Lecture 2

How do alleles influence the traits of organisms?

A

Alleles are responsible for the physical appearance of organisms.

B

Alleles determine the specific blood-type carbohydrate on the surface of red blood cells in humans.

C

Each individual carries all the possible alleles for a particular gene.

D

Alleles are specific genes that determine an individual's traits.

B

In the context of the Hardy-Weinberg principle, what does the equation p + q = 1 signify?

A

It stands for the total genetic variation in a population.

B

It signifies the number of different alleles present in a population.

C

It represents the equilibrium of genotype frequencies in a population.

D

It signifies the mathematical model for mutation rates in a population.

A

How is evolution defined in population genetics?

A

It is a change in the population's genetic makeup influenced by natural selection.

B

It is the process where certain alleles become more widespread than others.

C

It is the alteration of the allele frequency within a population over time.

D

It is the spreading of a beneficial allele throughout the population.

C

What is it called when an event leads to a change in allele frequency in a non-representative portion of a population?

A

Natural Selection

B

Genetic Drift

C

Founder Effect

D

Genome Change

C

What effect does gene flow have on a population?

A

It stabilizes the gene structure of the population.

B

It introduces new genetic variation to the population.

C

It increases the size of the population.

D

It decreases the number of different alleles in the population.

B

What factors are influential in determining phenotypic variations within a population?

A

Genetic structure and the environment

B

Size and location

C

Predation and competition within the species

D

Population's age and health status

A

What is the impact of the bottleneck effect on a population's genetic structure following a natural disaster?

A

The survivors' genetic structure remains unchanged.

B

The survivors' genetic structure becomes the entire population's genetic structure.

C

The population's genetic structure becomes identical to the pre-disaster population.

D

The survivors' genetic structure is discarded and a completely new one is adopted.

B

How does gene flow influence the genetic structure of a population?

A

Gene flow decreases genetic variation within a population by preventing migration.

B

Gene flow introduces new genetic variation by allowing alleles to move between populations through migration.

C

Gene flow only occurs in animal populations, like lions, but does not affect plant populations.

D

Gene flow ensures that all populations remain genetically identical over time.

B

What type of natural selection is most likely occurring in a mouse population in the woods where the ground is a consistent shade of brown?

A

Directional selection

B

Disruptive selection

C

Sexual selection

D

Stabilizing selection

D

What is likely to happen if a substantial environmental change impacts a population's habitat?

A

The population will remain static in phenotype.

B

Every individual in the population will instantly change to adapt.

C

The population will undergo directional selection, shifting genetic variability towards a new, fit phenotype over time.

D

Predators will not be able to spot the population.

C

What is one scenario in which diversifying selection might occur?

A

It occurs when only one distinct phenotype has an advantage for natural selection.

B

It happens when middle-sized animals are selected over both small and large animals.

C

It ensues when environmental changes favor only one end of the phenotypic spectrum.

D

It can take place when environmental changes favor individuals on either end of the phenotypic spectrum.

D

Which type of natural selection leads to increased genetic variability by favoring two or more distinct phenotypes?

A

Stabilizing selection

B

Directional selection

C

Diversifying selection

D

Sexual selection

C

Which best describes the evolution of similar traits in species that do not share a recent common ancestry?

A

Divergent evolution

B

Convergent evolution

C

Natural selection

D

Adaptation evolution

B

What is the primary focus of evolution in the context of genetic change in a population?

A

Evolution refers to the physical changes that occur in individuals over their lifetime due to environmental factors.

B

Evolution is the change in a population's genetic makeup over generations, influenced by the differential reproduction of individuals with certain alleles.

C

Evolution only occurs when a species undergoes dramatic physical transformations in response to environmental pressures.

D

Evolution is the process by which individual organisms adapt to their environment and change their traits within a single generation.

B

What could be a potential process for sympatric speciation to occur?

A

Mutation in allele frequency

B

Geographic separation of individuals

C

Occurrence of polyploidy due to chromosomal error

D

Reduction in genetic diversity

C

What is the key difference between allopatric and sympatric speciation?

A

Allopatric speciation involves geographic separation, while sympatric does not.

B

Allopatric speciation involves two populations while sympatric involves more than two.

C

Sympatric speciation cannot result in the formation of two new species.

D

Allopatric speciation cannot occur within one location, while sympatric can.

A

Which of the following populations is not in hardy weinberg equilibrium?

a a population with 12 homozygous recessive individuals (yy), 8 homozygous dominant individuals (YY), and 4 heterozygous individuals (Yy) 

b a population in which the allele frequencies do not change over time 

c p^2 + 2pq + q^2 = 1 

d a population undergoing natural selection

d

Which of the following microevolutionary forces is not likely to disrupt a population that is in genetic equilibrium? 

a Small population size 

b Mutation 

c Random mating 

d Gene flow

c

If we want to know the percentage of particular genotypes within an actual population assuming complete dominance and two alles the one measurement we have to actually make is of the frequency of the 

a heterozygous phenotype. 

b recessive phenotypes. 

c heterozygous genotypes. 

d homozygous dominant genotypes. 

e dominant phenotypes.

b

In a colony of 100 vampire bats 16 show the recessive traits of bristly hair. What is the percentage of heterozygotes in the population

A 36 percent

B 24 percent

C 52 percent

D 48 percent

E 84 percent

d

If individuals move from one population to another it may cause a shift in allele frequencies due to 

a genetic drift 

b directional selection

c natural selection 

d mutation

e gene flow

e

natural selection results in 

a genetic drift. 

b a new species. 

c stabilizing selection. 

d a mutation. 

e adaptation

e

which situation is most likely an example of convergent evolution 

a Squid and humans have eyes similar in structure. 

b Worms and snakes both move without legs. 

c Some bats and birds have wings that allow them to fly 

d all of the above

d

which of the following best describes the conditions in which sympatric speciation occurs 

a It occurs when individuals are separated by geographical barriers 

b It occurs in populations that border one another. 

c It occurs when individuals living together become reproductively isolated. 

d None of these

c

which of the following best describes the process necessary for allopatric speciation 

A Random mating and gene flow between populations 

B Geographical barriers leading to reproductive isolation 

C Increased gene flow and reduction in genetic variation 

D Constant environment with no selection pressure

B

Stabilizing selection increases genetic and phenotypic variation and decreases the frequency of intermediate phenotypes

a

True

b

False

b

According to the Hardy Weinberg principle, microevolution occurs when ______________.

a

a population is closed to migration from other populations

b

when a population has different forms of the same gene

c

a population experiences a shift in allele frequencies

d

no mutations are occurring in a population

e

a feature of an individual animal changes through use or disuse

c

In an isolated population of elephants, 16 percent of the individuals have large ears, a homozygous recessive condition, and 84 percent have the dominant small ears phenotype. What percentage of the population are heterozygotes?

a

88%

b

32%

c

4%

d

48%

e

16%

d

The agent of microevolutionary change that is most likely to introduce genetic variation from another population is referred to as ______________.

a

natural selection

b

genetic drift

c

nonrandom mating

d

mutation

e

gene flow

e

If there are two alleles for a gene in a population, and the frequency of the dominant allele (p) is .6, then the frequency of the recessive allele (q) is

a

0.4

b

0.6

c

0.48

d

0.25

e

0.025

a

The organism with the highest fitness is

a

An animal that lives 10 years and produces 10 offspring per year.

b

An animal that lives one year and produces 10 offspring total.

c

An animal that lives 100 years and produces 10 offspring total.

d

An animal that lives 2 years and produces 10 offspring per year.

e

An animal that lives 10 years and produces 2 offspring per year.

a

Natural selection acts upon the __________ to create microevolutionary change.

a

genotypic frequencies of a population

b

alleles of an individual organism

c

allele frequencies in a population

d

phenotype of an individual organism

e

alleles in the gene pool of a population

d

Natural selection results in ______________.

a

adaptation

b

gene flow

c

new species

d

genetic drift

e

mutations

a

Changing environmental conditions would most likely cause an existing species to undergo ______________.

a

directional selection

b

disruptive selection

c

lethal mutation

d

deleterious mutation

e

stabilizing selection

a

Natural selection exerts little or no effect on traits that appear during an individual’s ______________.

a

reproductive life

b

embryonic development

c

juvenile phase

d

post-reproductive life

e

preadolescent years

d

Genetic drift will have a progressively larger impact on allele frequencies in a population as ______________.

a

gene flow increases

b

population size decreases

c

population size increases

d

mutation rate decreases

e

random mating increases

b

Knowing that each diploid organism has one copy of each gene, a scientist can calculate the relative abundances of the different alleles in a population.

a

True

b

False

b

The accumulation of traits that increase the relative fitness of organisms in their environment over time results in ______________.

a

homozygote advantage

b

heterozygote advantage

c

adaptation

d

mutation

e

diploidy

c

Which of the following evolution-related events are in the correct cause-and-effect sequence?

a

natural selection →variation →mutation →adaptation →speciation

b

mutation →speciation →adaptation →variation →natural selection

c

variation →adaptation →mutation →natural selection →speciation

d

speciation →adaptation →variation →mutation →natural selection

e

mutation →variation →natural selection →adaptation →speciation

e

The wings of a bird and the wings of a bat show morphological ______ and are ______.

a

homologous, convergence

b

homologous, divergence

c

convergence, analogues 

d

analogues, divergence

c

Two closely related species of mice might mate and produce a fertilized egg, which is subsequently aborted. This is an example of:

a

temporal isolation.

b

hybrid inviability.

c

hybrid vigor.

d

hybrid breakdown

b

Which of the following best describes the conditions in which sympatric speciation occurs?

a

It occurs when individuals are separated by geographical barriers

b

It occurs in populations that border one another.

c

It occurs when individuals living together become reproductively isolated.

d

None of these

c

A population of elephants that has been hunted to near extinction but is then allowed to recover most likely experienced:

a

natural selection.

b

genetic divergence

c

a population bottleneck

d

the founder effect.

c

Which of the following microevolutionary forces is NOT likely to disrupt a population that is in genetic equilibrium?

a

Small population size

b

Mutation

c

Random mating

d

Gene flow

c

A paleontologist estimates that when a particular rock formed, it contained 32 mg of the radioactive isotope potassium-40, which has a half-life of 1.25 billion years. The rock now contains 2 mg of the isotope. About how old is the rock?

a

2.5 billion years

b

5.0 billion years

c

0.3 billion years

d

0.4 billion years

e

1.25 billion years

b

The biological species concept emphasizes the ability of individuals to ______________.

a

intermingle with other species

b

interbreed and produce fertile offspring

c

live in a variety of habitats

d

have greater longevity

e

adapt to the environment

b

Female fireflies identify males by their flashing patterns, which are often so complicated that signals sent by one species cannot be understood by another species. This reproductive isolating mechanism is called __________.

a

behavioral isolation

b

mechanical isolation

c

gametic isolation

d

temporal isolation

e

ecological isolation

a

Which combination is an example of prezygotic mechanisms of isolation?

a

mechanical and temporal isolation

b

mechanical and hybrid breakdown

c

hybrid breakdown and temporal isolation

d

hybrid breakdown and gametic isolation

e

hybrid sterility and temporal isolation

a

Speciation that takes place when a physical barrier subdivides a large population is called ______________ speciation.

a

geographic

b

sympatric

c

parapatric

d

morphologic

e

allopatric

e

Allopatric speciation typically occurs in two stages. The first stage is ______________ of two populations and the second stage is ______________.

a

genetic drift; reproductive isolation

b

reproductive isolation; geographic separation

c

natural selection; geographic separation

d

geographic separation; reproductive isolation

e

mutation; reproductive isolation

d

A small population isolated at the edge of a species’ geographic distribution may experience ______________ and genetic drift, which may lead to the evolution of distinctive traits by ______________ .

a

population bottlenecks; artificial selection

b

natural selection; population bottlenecks

c

a founder effect; natural selection

d

gene flow; natural selection

e

population bottlenecks; founder effects

c

Abrupt genetic changes that quickly lead to the reproductive isolation of a group of individuals will likely lead to ______________.

a

sympatric speciation

b

secondary contact

c

geographic separation

d

species fusion

e

allopatric speciation

a

On the Hawaiian Islands, speciation in Drosophila occurred when a small group of males and females colonized a new island, where they faced environmental selection pressures. In addition, sexual dimorphism – and therefore, sexual selection – maintained reproductive isolation from other populations on the new island. These populations, although closely related, remained ecologically different. These events are examples of ______________.

a

a founder effect and genetic drift, but not adaptive radiation

b

a founder effect only

c

adaptive radiation only

d

a founder effect, genetic drift, and adaptive radiation

e

genetic drift only

d