-205" title="" data-caption=""><img alt="" src="../../../std-galleries/5-205/103genepools-3.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-205/103genepools123-4.jpg" data-fancybox="gallery-205" title="" data-caption=""><img alt="" src="../../../std-galleries/5-205/103genepools123-4.jpg"></a></div></div><a class="left carousel-control" href="#carousel-205" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-205" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/5-205/103genepools-1-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/5-205/103genepools-2-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/5-205/103genepools-3-thumb128.jpg"><li><li data-index="3"><img title="Click to view" src="../../../std-galleries/5-205/103genepools123-4-thumb128.jpg"><li></li></ol> </div> </div> <div class="panel-footer"> <div> <p>These slides summarise the essential understanding and skills in this topic. <br> They contain short explanations in text and images - great revision.</p> <p>Read the slides and look up any words or details you find difficult to understand.</p> <div id="carousel-210" class="dynamic-gallery carousel slide" data-id="210"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/5-210/112movement-1.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-1.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-2.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-2.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-3.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-3.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-4.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-4.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-210/112movement-5.jpg" data-fancybox="gallery-210" title="" data-caption=""><img alt="" src="../../../std-galleries/5-210/112movement-5.jpg"></a></div></div><a class="left carousel-control" href="#carousel-210" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-210" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/5-210/112movement-1-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/5-210/112movement-2-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/5-210/112movement-3-thumb128.jpg"><li><li data-index="3"><img title="Click to view" src="../../../std-galleries/5-210/112movement-4-thumb128.jpg"><li><li data-index="4"><img title="Click to view" src="../../../std-galleries/5-210/112movement-5-thumb128.jpg"><li></li></ol> </div> </div> </div> <div class="panel panel-violet"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Summary</p> </div> </div> <div class="panel-body"> <div> <h3 id="header-1">Summary list for 10.3 Gene pools and speciation<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <p style="margin-left:2.0pt;"><u>Gene pools</u></p> <ul> <li class="liWithoutP">A gene pool consists of all the genes and their different alleles, present in an interbreeding population.</li> <li class="liWithoutP">Evolution requires that allele frequencies change with time in populations.</li> <li class="liWithoutP">Punctuated equilibrium implies long periods without appreciable change and short periods of rapid evolution.</li> </ul> <p><u>Speciation</u></p> <ul> <li class="liWithoutP">Reproductive isolation of populations can be temporal, behavioural or geographic.</li> <li class="liWithoutP">Speciation due to divergence of isolated populations can be gradual.</li> <li class="liWithoutP">Speciation can occur abruptly.</li> </ul> <div class="yellowBg"> <p><strong>Student skills and applications </strong></p> <ul> <li class="liWithoutP">Application: Identifying examples of directional, stabilising and disruptive selection.</li> <li class="liWithoutP">Application: Speciation in the genus <em>Allium</em> by polyploidy.</li> <li class="liWithoutP">Skill: Comparison of allele frequencies of geographically isolated populations.</li> </ul> </div> <hr class="hidden-separator"> <h3 id="header-2">Mindmaps<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <p>This diagram summaries the main sections of topic 10.3 about gene pools and speciation.<br> Test if you can draw something like these concept maps from memory.</p> <div id="carousel-204" class="dynamic-gallery carousel slide" data-id="204"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/5-204/103spiderfullgenepools.jpg" data-fancybox="gallery-204" title="" data-caption=""><img alt="" src="../../../std-galleries/5-204/103spiderfullgenepools.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-204/103spiderlistgenepools.jpg" data-fancybox="gallery-204" title="" data-caption=""><img alt="" src="../../../std-galleries/5-204/103spiderlistgenepools.jpg"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/5-204/103spidersimplegenepools.jpg" data-fancybox="gallery-204" title="" data-caption=""><img alt="" src="../../../std-galleries/5-204/103spidersimplegenepools.jpg"></a></div></div><a class="left carousel-control" href="#carousel-204" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-204" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/5-204/103spiderfullgenepools-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/5-204/103spiderlistgenepools-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/5-204/103spidersimplegenepools-thumb128.jpg"><li></li></ol> </div> </div> <div class="panel-footer"> <div> <p>text</p> </div> </div> </div> <div class="panel panel-default"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Exam style questions</p> </div> </div> <div class="panel-body"> <div> <h3 id="header-3">Exam style question about speciation<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <p>Answer the question below on a piece of paper, then check your answer against the model answer below.</p> <div class="yellowBg"> <p><strong>Describe how geographical isolation and different selective pressures can lead to speciation [3]</strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> <p><strong>....................................................................................... ............................................................................ </strong></p> <p><strong>.</strong></p> <p><strong>.</strong></p> </div> <p>Click the + icon to see a model answer.</p> <button class="btn btn-xs bg-turquoise showhider"><i class="fa fa-fw fa-plus"></i></button><section class="hiddenbox hidden"> <div class="yellowBg"> <h3 id="header-4">Model answer<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <p>Any three of these.</p> <ul> <li><span style="color:#FF0000;">Geographical isolation cause to populations of a species to stop interbreeding.</span></li> <li><span style="color:#FF0000;">If each population has a different selection pressure they will evolve in different ways.</span></li> <li><span style="color:#FF0000;">As selection pressures will favour different genes or alleles.</span></li> <li><span style="color:#FF0000;">If these differences become great enough they prevent interbreeding even if the populations are reunited.</span></li> <li><span style="color:#FF0000;">The two populations will have become separate species, this is speciation.</span></li> </ul> </div> </section> <div class="panel panel-has-colored-body panel-expandable panel-has-border panel-default"> <div class="panel-heading"> <div> <p>Extra exam question on polyploidy and abrupt speciation. Click to open.</p> </div> </div> <div class="panel-body"> <div> <p>Linking genetic chnages to evolution is an important concept in this topic.</p> <p>Answer the question below on a piece of paper, then check your answer against the model answer below.</p> <p><span style="font-family:arial,helvetica,sans-serif;"><b><span lang="EN-GB" style="font-size: 11pt; line-height: 106%;">Explain how polyploidy can cause abrupt speciation. (3 marks)</span></b><strong>.</strong></span></p> <div class="yellowBg"> <hr> <hr> <hr> <hr><em>Hint: Make sure that your answer links polyploidy to speciation.</em></div> Click on the "+" icon to see a model answer. <button class="btn btn-xs bg-turquoise showhider"><i class="fa fa-fw fa-plus"></i></button><section class="hiddenbox hidden"> <h3 id="header-5">Model answer<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <div class="yellowBg"> <p><span style="font-family:arial,helvetica,sans-serif;"><b><span lang="EN-GB" style="font-size: 11pt; line-height: 106%;">Explain how polyploidy can cause abrupt speciation. (3 marks<strong>)</strong></span></b><strong>.</strong></span></p> <p><em>Speciation can be gradual (occur over long time periods) or abrupt (occur over one or a few generations).</em></p> <p><em>Explain – give reasons. Begin with defining the term in the question.</em></p> <ul> <li><span style="color:#FF0000;">Polyploid organisms have three or more complete sets of chromosomes (a diploid organism has two sets of chromosomes).</span></li> <li><span style="color:#FF0000;">The gametes of the polyploid will not have the haploid number of chromosomes of the original (parent) species.</span></li> <li><span style="color:#FF0000;">This could mean that the polyploid organism is reproductively isolated from the parent population. (they can no longer interbreed).</span></li> <li><span style="color:#FF0000;">If the polyploid organism cannot interbreed with the parent species, it will become separate species.</span></li> <li><span style="color:#FF0000;">This isolation occurs in a single generation/occurs immediately when the polyploid is formed.</span></li> <li><span style="color:#FF0000;">The polyploid species has evolved in one generation so it is abrupt speciation.</span></li> </ul> </div> </section> <div class="panel panel-has-colored-body panel-expandable panel-has-border panel-default"> <div class="panel-heading"> <div> <p>Extra exam question on the gradual change of allele frequencies as a species evolves. Click to open.</p> </div> </div> <div class="panel-body"> <div> <div class="yellowBg"> <p>The understanding that evolution is a change in allele frequencies in gene pools over time is an important concept in this topic.</p> <p>Answer the question on a piece of paper, then check your answer against the model answer below.</p> <p><strong>Explain how environmental change can lead to changes in allele frequency in a single population. (4 marks).</strong></p> <hr> <hr> <hr> <hr><em>Hint: </em> <p><em>Explain requires the reasons for change in this question. The question is not about speciation but the evolution of a single species. It is necessary to link the two concepts in the question - environmental change and allele frequency changes.</em></p> </div> Click on the "+" icon to see a model answer. <button class="btn btn-xs bg-turquoise showhider"><i class="fa fa-fw fa-plus"></i></button><section class="hiddenbox hidden"> <h3 id="header-6">Model answer<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <div class="yellowBg"> <p><strong>Explain how environmental change can lead to changes in allele frequency in a single population. (4 marks).</strong></p> <ul> <li><span style="color:#FF0000;">Allele frequency is a measure of the proportion of a particular allele in a population.</span></li> <li><span style="color:#FF0000;">Changes in environement would alter selection pressures for particular alleles (would favour different alleles).</span></li> <li><span style="color:#FF0000;">Organisms with favoured alleles would breed successfully (those with less advantageous characteristics would be less successful in breeding and survival).</span></li> <li><span style="color:#FF0000;">This would lead to an increase in those alleles that confer survival.</span></li> <li><span style="color:#FF0000;">Alleles that have survival value (in the changed environmental conditions) would increase in the population, altering the allele frequencies.</span></li> <li><span style="color:#FF0000;">Changes in allele frequencies over time would result in the gradual evolution of a species.</span></li> </ul> </div> </section> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> </div> </div> </div> <div class="panel panel-green"> <div class="panel-heading"> <div> <p>Test yourself</p> </div> </div> <div class="panel-body"> <div> <h3 id="header-7">Multiple choice questions<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <p>This is a self marking quiz containing questions covering the topic outlined above.<br> Try the questions to check your understanding.</p> <br><a class="btn btn-primary btn-block text-center" data-toggle="modal" href="#efacd935"><i class="fa fa-play"></i> START QUIZ!</a><div class="modal fade modal-slide-quiz" id="efacd935"> <div class="modal-dialog" style="width: 95vw; max-width: 960px"> <div class="modal-content"> <div class="modal-header slide-quiz-title"> <h4 id="header-8"> 10.3 Gene pools and speciation <strong class="q-number pull-right"> <span class="counter">1</span>/<span class="total">1</span> </strong> <small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h4> </div> <div class="modal-body p-xs-3"> <div class="slide-quiz" data-stats="5-532-1343" style="opacity: 0"> <div class="exercise shadow-bottom"><div class="q-question"><p>Which of the following is the best definition of a gene pool? </p></div><div class="q-answer"><p><label class="radio"><input type="radio"> All the chromosomes in the cells of an individual organism.</label></p><p><label class="radio"><input type="radio"> All the alleles of a single gene which exist in a population.</label></p><p><label class="radio"><input class="c" type="radio"> All the genes and all their different alleles in an interbreeding population.</label></p><p><label class="radio"><input type="radio"> All the genes an alleles available in the genomes of two organisms when they mate.</label></p></div><div class="q-explanation"><p>A gene pool consists of all the genes and their different alleles, present in an interbreeding population.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>Imagine that the colourings of these beetles was caused by two genes, each gene with just two alleles. We can see that there is a slight variation in the phenotype, caused by these genes, because each beetle has a unique assortment of alleles.</p><p><img alt="" src="../../images/10_geneticshl/gene-pool-variation-beetles.jpg" style="width: 400px; height: 71px;"></p><p>Suggest what would happen to the frequency of the allele causing the shiny red spot,over several years, if this made beetles more visible to a predator.</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> The allele frequency of the red spot allele would increase over time, by evolution.</label></p><p><label class="radio"><input type="radio"> The allele frequency of the red spot allele would stay the same over time, </label></p><p><label class="radio"><input type="radio"> The allele frequency of the red spot allele would change randomly, the same as all the other alleles.</label></p><p><label class="radio"><input class="c" type="radio"> The allele frequency of the red spot allele would reduce over time.</label></p></div><div class="q-explanation"><p>Evolution requires that allele frequencies change with time in populations.<br>In this example, if a predator eats more of the beetles with a red spot, then the frequency of the red spot allele in the gene pool will reduce.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>Which of the statements is the best definition of "an allele frequency"?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> The number of times the allele is seen in the genome of an organism in the population.</label></p><p><label class="radio"><input class="c" type="radio"> The total number copies of the allele in the interbreeding population.</label></p><p><label class="radio"><input type="radio"> The number of time the allele is seen a population.</label></p><p><label class="radio"><input type="radio"> The number of genotypes containing the allele in the population.</label></p></div><div class="q-explanation"><p>The allele frequency is simply the number of alleles found in the whole interbreeding population. <br>Homozygous individuals will have two copies of the allele.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>Speciation requires two populations to be "reproductively isolated" from each other.</p><p>Which of the following lists three methods of reproductive isolation?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Sexual, geographic, aquatic</label></p><p><label class="radio"><input type="radio"> Mutagenic, geographic, genetic.</label></p><p><label class="radio"><input type="radio"> Behavioural, genetic, reproductive</label></p><p><label class="radio"><input class="c" type="radio"> Temporal, behavioural or geographic.</label></p></div><div class="q-explanation"><p>Reproductive isolation of populations can be temporal (they are active at different times), behavioural (courtship of some males does not attract some females, or geographic the animals cannot cross a river, or a mountain.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>If two populations of a species are geographically isolated what type of evolution could lead to the situation where two groups of organisms of this species can no longer interbreed if they met?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Mutagenic evolution.</label></p><p><label class="radio"><input class="c" type="radio"> Divergent evolution.</label></p><p><label class="radio"><input type="radio"> Directional evolution.</label></p><p><label class="radio"><input type="radio"> Convergent evolution.</label></p></div><div class="q-explanation"><p>Divergent evolution can lead to speciation.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>In the genus <em>Allium,</em> new species have been know to form very rapidly by a special type of speciation.<br>It is a condition where gametes containing more than one set of chromosomes produce offspring.</p><p>What is this condition called?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> A-sexual reproduction.</label></p><p><label class="radio"><input type="radio"> Punctuated equilibrium</label></p><p><label class="radio"><input class="c" type="radio"> Polyploidy</label></p><p><label class="radio"><input type="radio"> Polyspermy</label></p></div><div class="q-explanation"><p>Speciation can occur in the genus Allium by polyploidy. Diploid, tetraploid, and other types are common.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>The images shows two varieties of strawberries.</p><p><img alt="" src="../../images/10_geneticshl/polyploid_strawberry.jpg" style="width: 300px; height: 223px;"></p><p>One of these fruits came from a polyploid variety.</p><p>Which is the best description of the potential advantages of polyploidy?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> They are genetically modified and therefore resist disease.</label></p><p><label class="radio"><input type="radio"> They are often smaller and have a stronger taste.</label></p><p><label class="radio"><input class="c" type="radio"> They are often bigger and produce a greater yield.</label></p><p><label class="radio"><input type="radio"> They have more DNA so are seedless.</label></p></div><div class="q-explanation">There are some variety of fruit, like bananas and water melon which can be seedless. These are polyploid varieties, usually triploid.<br>In the case of these strawberries they are covered in seeds so they are not seedless.<br>Polyploid varieties can occur naturally but often they are induced by crop breeders because they produce a greater yield.</div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>What is the term which describes long periods of time with no significant change followed by a shorter period of quite fast evolution?</p></div><div class="q-answer"><p><label class="radio"><input type="radio"> Punctuated evolution.</label></p><p><label class="radio"><input type="radio"> Gradual evolution.</label></p><p><label class="radio"><input class="c" type="radio"> Punctuated equilibrium.</label></p><p><label class="radio"><input type="radio"> Directional equilibrium.</label></p></div><div class="q-explanation"><p>Punctuated equilibrium implies long periods without appreciable change and short periods of rapid evolution.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="exercise shadow-bottom"><div class="q-question"><p>What is the difference between allele frequency ?</p></div><div class="q-answer"><p><label class="radio"><input class="c" type="radio"> A gene pool is all the genetic material in an interbreeding population and a genome is all the genetic material in an organism.</label></p><p><label class="radio"><input type="radio"> Wrong answer</label></p><p><label class="radio"><input type="radio"> Wrong answer</label></p><p><label class="radio"><input type="radio"> Wrong answer</label></p></div><div class="q-explanation"><p>A gene pool consists of all the genes and their different alleles, present in an interbreeding population.</p></div><div class="slide-q-actions"><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div> </div> </div> <div class="modal-footer slide-quiz-actions"> <div class=""> <div class="pull-left pull-xs-none mb-xs-3"> <button class="btn btn-default d-xs-none btn-prev"> <i class="fa fa-arrow-left"></i> Prev </button> </div> <div class="pull-right pull-xs-none"> <button class="btn btn-success btn-xs-block text-xs-center btn-results" style="display: none"> <i class="fa fa-bar-chart"></i> Check Results </button> <button class="btn btn-default d-xs-none btn-next"> Next <i class="fa fa-arrow-right"></i> </button> <button class="btn btn-default btn-xs-block text-xs-center btn-close" data-dismiss="modal" style="display: none"> Close </button> </div> </div> </div> </div> </div></div> <h3 id="header-9">Drag and drop activities<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <p>Test your ability to construct biological explanations using the drag and drop questions below.</p> <div class="tib-quiz" data-stats="5-905-1343"><p>Isolation of two populations is a mechanism of speciation.</p><p>Drag and drop the correct word or phrase into the gap to outline isolation mechanisms.</p><div class="label label-default q-number">1</div><div class="exercise shadow-bottom"><div class="q-question"><p class="gap-drop"> <span class="q-text-draggable draggable" draggable="true">Behavioural</span> <span class="q-text-draggable draggable" draggable="true">Natural</span> <span class="q-text-draggable draggable" draggable="true">mechanisms</span> <span class="q-text-draggable draggable" draggable="true">seasons</span> <span class="q-text-draggable draggable" draggable="true">Temporal</span> <span class="q-text-draggable draggable" draggable="true">interbreeding</span> <span class="q-text-draggable draggable" draggable="true">physical barrier</span> <span class="q-text-draggable draggable" draggable="true">Breeding</span> <span class="q-text-draggable draggable" draggable="true">selection pressures</span> <span class="q-text-draggable draggable" draggable="true">characteristics</span></p></div><div class="q-answer"><p>Isolation prevents two groups of a species from <input type="text" style="height: auto;" data-c="interbreeding"> <span class="review"></span> . If each of the groups is subjected to differing <input type="text" style="height: auto;" data-c="selection pressures"> <span class="review"></span> , their genomes will gradually evolve in different ways due to different genes having favourable <input type="text" style="height: auto;" data-c="characteristics"> <span class="review"></span> in the different environments.</p><p>Three forms of isolating <input type="text" style="height: auto;" data-c="mechanisms"> <span class="review"></span> are:</p><ol><li>Geographical isolation where a <input type="text" style="height: auto;" data-c="physical barrier"> <span class="review"></span> such as a river separates the two populations.</li><li> <input type="text" style="height: auto;" data-c="Temporal"> <span class="review"></span> isolation where the activity times or breeding <input type="text" style="height: auto;" data-c="seasons"> <span class="review"></span> separate the two populations.</li><li> <input type="text" style="height: auto;" data-c="Behavioural"> <span class="review"></span> isolation where members of each group choose to breed only with members of that group</li></ol></div><div class="q-explanation"><p><em>Isolation prevents interbreeding and can lead to speciation over time.</em></p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="totals"><span class="score"></span><button class="btn btn-success btn-block text-center check-total"><i class="fa fa-check-square-o"></i> Check</button></div></div><hr> </div> </div> </div> <div class="panel panel-fucsia"> <div class="panel-heading"><a class="expander pull-right" href="#"><span class="fa fa-plus"></span></a> <div> <p>Just for fun</p> </div> </div> <div class="panel-body"> <div> <h3 id="header-10">Just for fun<small class="toc-back-button"><a href="#" class="scroll-to" data-target="toc-1675505974" title="Back to table of contents"><i class="fa fa-chevron-circle-up gray"></i></a></small></h3> <p>Everyone needs a bit of fun while they revise. 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