Evolution

Question 1

Microevolution

Answer 1

Changes in the distribution of heritable phenotypes within a population

Question 2

Requirements for evolutionary change

Answer 2

• heritable variation in phenotypes due to genetic variation
• A mechanism of change

Question 3

Phenotype

Answer 3

Observed characteristics ex hair color or eye color

Question 4

Population

Answer 4

Group of the same species living in the same area

Question 5

Why can’t individuals evolve

Answer 5

Evolution is seen in populations not individuals

Question 6

Genotypes of an individual does not change over a lifetime

Answer 6

Mutations occur in specific cells not in a whole organism

Question 7

Why is no individual perfect for their environment?

Answer 7

Evolution cannot lead to organisms perfectly suited for their environment

Question 8

Reasons for why evolutionary change cannot lead to organisms that are perfect for their environment

Answer 8

• Environmental conditions change
• traits have trad-offs
• constrained, limited or randomly introduced variation

Question 9

Name the 6 mechanisms for evolutionary change:

Answer 9

Mutations
Gene flow
Genetic drift
Natural selection
Artificial selection
Sexual selection

Question 10

Mutations

Answer 10

Source of new alleles, rarely if ever change allele frequency’s

Question 11

Genetic drift

Answer 11

Random sampling that changes populations alleles

Question 12

Gene flow

Answer 12

Movements between populations changes alleles

Question 13

Natural selection

Answer 13

Differences in survival and reproduction causes change in alleles

Question 14

Artificial selection

Answer 14

Human intervention, humans choose alleles to be passed on

Question 15

Sexual selection

Answer 15

Mate selection or competition for mates

Question 16

What mechanism favors trait that improve ability to reproduce?

Answer 16

Sexual selection

Question 17

Which two mechanisms can introduce new alleles?

Answer 17

Mutations and gene flow

Question 18

What mechanism can cause a new trait to occur for a reason?

Answer 18

NO mechanism can

Question 19

Genetic drift def

Answer 19

Changing frequency of alleles by chance event- change unpredictably
Random sampling= random fertilization

Question 20

Which mechanism influences all populations?

Answer 20

Genetic drift

Question 21

What population size is more likely to be altered by genetic drift?

Answer 21

Small populations are more likely to be significantly altered by genetic drift

Question 22

Bottle neck effect (genetic drift)

Answer 22

Loss of significant proportion of population leading to DECREASED genetic diversity

Question 23

Founder effect

Answer 23

A proportion of a population moves and forms a new population

Question 24

Bottleneck and founder effect can:

Answer 24

Cause significant changes in allele frequency quickly, because only a proportion of initial population is present due to loss/move

Question 25

Gene flow def:

Answer 25

Movement of individuals or gemates between populations that changes allele frequency to change

Question 26

3 factors of magnitude of change

Answer 26

- Different alldeles frequency - How many move in what direction - Duration of movement (long/short time)

Question 27

Natural selection def

Answer 27

Favors traits that improve ability to survive and reproduce (improves relative fitness)

Question 28

Relative fitness

Answer 28

Number of alleles passed on compared to others in population

Question 29

Adaptation

Answer 29

Increase relative fitness (dependent on environment)

Question 30

Directional selection

Answer 30

Favors ONE extreme (lower OR higher fitness) “or”

Question 31

Stabilizing Selection

Answer 31

Disfavors extremes (favors middle) “none”

Question 32

Disruptive Selection

Answer 32

Favors BOTH extremes (extremes more common) “BOTH”

Question 33

Sexual selection def

Answer 33

Favors traits that improve chances of getting a mate

Question 34

Two key points about sexual selection

Answer 34

- Must increase attractiveness to opposite sex - may decrease ability to survive

Question 35

Artificial selection def

Answer 35

Changes in allele frequency due to human intervention Humans choose best alt based on traits

Question 36

Artificial selection is the only mechanism:

Answer 36

With a goal

Question 37

Artificial selection does not…

Answer 37

Introduce new alleles Lead to adaptation