Ecological Genetics

Question 1

What is the term for non-genetic variation?

Answer 1

Phenotypic plasticity

Phenotypic plasticity refers to the ability of an organism to change its phenotype in response to environmental conditions.

Question 2

What are the major sources of genetic variation?

Answer 2

Mutations and recombination of genes

Mutations introduce new alleles, while recombination mixes existing alleles during reproduction.

Question 3

What are the five assumptions of Hardy-Weinberg Equilibrium?

Answer 3

• Mating is random
• Mutation do not occur or are not associated with a particular allele
• A closed population (no gene flow)
• Population size is large enough to avoid random drift
• No natural selection occurs

These assumptions help maintain allele frequencies in a population over generations.

Question 4

What happens to genotype frequency in Hardy-Weinberg Equilibrium?

Answer 4

It is maintained in each F2 generation

This means that the genetic structure of the population remains stable under ideal conditions.

Question 5

What effect does genetic drift have on small populations?

Answer 5

Small populations are vulnerable to genetic drift

Genetic drift can lead to the loss of alleles and reduced genetic diversity.

Question 6

What is an example of natural selection observed in populations?

Answer 6

Insecticide or drug resistance

Populations can adapt to pressures, leading to increased survival of resistant individuals.

Question 7

What type of selection favors the average expression of a phenotype?

Answer 7

Stabilizing selection

Stabilizing selection reduces variation and maintains the status quo for a particular trait.

Question 8

What type of selection favors one extreme type?

Answer 8

Directional selection

This type of selection shifts the population mean towards one extreme of the trait distribution.

Question 9

What type of selection favors both extreme phenotypes?

Answer 9

Disruptive selection

Disruptive selection can lead to speciation as it promotes the survival of two or more contrasting phenotypes.

Question 10

What is a cline?

Answer 10

Gradual variation in phenotypes over a geographic region

A cline reflects the continuous change in phenotypic traits across different environments.

Question 11

What are local populations with sufficiently discontinuous variation called?

Answer 11

Ecotypes

Ecotypes are adapted to specific environmental conditions, leading to distinct phenotypes.

Question 12

What is adaptive radiation?

Answer 12

Process by which one species gives rise to multiple species as different niches are exploited

Adaptive radiation often occurs in environments with diverse ecological opportunities.

Question 13

What is the genetically effective population size denoted as?

Answer 13

Ne

Ne represents an ideal population size that experiences the same level of genetic drift as a real population.

Question 14

What can occur if a genetic bottleneck is experienced?

Answer 14

The Ne of the newly expanding population will be considerably reduced

A genetic bottleneck drastically reduces genetic diversity, which can affect the population’s adaptability.

Question 15

Why are many weed populations not vulnerable despite being genetically depauperate?

Answer 15

• Phenotypic plasticity
• Breeding systems of many weed species are selfing

These traits allow weeds to persist and successfully reproduce in varied environments.

Question 16

Fill in the blank: The advantage of selfing in small populations is that they can persist without the need for _______.

Answer 16

pollination

Selfing allows for reproduction even when pollinators are scarce.