Chapter 17: Evolution of Populations

Question 1

What is an allele?

Answer 1

different version of a gene

Question 2

What is a gene pool?

Answer 2

all the alleles for each gene that are present in a population

Question 3

In genetic terms, what is evolution?

Answer 3

change over time in relative frequency of alleles in a population

Question 4

What is a polygenic trait?

Answer 4

trait that is controlled by more than one gene

Question 5

What is a single-gene trait?

Answer 5

trait that is controlled by one gene

Question 6

What does directional selection show?

Answer 6

shift of a trait in a particular direction

Question 7

What does stabilizing selection show?

Answer 7

individuals in the center have a higher fitness level than individuals on the ends

Question 8

What does disruptive selection show?

Answer 8

individual on the ends have a higher fitness level than those towards the center and SPECIATION

Question 9

What is genetic drift?

Answer 9

random change in allele frequencies

Question 10

What is a genetic bottleneck?

Answer 10

drastic decrease in the size of a population (decrease in genetic variation)

Question 11

What do smaller populations decrease?

Answer 11

variation

Question 12

What is founder effect?

Answer 12

type of genetic drift when a few individuals colonize an new habitat the may carry a different allele frequency from the main population

Question 13

Are offshoot populations representative of the population they came from?

Answer 13

No

Question 14

What is genetic equilibrium?

Answer 14

allele frequencies of a population do not change

Question 15

What is the Hardy-Weinberg Principle?

Answer 15

allele frequencies do not change unless pressures are introduced into the population

Question 16

What are the five pressures of the Hardy-Weinberg Principle?

Answer 16

1. Sexual selection
2. Small population
3. Immigration/Emigration
4. Mutations
5. Natural selection

Question 17

What is speciation?

Answer 17

formation of a new species from an existing

Question 18

When do you know when speciation has occurred?

Answer 18

populations can’t interbreed and produce fertile offspring

Question 19

What is the key to speciation?

Answer 19

reproductive isolation

Question 20

What are the three ways reproductive isolation can occur?

Answer 20

geographic isolation, behavioral isolation, and temporal isolation

Question 21

What is geographic isolation?

Answer 21

separation by geographic barriers

Question 22

What is behavioral isolation?

Answer 22

separation of courtship/behaviors

Question 23

What is temporal isolation?

Answer 23

separation of reproductive seasons