Chapter 16 - Population Genetics

Question 1

Population:

Answer 1

All individuals of same species living in a given geographical area

Question 2

Gene:

Answer 2

Discreet segment of DNA that codes for a particular trait
Ex: Hair Color; Skin Color

Question 3

Gene Pool:

Answer 3

All the genes of a population

Question 4

Allele Frequency

Answer 4

Relative proportion of each allele in a population
Population of pea plants were purple alleles, W, the allele frequency would be 100%
25 individuals, 50 alleles, 20/50 result in black fur, allele freq. = 0.40

Question 5

Key

Answer 5

Evolution is change of allele frequencies within a population over time/generations

Question 6

Hardy-Weinberg Principle

Answer 6

Allele frequencies and genotypes frequencies remain unchanged - no evolution!

Question 7

Examples of Non-Evolution

Answer 7

Changes in diet/exercise + weight

Question 8

Conditions for Hardy-Weinberg Principle

Answer 8

No mutation, no gene flow, no immigration, no emigration.
Very large population, completely random mating, no natural selection = no differential fitness.

Question 9

Gene Flow

Answer 9

Movement of alleles to/from another population. Rampant in modern humans. Plant population example: Pollen, Spores, Seeds, Wind, etc.

Question 10

Genetic Drift

Answer 10

Some random event that removes some alleles from a small population. Ex: Black and white rabbits, white rabbits are dominant. Genetic drift can allow all black rabbits to survive while all white are eliminated.

Question 11

Bottleneck

Answer 11

One cause of genetic drift. Population decreases due to an event resulting in allele decrease. Ex: northern elephant seals have reduced variation due to humans hunting them

Question 12

Founder Effect

Answer 12

Small portion of population “founds” new area. Examples: the Amish

Question 13

All genotypes are equally unsuccessful

Answer 13

Any trait that gives any advantage will have increased success.

Question 14

Survival of the Fittest

Answer 14

Herbert Spencer

Question 15

Success depends on

Answer 15

Survival and Reproduction

Question 16

Natural Selection favors…

Answer 16

allele with increased success. acts on phenotypes, but phenotypes and genotypes are closely linked

Question 17

Successful phenotypes…

Answer 17

Help an organism survive and reproduce in a specific environment

Question 18

Competition:

Answer 18

Struggle for scarce resources. Most severe between members of the same species and populations.

Question 19

Predator/Prey Interactions

Answer 19

Interactions so strong that they exert selection pressures on each other = co-evolution

Question 20

Sexual Selection

Answer 20

Selection that acts on traits that are used to acquire a mate.
Ex: Peacocks, the bigger the tail, the more frequently they mate.

Question 21

3 Effects of Natural Selection on Populations

Answer 21

Directional
Stabilizing
Disruptive

Question 22

Directional:

Answer 22

Favors individuals with one extreme of the bell curve

Question 23

Stabilizing

Answer 23

Favors individuals with the average trait, variation is reduced.