Exam 4 part 1

Question 1

gene frequency

Answer 1

allele frequency in a population

Question 2

Hardy Weinberg assumptions

Answer 2

• infinitely large
• random mating
• no selection
• no migration
• no mutation

Question 3

directional selection

Answer 3

favors one extreme or the other
- homozygotes favored

Question 4

disruptive selection

Answer 4

favors both extremes

Question 5

stabilizing selection

Answer 5

heterozygotes favored

Question 6

genetic drift

Answer 6

random loss and fixation of alleles

Question 7

founder effect

Answer 7

loss of genetic variation when a small population is created from a group leaving a larger population

Question 8

bottlenecking

Answer 8

a drastic size reduction due to some environmental event causing a loss of diversity

Question 9

assortative mating

Answer 9

mate based on phenotype

Question 10

positive assortative mating

Answer 10

mating like individuals together
- more homozygotes

Question 11

negative assortative mating

Answer 11

opposites attract
- more heterozygotes

Question 12

inbreeding

Answer 12

changes frequency of genotypes but not allele frequency
- more homozygotes

Question 13

non random mating changes …

Answer 13

frequency of genotypes but not allele frequency

Question 14

evolution 2 step process

Answer 14

1. genetic variation arises
2. alleles increase or decrease in frequency in the gene pool

Question 15

reproductive isolation

Answer 15

species can no longer exchange genes

Question 16

prezygotic reproductive isolation

Answer 16

ecological, behavioral, temporal, mechanical, and gametic

Question 17

ecological isolation

Answer 17

differences in habitat

Question 18

behavioral isoaltion

Answer 18

differences in mating behavior

Question 19

temporal isolation

Answer 19

reproduction takes place at different times

Question 20

mechanical isolation

Answer 20

anatomical differences

Question 21

gametic isolation

Answer 21

gametes are incompatible

Question 22

postzygotic reproductive isolation

Answer 22

hybrid inviability, hybrid sterility, hybrid breakdown

Question 23

hybrid inviability

Answer 23

hybrid zygote does not survive to reproduction

Question 24

hybrid sterility

Answer 24

hybrid is sterile

Question 25

hybrid breakdown

Answer 25

F2 is inviable or sterile

Question 26

allopatric speciation

Answer 26

geographic barrier initiates speciation by blocking gene flow

Question 27

allopatric speciation example

Answer 27

darwins finches (beak size)

Question 28

sympatric speciation

Answer 28

a single interbreeding population without a geographic barrier

Question 29

sympatric speciation example

Answer 29

apple maggot fly change in diet