Chapter 13: Processes of Evolution

Question 1

What is the hardy-weinberg equation?

Answer 1

p2 + 2pq + q2 = 1

Question 2

What are the two equations that can be used to calculate allele frequencies?

Answer 2

p + q = 1

p = [2N(AA) + N(Aa)] / 2N

q = [2N(aa) + N(Aa)] / 2N

Question 3

Allele frequencies(i.e. A or a) measure the amount of _________________(1) in a population.

Answer 3

(1) genetic variation

Question 4

______________________(1) show how such variation is distributed among members of the population.

Answer 4

(1) genotype frequencies (i.e. Aa, aa, AA)

Question 5

Allele and genotype frequencies provide information about _________________________(1).

Answer 5

(1) a population’s genetic structure

Question 6

What is Hardy-Weinberg equilibrium? What are the five conditions of hardy Weinberg equilibrium?

Answer 6

hardy-weinberg equilibrium is a model in which allele frequencies do not change across generations.

5 requirements
1. Random mating
2. Large population size
3. No mutation
4. No gene flow
5. No selection of genotypes

Essentially, NO EVOLUTIOn

Question 7

Since population in nature never meet the conditions of hardy-weinberg equilibrium, the model is only useful for _________________________(1)

Answer 7

(1) Predicting approximate genotype frequencies of a population

Hardy-weinberg equilibrium acts as a constant that we can constantly compare evolutionary changes to. This helps us identify mechanisms of evolutionary change

Question 8

What is stabilizing selection?

Answer 8

Favours average individuals(steep curve in the middle)

Question 9

What is directional selection?

Answer 9

favour individuals that vary in one direction from the mean, favours one extreme, entire bell curve shifts to the left or right(steepness does not change)

Question 10

What is disruptive selection?

Answer 10

favours both extremes, bimodal

Question 11

____________________(1) reduces variation in populations but does not change _________________(2). It is often called ________________(3) meaning selection against any __________________(4).

Answer 11

(1) Stabilizing selection
(2) the mean
(3) purifying selection
(4) deleterious mutations

Question 12

For a single locus, _____________________(1) may favour a particular variant — __________________(2) for that variant

Answer 12

(1) directional selection
(2) positive selection

Question 13

___________________(1) selection results in increased variation in the population.

Answer 13

(1) disruptive selection

Question 14

What is a polymorphism?

Answer 14

the idea of having the same species start to have different phenotypes so that they can live in their individual niches/habitats

Question 15

What is evolutionary theory?

Answer 15

A scientific body of work concerned with studying the mechanisms that cause evolutionary change in populations

Question 16

What did Darwin do for evolutionary theory?

Answer 16

• The first person to articulate a theory of evolutionary change based on scientific study and observation

-Provoked by a 5-year voyage around the world on the HMS beagle

• Darwin studied the Galapagos islands, and found that many organisms living on the islands were unique from others in the world
• Organissms differed from island to island

Question 17

What was Darwin’s hypothesis?

Answer 17

many organisms originally came to the islands from the mainland and each island presented a unique living environment to which organisms had to adapt in order to survive and reproduce.

Question 18

What is sexual selection?

Answer 18

When individuals of one sex mate preferentially with particular individuals of the opposite sex rather than at random. There may be a trade-off between attracting mates(more likely to reproduce) and attracting predators(less likely to survive). this is an example of non-random mating

Question 19

What is the founder effect?

Answer 19

A small group of population is speerated from the rest. Few individuals colonize a new area. Less genetic variation

Question 20

What is a bottleneck?

Answer 20

a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities. Less genetic variation

Question 21

What is genetic drift?

Answer 21

Changes in allele frequencies from one generation to the next due to random sampling, affects both large and small populations.

• Types of genetic drift are bottleneck and founder effect

Question 22

What is an adaptation?

Answer 22

A favoured trait that spreads through a population by natural selection.

Question 23

What were Darwin’s theories?

Answer 23

1. Species change over time
2. Divergent species share a common ancestor(descent with modification)
3. the mechanism that produces change is natural selection.

Question 24

Who was Alfred Russel Wallace?

Answer 24

Studied biodiversity in SE asia, wrote a paper and Charles Darwin agree with the ideas in this paper

Question 25

What is natural selection?

Answer 25

Individuals best adapted to a given environment contribute more offspring to succeeding generations and survive better than others do. the differential survival and reproduction of individuals is due to variation of their traits. As more and more individuals of a population acquire new adaptive traits, the characteristics of the entire population evolve.

Question 26

What is a gene pool?

Answer 26

Sum of all copies of all alleles at all loci in a population

Question 27

What is allele frequency?

Answer 27

proportion of each allele in the gene pool

Question 28

What is genotype frequency?

Answer 28

Proportion of each genotype among individuals in the population

Question 29

Many of Darwin’s observation of variations and selection came from ____________________________(1). Darwin bred ________________________(2) and recognized similarities between selection by breeders and selection in nature. In both cases, selection simply increases the ________________________(3) from one generation to the next.

Answer 29

(1) domesticated plants and animals
(2) pigeons
(3) frequency of the favoured trait