unit 7- evolution

Question 1

evolution

Answer 1

change in the genetic makeup of a population over time; descent of modification

Question 2

natural selection

Answer 2

individuals that have certain traits tend to survive and function at higher rates other than individuals bc of those traits

Question 3

fitness

Answer 3

the ability to survive and reproduce

Question 4

two theory based on natural selection

Answer 4

1. traits are heritable
2. more offspring is produced than survived

Question 5

adaptations

Answer 5

inherited characteristics of an organism that enhances their survival and reproduction

Question 6

mutations can be

Answer 6

harmful, beneficial, neutral

Question 7

examples of random occurrences

Answer 7

1. migration/gene flow
2. mutations
3. genetic drift

Question 8

genetic drift

Answer 8

a change in events that causes a change in allele frequency from one generation to the next

Question 9

two types of genetic drift

Answer 9

bottleneck effect: when a population is reduced by a non-selective disaster (floods, fires, hurricanes, hunting)
founder effect: when some become isolated from a large population and establish a small population with a gene pool that differs from the large population

Question 10

gene flow

Answer 10

the transfer of alleles into or out a population due to fertile individuals or gametes

Question 11

5 conditions that meet Hardy Weinberg

Answer 11

1. no mutations
2. no gene flow
3. no natural selection
4. random mating
5. large population size

Question 12

evidence of evolution

Answer 12

1. fossils
2. comparative morphology
3. biogeography

Question 13

vestigial structures

Answer 13

structures with little or no use

Question 14

homologous structures

Answer 14

same structure but different function (common ancestor)

Question 15

analogous structures

Answer 15

different structure but same functions (different ancestor)

Question 16

to determine evolutionary relationships scientist use

Answer 16

• DNA
• fossils
• homologous structures

Question 17

allopatric vs sympatric

Answer 17

allopatric: physical barrier divides population (often caused by natural disasters)
sympatric: a new species evolves while still inhibiting the same geographic region as the ancestral species

Question 18

describe and list the 5 prezygotic barriers

Answer 18

1. habitat isolation: species live in different areas and unable to mate
2. temporal isolation: species breed at different times of the year or season
3. behavioral isolation: unique behavioral patterns separate species
4. mechanical isolation: the reproductive anatomy does not fit with another species
5. gamete isolation: do not allow for the egg and sperm to fuse

Question 19

3 postzygotic barriers

Answer 19

1. reduced hybrid viability: impair the hybrids development of survival
2. reduced hybrid fertility: hybrid are not fertile (can’t reproduce)
3. hybrid breakdown: hybrid of first gen may be fertile but when they mate again their offspring will be sterile

Question 20

puntuated equilibrium vs gradualism

Answer 20

PE: evolution occurs rapidly after a period of stasis (no change over long periods of time)
gradualism: evolution occurs slowly over many years

Question 21

divergent evolution

Answer 21

groups with the same common ancestor evolve differences resulting in the formation of a new species

Question 22

convergent evolution

Answer 22

two different species develop similar traits