Chapter 19 Microevolution

Question 1

Micro evolution

Answer 1

minor differences in allele frequency within a population of the same species

Question 2

Population

Answer 2

A group of individuals from the same species living together in a particular area at the same time (ex: californians, new yorkers)

Question 3

Population genetics

Answer 3

The study of the diversity (allele differences) between members of a population

Question 4

Why is allele frequency important?

Answer 4

The types of alleles in a population will define the types of genotypes in the population. Thus, the frequency of a specific allele will affect the frequency of the genotypes in a population

Question 5

What needs to happen for microevolution to occur?

Answer 5

A change in these allele frequencies within populations over time

Question 6

Hardy Weinberg Equilibrium

Answer 6

In a population mating at random (without evolutionary processes) allele frequency will remain constant

Question 7

What are the conditions required in population to meet the Hardy Weinberg Equilibrium?

Answer 7

• random mating
• no selection (meaning all genotypes are equally selected for)
• no mutations
• no immigration
• large gene pool

Question 8

Are the required conditions ever truly met to maintain HWE?

Answer 8

No, deviations from HWE indicate that evolution has taken place

Question 9

Random mating

Answer 9

occurs when any male/female has an equal opportunity to mate, regardless of phenotype

Question 10

Assortative mating

Answer 10

Individuals with SIMILAR phenotypes mate more frequently with each other, than with individuals of different phenotypes

Question 11

Disassortative mating

Answer 11

Individuals with DIFFERENT phenotypes mate more frequently with each other, than with individuals of similar phenotype

Question 12

Sexual selection

Answer 12

Adaptive changes in males and females lead to an increased ability to secure a mate (females choosing males based on increased fitness, males have traits that help them outcompete other males for mates)

Question 13

Good genes hypothesis

Answer 13

Females choose males on the basis of traits that improve the chance of survival

Question 14

Runaway hypothesis

Answer 14

Females choose mates on the basis of traits that improve male appearance

Question 15

Sexual dimorphism

Answer 15

Males and females are morphologically distinct

Question 16

Directional selection

Answer 16

When natural selection favors a single allele (allele frequency continuously shifts in one direction)

Question 17

Disruptive selection

Answer 17

Individuals at the extremes contribute more offspring than those in the center

Question 18

Stabilizing Selection

Answer 18

Extreme values of a character are selected against

Question 19

Mutation

Answer 19

Raw material for evolutionary change (Provide new alleles)

Question 20

Gene flow

Answer 20

Movement of alleles between populations

Question 21

Migration

Answer 21

Continued gene flow diminishes genetic divergence between populations (If population has decreased gene flow, gene pools become different over time)

Question 22

Effective population size

Answer 22

Number of individuals that contribute offspring to the next generation (small populations have small effective population size and increased the likelihood of random sampling error)

Question 23

Genetic Drift

Answer 23

The genetic change in a population due to only random sampling error in of alleles

Question 24

What are the two types of genetic drifts?

Answer 24

The bottleneck effect
The founder effect

Question 25

The founder effect

Answer 25

A new population is started from just a few individuals. Alleles carried by these founders are dictated by chance

Question 26

Bottleneck effect

Answer 26

a random event prevents a majority of individuals from entering the next generation from a natural disaster or etc. Alleles carried by next generation are dictated by chance