Sheet 14 Flashcards
Why do we expect the frequency of the CCR5 32 allele will increase in humans?
because it causes aids resistence.
how have the selective agents that affect humans changed recently?
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what are the 4 main lines of evidence that indicate that macroevoultion has occured?
1) fossil record
2) comparitive anatomy
3) molecular record
what is the fossil record and how is it used?
Date of the rocks reflects age of the fossil by use of radioactive decay.
–provide evidence of progressive evolutionary change
why is comparitive anatomy useful for studying evoultion?
because organisms with similar structurs must have acquired the traits from a common ancestor.
what is a vestigal structure, and what are some vestigual structures in humans?
a structure in an organism that has lost its orginal function through the course of evolution.
ex. appendix, sinuses,eee
what does ‘embryology recapitulates phylogeny mean?
false hypotheiss that states when animals go though embryological development they go through all the evoultionary stages
what is a species
largest groups of organisms capable of interbreeding and producing fertile offspring.
what is the basic idea used to define a species, and why is this a problem?
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what is an ecotype?
a locally adapted variant of an organism, genetically different from others of same species
what is a niche. and what is a habitat?
a small category that animals will excell because of
habitat– ecological or enviromental area that is inhabited by a particular species of aimals, plant
what are the usualy steps to speciation?
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what is alloatric speciation?
speciation that occurs when biological populations of same species become isolated from each other by geography.–in time the species evolves to fit the enviroment
how can sympatric speciation occur?
one population of one species became two species while in the same geographic region with no physical separation–usually occurs because different individuals of the same species begin to occupy a distinct niche.
why can polyploidy result in the formation of a new species?
organisms containing more than two paried sesets of chromosomes.–causes instantaneous speciation
what are the two classes of barriers to hybridization?
1) prezygotic–prevent mating or fertilization between different species
2) postzygotic–reproductive barrier that operates should interspecies mating occur and form hybrid zygotes–prevents development of zygotes
what are ecological isolation, temporal isolation, behavorial isolation, and mechanical isolation?
Ecological isolation–
Temporal isolation– prezygotic–different species reproduce at different times
behavioral isolation– prezygotic– species have differences in mating rituals
mechanical isolation– prezygotic–species are physcially unable to reproduce
what are the two most important postzygotic isolating mechanisms?
1) hybrids develop imporperly
2) Experimental manipulatino of plant hybrids
*hybrids weaker than parents and eliminates in nature
why are hybrids important for evolution of a new species?
because some hybrids are better suited to an enviroment than the parents and the have greater opportunity to recombine alleles.
why do new species arise?
.
what is adaptive radiation?
existence of closely related species within a genera, evolved recently from common ancestor, usually caused by enviromental factors
what is a species cluster, and what are some examples of species clusters?
species clusters usually occur because of adaptive radiation generates many new species.
ex. occurs on islands like the finches
how do you measure p2, 2pq, q2 by PCR?
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what are RLPS and STRs and what are they used for
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why did the number of brightest guppies cary when you changed the number of predators?
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why did p and q change more rapidly when you selected against the dominant?
;
after doing PCR on students from labs, we obtained 20 homozygous large bands, 76 heterozygtes and 4 homozygous small bands, what is frequency of small allele?
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