Lecture Final exam Past review sheets

Question 1

what is biological species concept?

Answer 1

a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring

Question 2

distinguish between prezyogtic and posyzygotic reproductive barriers

Answer 2

prezygotic blocks fertilization and postzygotic prevents development of zygote

Question 3

5 prezygotic reproductive barriers and examples

Answer 3

1) habitat isolation (garter snakes, one on land and one on water)
2) temporal isolation (spotted skunk)
3) behavioral isolation (blue footed boobies)
4) mechanical isolation (shells of 2 snails)
5) gametic isolation (sea urchins)

Question 4

explain how hyrbrid breakdown maintains separate species even if gene flow occurs

Answer 4

offspring of hybrids may be weak/sterile. may be present but cannot become genetically independent.

Question 5

describe some limitations of the biological species concept

Answer 5

extinct forms cannot be tested. Asexual forms are isolated, period.

Question 6

what is allopatric speciation?

Answer 6

physical separation results in speciation due to reproductive isolation

Question 7

what is sympatric speciation?

Answer 7

divergence in place due to instrinsic factors such as sexual selection, habitat differentiation and polyploidy