Lab 8 | Evidence for Incipient Speciation

Lab 8 | Evidence for Incipient Speciation | Pre-lab Date of Lab: May 19th, 2016

1.            Inyourownwords,explain whygeneflowamongpopulationsreducesthepotentialforlocal adaptation within eachpopulation.

2.            Inyourownwords,explainwhatismeantby“prezygoticmechanismsofreproductive isolation”.

3.            Reviewtheexperimentsdescribedforhawfliesandapplefliesandlisttwokindsofprezygotic isolationmentioned.

b.            Theymayalsonevermeetiftheychooseanexacttimetoemergefromtheground(the apple flies come out first and leave, then the haw flies comeout)

4.            Inyourownwords,explainwhatismeantby“postzygoticmechanismsofreproductive isolation”.

5.            Reviewtheexperimentsdescribesforhawfliesandapplefliesandnameonekindofpostzygotic isolation that isoperating.

6.            Howmanygenerationsofsoapberrybugscantherebeeachyear? a.10-12

7.            Why might you expect to see a difference in beak length between males andfemales?

8.            Giventheradiusofaballoonvineseedcapsuleandfitnessofbugswithdifferentbeaklengths undernaturalselection,whatbeaklengthwouldbeidealforfeedingonballoonvinefruits?

9.            In a natural population of bugs living on balloon vine in Baton Rouge, Louisiana, female beak lengthrangedfrom6.5to9.5mmwithameanat8mm.Howwelldoesthisdistributionfityour expectation?

10.          What fraction of available balloon vine fruits could this population of bugsconsume?

11.          Wouldhavingabeaklongerthanthelargestradiusbemoreeffectivethanhavingabeakequal to the average capsuleradius?

12.          Thereisnaturalvariationinbeaklengthwithinabugpopulation.Listtwoothertraitswouldyou expect to vary with beak length in a bugpopulation?

13.          Accordingtoscenario,arelarge,smalloraveragebugsmorelikelytohavehigherfitnessonthe new foodsource?

14.          Changethatwewouldreasonablyexpectinbugpopulationsthathavebeenlivingongoldenrain trees.

15.          Dispersing bug or one with less developed flight muscles more likely to have higherfitness?

16.          If bugs disperse, what are the costs and benefits of accepting host plants of eitherspecies?

17.          How could a dispersing bug know what species of plants it would be settlingon?

18.          Verybrieflyoutlineanexperimenttodemonstratethatadispersingbugwasabletodiscriminate one species of plant fromanother.

19.          Whatwouldconstitutea“suitable”matefor aparticularbug,assumingthatreproductionwitha suitable mate produces high fitnessoffspring?

20.          Tofindasuitablemate,doesabughavetocomparethebodyofthepotentialmatetoitsown body, or are there other cues that could beused?

21.          Howdoesthenumberofgenerationsperyearinfluencethelikelihoodofseeingaresponseto natural selection once a new host plant has beencolonized?