BIO356 Final Exam Practice

The Hardy-Weinberg equilibrium (HWE) law can be used to

calculate allele frequencies when dominance occurs

The Hardy-Weinberg equilibrium (HWE) law assumes that

individuals in a population are mating at random

Which one of the following does NOT directly change the allele frequencies in a population?

random mating

In the context of population genetics, the term mutation refers to the conversion of

one allelic form of a gene into another allelic form

A mutation rate of 10^-4means that there is:

one new mutant allele per 10,000 gametes

Do recurrent mutation generates new novel alleles?

False

Genetic drift is

random changes in the allele frequencies of a population brought about by errors in the sampling of genetic variation from one generation to the next

Genetic drift results in

reduced genetic variation within a population and divergence of the genetic composition of different populations

Genetic drift can result in the loss of selectively-neutral or disadvantageous 

alleles from populations, but not of alleles favoured by selection.

False

The effects of genetic drift are likely to be most pronounced in a population with a genetically effective size of

50 individuals

Gene flow is

an exchange of genetic information among the populations of a species and causes the genetic composition of the populations to converge.

Which of the following is a continuous trait?

Egg weight in chickens

Which of the following genetic diseases in humans is an example of a threshold trait?

Type II (adult onset) diabetes

Adzuki bean beetles can feign death or fly away in response to predators. The intensity of death feigning and flying ability are both quantitative traits and have a genetic correlation of negative 0.657.  If beetles are selected for intensity intensity of death feigning, then on average the flying ability of beetles in the population will likely

decrease due to the negative genetic correlation.

True or False: As a trait responds to selection, the narrow-sense heritability, additive genetic variance and the mean value of the trait will increase.

False

Heritability is a measure of the

source of differences among individuals in a population.

Directional selection

selects for one extreme of a continuous trait and changes the average value of the trait.

Which of the following is NOT one of the four postulates of natural selection?

an adaptation is a trait that increases the fitness of its possessor

Disruptive selection is where the extreme values of a trait are favoured and does not change the average value of the trait.

True

In Batesian mimicry

a mimic gains in fitness by resembling a distasteful model and the fitness benefit is highest when the mimic is rare.

True or False: Negative frequency dependent selection describes a situation where the fitness of a trait increases as the frequency of the trait in the population increases.

False

In a population of Drosophila, individuals with intermediate numbers of sternoplueral bristles have a selective advantage compared to those with a very large or very small number of bristles. This is an example of

stabilising selection

A theoretical definition of a species is called a 

Species Concept

The term 'phenotypic cohesion' refers to the

overall similarity of the individuals of a species.

The Biological Species Concept states that a species is a

set of interbreeding organisms that are reproductively isolated from those in other such sets.

reticulate evolution

A reticulate network of gene exchange among closely related morphospecies is called a

The Biological Species Concept

does not apply to either Archaea or Eubacteria.

Which of the following species concepts underlies most models of speciation?

Biological Species Concept

sympatric speciation

A model of speciation where a new species arise within the ancestral population via the evolution of intrinsic barriers to gene exchange

Allopatric speciation by peripheral isolation

A model of speciation where a new species evolves from a small population isolated at the edge of the ancestral species range

Parapatric speciation

A model of speciation where reproductive isolation evolves between overlapping or abutting populations with limited gene exchange

Ecological speciation

A model of speciation where a new species evolves as a result of ecologically-based divergent selection

Which of the following types of speciation leads to congruent patterns of diversification in many taxa?

allopatric by subdivision

Sympatric speciation is controversial for

gradual models of speciation because the incipient species are in contact and interbreeding can breakdown the genetic divergence between them.

Which of the following is an example of a behavioural isolating mechanism?

Sula nebouxii (blue-footed booby) and Sula sula (red-footed booby) have different courtship displays. 

The F₁ hybrids of lions and tigers are often viable and fertile but F₂ hybrids and backcrosses are typically inviable and/or sterile. The term used to describe this situation is

hybrid breakdown.

Reinforcement is where natural selection favours an increase in

prezygotic isolation when partial postzygotic isolation is in place. 

inbreeding

A breeding system where matings between relatives are more frequent that would be expected due to randomness

The genetic consequences of inbreeding are

an increase in homozygosity in both individuals and populations.

Inbreeding is measured via the inbreeding coefficient (F), which measures the probability of

autozygosity

Species X consists of a series of populations.  The individuals in these populations are mating at random.   On this basis, which of the following populations of species X most likely has the highest amount of inbreeding? 

Population C with a (genetically effective) size of 100.

Inbreeding depression

A decrease in fitness associated with inbreeding

The partial dominance hypothesis states that inbreeding depression is due to 

increased expression of deleterious recessive alleles.