Microevolution EW

Question 1

What are the 4 process of microevolution?

Answer 1

Genetic drift, mutation, gene flow, and natural selection

Question 2

What is the difference between micro and macro evolution?

Answer 2

Microevolution is a change in allele frequency in a population or species across generations, and macroevolution goes above the species level, and focuses on variation among species and covers a longer period of time.

Question 3

Define panmixia

Answer 3

Panmixia is random mating within a population. A population that mates randomly is described as panmictic.

Question 4

Why is mating usually non-random? (4 reasons)

Answer 4

1. Relatives may mate more/less often than expected (inbreeding vs outbreeding)
2. Individuals may self-fertilize more often than expected
3. Individuals may mate more than expected with other individuals with similar or different phenotypes (assortative mating vs disassortative mating)

Question 5

What is the difference between assortative mating and disassortative?

Answer 5

Assortative mating is when individuals tend to procreate with other individual with similar phenotypes, and disassortative mating is the opposite.

Question 6

What effect does inbreeding have on zygostiy?

Answer 6

Inbreeding causes higher rates of homozygosity.

Question 7

Define inbreeding depression

Answer 7

Inbreeding depression is a loss of fitness in populations as a result of inbreeding

Question 8

What are the two hypotheses related to inbreeding depression?

Answer 8

The dominance hypothesis and heterozygote advantage.

Question 9

Explain the dominance hypothesis.

Answer 9

The dominance hypothesis describes that deleterious alleles are generally recessive, and the increased homozygosity associated with inbreeding will lead to a higher rate of expression of these phenotypes.

Question 10

Explain the heterozygote advantage.

Answer 10

The heterozygote advantage describes a situation where there is a specific beneficial phenotype associated with heterozygosity, which is less common in an inbred population.

Question 11

Name the 6 mechanisms of inbreeding avoidance.

Answer 11

1. Kin recognition
2. Dispersal
3. delayed maturation/reproductive succession
4. extra pair copulations (monogamy)
5. self incompatibility (hermaphrodites)
6. physical or temporal separation of reproductive organs (hermaphrodites)

Question 12

What is heterosis (hybrid vigor)?

Answer 12

It is an increase in fitness of outbred individuals in relation to non-outbred individuals. Does not occur if there is a local adaptation

Question 13

Why might DNA mutate?

Answer 13

Error in replication/recombination, error in DNA repair, error from mutagens

Question 14

What is the ultimate source of genetic variation? Why?

Answer 14

Mutation. This is because the other processes of evolution do not create new varieties of allele.

Question 15

When are mutations transmissible?

Answer 15

When the mutations appear on the germ line.

Question 16

What are the two types of small scale mutation? (with descriptions)

Answer 16

Substitution (when a single nucleotide is replaced with another, can be silent or replacement depending on the affect on amino acid affect)
Insertion/Deletion (When one or more nucleotides are added or removed generally producing more severe consequences)

Question 17

What is large scale mutation?

Answer 17

A change in chromosomal structure such as a translocation, inversion, or duplication

Question 18

Why is mutations effect on allele frequency generally weak?

Answer 18

Because there is a low mutation rate in individuals.

Question 19

Are deleterious or beneficial mutations more common?

Answer 19

Deleterious

Question 20

Why will some deleterious or neutral mutations fix in a population?

Answer 20

Genetic drift is random and may carry a sample throughout the population. Deleterious alleles may be recessive and “hidden” from phenotype expression.

Question 21

What is gene flow?

Answer 21

The movement of alleles between populations.