Chapter 10: Population & Evolutionary Genetics

Question 1

Evolution

Answer 1

Change in allele frequency of a population

Question 2

Charles Darwin

Answer 2

Origin of Species (1859)

Question 3

Take a population (5,000 fruit flies)

Answer 3

Average survival without food (20 hours)

Question 4

Starve until 80% of flies

Answer 4

Dies

Question 5

Feed survivors, allow them to

Answer 5

Breed

Question 6

Starve offspring until

Answer 6

80% dies, takes longer than parent generation (average survival without food: 23 hours)

Question 7

Repeat for many generations, selecting for

Answer 7

Starvation survival, generation 60: average survival: 160 hours

Question 8

How does evolution occur? How do allele frequencies change in population?

Answer 8

1. Mutation
2. Genetic drift
3. Migration
4. Natural selection

Question 9

Mutation

Answer 9

Change to genome

Question 10

Mutation are randome events, although they can be

Answer 10

Encouraged (mutagens)

Question 11

Mutations are the root of all

Answer 11

Genetic variation

Question 12

Most mutation have negative effect by the two following:

Answer 12

1) Generally create non-functioning genes
2) If mutation creates functional gene, may or may not make the organism more fit

Question 13

Genetic drift

Answer 13

Random changes in allele frequency

Question 14

Unlike natural selection, the change does not impact

Answer 14

Fitness directly; it is just which allele combination are inherited from parents

Question 15

Genetic drift can cause traits to

Answer 15

Increase or decrease in a population and acts more strongly on small population

Question 16

Genetic drift can lead to

Answer 16

Allele fixation: frequency of an allele = 100%
1) No variability
2) Genetic drift can lower variation

Question 17

Genetic drift examples:

Answer 17

1) Founder effect
2) Bottlenecks

Question 18

Founder effect

Answer 18

New, isolated populations exhibit different allele frequencies than original population

Question 19

Bottlenecks

Answer 19

After large die off, survivors may have different allele frequencies than original population

Question 20

Gene flow

Answer 20

Movement of individuals into other populations

Question 21

Gene flow can introduce (or reintroduce) alleles to

Answer 21

Separated populations

Question 22

Natural selection

Answer 22

Selection of traits (alleles) improving an organism chance of surviving and producing offspring (fitness)

Question 23

Natural selection not directly removing

Answer 23

Unwanted genes

Question 24

Natural selection origin of

Answer 24

Survival of the fittest

Question 25

Natural selection requires 3 conditions

Answer 25

1) Variation in the trait 2) Heritability 3) Differential reproductive success

Question 26

Three types of natural selection:

Answer 26

1) Stabilizing 2) Directional 3) Disruptive

Question 27

Stabilizing

Answer 27

Favors the average/most common phenotype

Question 28

Directional

Answer 28

Favors an extreme phenotype

Question 29

Disruptive

Answer 29

Favors more than one phenotype

Question 30

Sexual selection

Answer 30

Form of natural selection specifically acting on traits that increase the ability to gain mating opportunities

Question 31

Sexual selection may

Answer 31

Decrease lifespan, but increase reproductive output

Question 32

Sexual selection leads to

Answer 32

Sexual dimorphism

Question 33

How do we get adaptations?

Answer 33

Populations typically have some variation in traits; all possible alleles form the gene fool

Question 34

Adaptation key point:

Answer 34

The variation in phenotypes (dependent on the gene tool) is what natural selection acts upon

Question 35

Different alleles:

Answer 35

Variation in phenotypes = adaptations

Question 36

Genetic variation

Answer 36

1) Most populations exhibit genetic variability 2) No variation = no evolution