Chapter 11: The Evolution of Populations

Question 1

Gene Pool

Answer 1

Combined alleles of all individuals will be able to survive a change in environment

Question 2

Allele Frequency

Answer 2

Measure of now common a certain allele is in a population

Question 3

Normal Distribution

Answer 3

Frequency is highest near the mean value and decreases toward the extremes for a given trait

Question 4

Microevolution

Answer 4

The observable change in the allele frequencies of a population over time

Question 5

Directional Selection

Answer 5

Favors phenotypes at one extreme of a traits range
- Causes a shift

Question 6

Stabilizing Selection

Answer 6

Intermediate phenotype is favored and becomes more common

Question 7

Disruptive Selection

Answer 7

Both extreme phenotypes are favored
- The intermediate phenotypes are selected against

Question 8

Gene Flow

Answer 8

Exchange of genes between population

Question 9

Genetic drift

Answer 9

Change in allele frequencies due to chance

Question 10

Bottleneck effect

Answer 10

Occurs after an event wipes out a large number of the population
(i.e. cheetahs / elephant seals)

Question 11

Founder Effect

Answer 11

Occurs after a small number of individuals colonize a new area
(i.e. birds carry seeds to a new location, and flowers start a new population)

Question 12

Sexual selection

Answer 12

Occurs when certain traits increase mating success
- Helps ensure that more favorable traits will be passed on

Question 13

Reproductive Isolation

Answer 13

When members of different populations cannot longer mate successfully

Question 14

Speciation

Answer 14

The rise of 2 or more species

Question 15

Behavioral Isolation

Answer 15

Isolation caused by differences in courtship or mating behaviors

Question 16

Geographical Isolation

Answer 16

Physical barriers that divide a population into 2 groups

Question 17

Temporal Isolation

Answer 17

Timing prevents reproduction between populations

Question 18

Convergent Isolation

Answer 18

Evolution towards similar characteristics in unrelated species
- Analogous

Question 19

Divergent Isolation

Answer 19

When closely related species evolve in different directions
- Homologous

Question 20

Coevolution

Answer 20

The process in which two or more species evolve in response to changes in each other
- Can be beneficial or competitive

Question 21

Extinction

Answer 21

The elimination of a species from Earth

Question 22

3 types of natural selection (w/ examples)

Answer 22

Directional Selection: The fluctuation of light and dark peppered moths (went from one extreme to the other)
Stabilizing Selection: Birth weight (the middle of being too small or being too big is favored)
Disruptive selection: Short tails help animals run form predators and long tails are good for balance in trees (both extremes favored and the middle ground is not preferred)

Question 23

What’s the difference between Gene Flow and Genetic Drift?

Answer 23

Gene flow is the movement of alleles
Genetic Drift is the change of allele due to chance

Question 24

What are the two main types of genetic drift?

Answer 24

Bottleneck Effect
Founder Effect

Question 25

What is the process of sexual selection?

Answer 25

Display or Competition for mating
- Male Bighorn Sheep fight
Whoever wins gets the mate

Question 26

5 factors of Hardy-Weinberg Equilibrium

Answer 26

1.) Very large population
2.) No Immigration or Emigration
3.) No mutations
4.) Random Mating
5.) No Natural Selection

Question 27

5 factors of evolution

Answer 27

1.) genetic Drift
2.) Gene flow
3.) Mutation
4.) Sexual Selection
5.) Natural Selection

Question 28

Examples of each type of isolation

Answer 28

Behavioral: Eastern/Western Meadowlark songs differ
Geographical: A mountain range separating 2 types of goats
Temporal: Two species of frogs live int he same forest, but one reproduces in January and one reproduces in March