Darwin and microevolution

Question 1

What are the 4 premises of natural selection?

Answer 1

1. Overproduction
2. Heritable variation exists
3. Competition
4. Survivors reproduce

Question 2

Is Darwin’s principle of evolution, natural selection, random?

Answer 2

No it is not random.

Question 3

What is macroevolution?

Answer 3

Speciation, common descent (all beings are related to the 1st organism)

Question 4

What is microevolution?

Answer 4

Evolution of populations (because individuals do not evolve)

Question 5

Define population.

Answer 5

All organisms of a species

often used when referring to a local population

Question 6

Define gene pool.

Answer 6

All possible alleles within a population

-all alleles at all loci

Question 7

How do you know if evolution has occured?

Answer 7

A change in allele frequency.

Question 8

How do you calculate REAL genotype frequencies.

Answer 8

Take the real numbers ONLY!!!

Question 9

Real frequency of homozygous dominant =

Answer 9

(number of AA)/(total numbr of individuals)

Question 10

Real frequency of heterozygotes=

Answer 10

(number of Aa)/(total numbr of individuals)

Question 11

Real frequency of homozygous recessive=

Answer 11

(number of aa)/(total numbr of individuals)

Question 12

Real frequency of dominant allele=

Answer 12

(number of A)/(total numbr of alleles)

Question 13

Real frequency of recessive allele =

Answer 13

(number of a)/(total numbr of alleles)

Question 14

What is p in the Hardy-Weinberg equation?

Answer 14

Represents the EXPECTED frequency of the dominant allele

Question 15

What is q in the Hardy-Weinberg equation?

Answer 15

Represents the EXPECTED frequency of the recessive allele

Question 16

When will p + q = 1 and p2 + 2pq + q2 = 1

Answer 16

When a population is in equilibrium (not evolving)

Question 17

What is p2 in the Hardy-Weinberg equation?

Answer 17

Represents the EXPECTED frequency of the homozygous dominant genotype

Question 18

What is q2 in the Hardy-Weinberg equation?

Answer 18

Represents the EXPECTED frequency of the homozygous recessive genotype

Question 19

What is 2pq in the Hardy-Weinberg equation?

Answer 19

Represents the EXPECTED frequency of the heterozygous genotype

Question 20

What are the 5 Hardy-Weinberg conditions?

Answer 20

a. random mating
b. no mutations
c. no gene flow
d. large population
e. no selection

Question 21

What is used to determine expected p2, q2 and 2pq?

Answer 21

REAL ALLELE frequencies.

Question 22

What are the effects of non-random mating?

Answer 22

Does not affect allele frequencies but can change genotype and phenotype frequencies .

Question 23

What are the types of non-random mating?

Answer 23

1. Positive assortative mating: between physically similar individuals
2. Negative assortative mating: between physically opposite individuals
3. Inbreeding: between genetically related individuals

Question 24

What are the 4 mechanisms of micro-evolution?

Answer 24

Mutation
Gene flow
Genetic drift
Natural selection
= mechanisms that CHANGE allele frequencies

Question 25

Describe mutation.

Answer 25

Random change to DNA, source of diversity (new alleles), can be unfavorable/harmful/beneficial

Question 26

Describe gene flow.

Answer 26

Flow of alleles in and out of the population; migration between local populations, can ↑ genetic variation

Question 27

Describe genetic drift.

Answer 27

Effect of chance (random), quick reduction in pop size, ↓ genetic variation

Question 28

Explain the founder effect.

Answer 28

A small number of individuals establish (colonize) a new habitat and carry sample of alleles

Question 29

Explain the bottle neck effect.

Answer 29

Number of individuals in a population drastically reduced (drastic murder); survival due to chance, survivors unrepresentative of original population

Question 30

Describe natural selection.

Answer 30

• Not random
• Acts on PHENOTYPE of the organism
• Interaction w/env.
• Selected for/against
• Individuals DO NOT evolve, populations evolve

Question 31

Why does natural selection require variation?

Answer 31

1. To be created: mutations, recombination, sexual reproduction
2. To be maintained: heterozygosity (hides), heterozygous advantage (fitter), neutral variation

Question 32

Describe fitness.

Answer 32

The ability (of individuals or population) to leave viable offspring – survival does not always guarantee reproductive success.
Determined by an interaction of many genes
Fittest individuals make a greater contribution to the gene pool

Question 33

What is sexual selection?

Answer 33

A type of natural selection or non-random mating and a selection for characteristics that increase chances of mating

Question 34

What is the limitation of females in sexual selection?

Answer 34

Produce few, large eggs limited by number of eggs they can support (provide food)

Question 35

What is the limitation of males in sexual selection?

Answer 35

Produce many, small sperm

imited by access to females

Question 36

Give 3 examples of “males compete, females choose”

Answer 36

1. male-male competition (fighting)
   leads to males larger
2. male offer nuptial gifts (food) leads to larger size and # of eggs
3. male displays ornaments and/or courtship behaviors

Question 37

What are the 3 modes of selection?

Answer 37

1. Directional selection
2. Stabilizing selection
3. Disruptive selection

Question 38

What is directional selection?

Answer 38

Selects phenotypes at one extreme of distribution

Question 39

What is stabilizing selection?

Answer 39

Selection for intermediate phenotype

Question 40

What is disruptive selection?

Answer 40

2 or more extreme phenotypes are favored over intermediate