chapter twenty-four part two

Question 1

2 ways of speciation

Answer 1

allopatric and sympatric

Question 2

allopatric speciation

Answer 2

• gene flow reduced when population divided into geographically isolated subpopulations

Question 3

for allopatric speciation, the definition of a barrier depends on

Answer 3

the ability of a population to disperse

Question 4

in allopatric speciation, separate populations and reproductive isolation may arise from what?

Answer 4

natural selection, mutation, genetic drift, sexual selection

Question 5

are there more species in regions with many geographical barriers or few?

Answer 5

many geographical barriers

Question 6

reproductive isolating between populations increases as what increases?

Answer 6

distances between them increases

Question 7

barriers to reproduction are what?

Answer 7

intrinsic
- separation itself is not a biological barrier

Question 8

sympatric speciation

Answer 8

• in geographically overlapping populations
• reproductive barrier isolates subset of pop

Question 9

what can sympatric speciation come from?

Answer 9

polyploidy, natural selection, sexual selection, habitat differentiation

Question 10

polyploidy

Answer 10

presence of extra sets of chromosomes due to accidents during cell division

Question 11

is polyploidy more common in plants or animals

Answer 11

plants

Question 12

autopolyploid

Answer 12

ind. w/ 2+ chromosome sets derived from single species

Question 13

allopolyploid

Answer 13

species w/ multiple chromosome sets derived from 2 dif species

Question 14

what crops are polyploids?

Answer 14

oats, cotton, potatoes, tobacco, wheat

Question 15

habitat differentiation

Answer 15

appearance of new ecological niches

Question 16

sexual selection

Answer 16

selection of mate

Question 17

hybrid zone

Answer 17

region in which members of different species mate and produce hybrids

Question 18

hybrids often have what compared with their parent species?

Answer 18

poor survival and reproduction

Question 19

when closely related species meet in hybrid zone…

Answer 19

1. reinforcement
2. fusion
3. stability

Question 20

reinforcement

Answer 20

strengthening reproductive barriers
- hybrids have less fitness than parent species
- rate of hybridization decreases
- reproduction barriers stronger for sympatric than allpatric

Question 21

fusion

Answer 21

weakening reproductive barriers
- hybrids fit as parent species
- can fuse into single species if gene flow great enough

Question 22

stability

Answer 22

continued formation of hybrid individuals

Question 23

speed of speciation

Answer 23

can occur rapidly or slowly

Question 24

broad patterns in speciation are studied using what?

Answer 24

fossil record, morphological data, molecular data

Question 25

punctuated equilibria

Answer 25

periods of apparent stasis punctuated by sudden change
- Eldredge and Gould

Question 26

range of interval between speciation

Answer 26

4,000 years to 40 million years

Question 27

how many genes change in speciation?

Answer 27

can be one or many

Question 28

macroevolution

Answer 28

cumulative effect of many speciation and extinction events