Sheet 14

Question 1

Why do we expect the frequency of the CCR5 32 allele will increase in humans?

Answer 1

because it causes aids resistence.

Question 2

how have the selective agents that affect humans changed recently?

Answer 2

.

Question 3

what are the 4 main lines of evidence that indicate that macroevoultion has occured?

Answer 3

1) fossil record
2) comparitive anatomy
3) molecular record

Question 4

what is the fossil record and how is it used?

Answer 4

Date of the rocks reflects age of the fossil by use of radioactive decay.
–provide evidence of progressive evolutionary change

Question 5

why is comparitive anatomy useful for studying evoultion?

Answer 5

because organisms with similar structurs must have acquired the traits from a common ancestor.

Question 6

what is a vestigal structure, and what are some vestigual structures in humans?

Answer 6

a structure in an organism that has lost its orginal function through the course of evolution.

ex. appendix, sinuses,eee

Question 7

what does ‘embryology recapitulates phylogeny mean?

Answer 7

false hypotheiss that states when animals go though embryological development they go through all the evoultionary stages

Question 8

what is a species

Answer 8

largest groups of organisms capable of interbreeding and producing fertile offspring.

Question 9

what is the basic idea used to define a species, and why is this a problem?

Answer 9

.

Question 10

what is an ecotype?

Answer 10

a locally adapted variant of an organism, genetically different from others of same species

Question 11

what is a niche. and what is a habitat?

Answer 11

a small category that animals will excell because of

habitat– ecological or enviromental area that is inhabited by a particular species of aimals, plant

Question 12

what are the usualy steps to speciation?

Answer 12

.

Question 13

what is alloatric speciation?

Answer 13

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

Question 14

how can sympatric speciation occur?

Answer 14

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.

Question 15

why can polyploidy result in the formation of a new species?

Answer 15

organisms containing more than two paried sesets of chromosomes.–causes instantaneous speciation

Question 16

what are the two classes of barriers to hybridization?

Answer 16

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

Question 17

what are ecological isolation, temporal isolation, behavorial isolation, and mechanical isolation?

Answer 17

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

Question 18

what are the two most important postzygotic isolating mechanisms?

Answer 18

1) hybrids develop imporperly
2) Experimental manipulatino of plant hybrids

*hybrids weaker than parents and eliminates in nature

Question 19

why are hybrids important for evolution of a new species?

Answer 19

because some hybrids are better suited to an enviroment than the parents and the have greater opportunity to recombine alleles.

Question 20

why do new species arise?

Answer 20

.

Question 21

what is adaptive radiation?

Answer 21

existence of closely related species within a genera, evolved recently from common ancestor, usually caused by enviromental factors

Question 22

what is a species cluster, and what are some examples of species clusters?

Answer 22

species clusters usually occur because of adaptive radiation generates many new species.

ex. occurs on islands like the finches

Question 23

how do you measure p2, 2pq, q2 by PCR?

Answer 23

.

Question 24

what are RLPS and STRs and what are they used for

Answer 24

.

Question 25

why did the number of brightest guppies cary when you changed the number of predators?

Answer 25

.

Question 26

why did p and q change more rapidly when you selected against the dominant?

Answer 26

;

Question 27

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?

Answer 27

.