AP Biology Quiz (Chapter 22, 23, 24, 25)

Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island? (Hint: How do colonization events trigger speciation?)

- The separation of habitats reduced gene flow between the populations - Natural selection favored individuals that were more fit in the new environment - Genetic drift occurred in the two populations WHY? Physical isolation, natural selection, and genetic drift are all events that lead to speciation.

Which of the following are causes of evolutionary change?

-Gene Flow -Mutation -Genetic Drift -Natural Selection

What is genetic drift? (Hint: What causes genetic variation in populations over time?)

A change in allele frequencies caused by random events WHY? Genetic drift is a random change in allele frequencies over time.

True or False? A mating between a tetraploid individual and a diploid individual produces biologically fit offspring. (Hint: What gametes are formed from the offspring of this mating?)

False WHY? Offspring produced from this mating would be triploid and likely produce nonviable gametes with an uneven number of chromosomes.

True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats. (Hint: What effect did the ice age have on existing habitats?)

False WHY? The last ice age produced many different species mainly because of vicariance events; the glaciers physically separated populations from each other.

The wing of a bat is homologous to the ______ of a whale.

Flipper WHY? The bones of a bat wing and a whale flipper are homologous.

What prevents speciation from occurring in sympatric populations? (Hint: Which factor prevents genetic isolation in sympatric populations?)

Gene flow WHY? Gene flow prevents speciation in sympatric populations.

How many chromosomes would be found in an allopolyploid plant if its parents had diploid numbers of 2 and 10, respectively? (Hint: The parental gametes are haploid.)

Haploid number of 6 WHY? The parents contribute one and five chromosomes, respectively, to their gametes, and the zygote is a haploid plant because the chromosomes do not exist in homologous pairs.

Generation-to-generation change in the allele frequencies in a population is _____.

Microevolution WHY? Generation-to-generation change in the allele frequencies in a population is the definition of microevolution.

In 1959, doctors began using the powerful antibiotic methicillin to treat infections of Staphylococcus aureus, but within two years, methicillin-resistant strains of S. aureus (MRSA) appeared. How did the resistant strains of S. aureus emerge?

Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common. WHY? Evolutionary change comes about as the proportion of individuals in the population displaying a particular trait increases from generation to generation.

Which of the following statements about reinforcement is true? (Hint: Consider how reinforcement promotes the divergence of species.)

Reinforcement is a type of natural selection. WHY? Reinforcement is a type of natural selection called disruptive selection, which favors extreme phenotypes over intermediate phenotypes.

Which term is used to describe populations that live close enough to interbreed? (Hint: Which term means "same homeland"?)

Sympatry WHY? Sympatry describes populations that live close enough to interbreed.

What would be the ploidy of the viable gametes produced by a tetraploid individual if nondisjunction of all chromosomes occurred in meiosis I? (Hint: Consider what happens to chromosomes if nondisjunction occurs during meiosis.)

Tetraploid WHY? Tetraploid gametes would be produced if all chromosomes migrated to one pole during meiosis I.

Which of the following is(are) homologous to the bones in this image? (Bones of the flipper of the whale)

The cat paw WHY? The digits of a cat are homologous to those of these whale bones.

What is the meaning of Darwin's expression "descent with modification"?

Descent with modification refers to evolutionary change over time. WHY? Darwin used this term to describe change in organisms over time, or evolutionary change.

A population of birds colonizes an area in which the insects upon which they feed live inside trees. Which of the following events accounts for an observed increase in average beak size in the bird population over time? (Hint: Consider how the birds have adapted to their new environment.)

Increased fitness of large-beaked birds, leading to natural selection. WHY? Birds with larger beaks are better able to survive in the new environment.

How can an allopolyploid plant become a biologically fit new species? (Hint: Consider how an allopolyploid plant can be made fit to reproduce.)

Nondisjunction event during mitosis WHY? If a nondisjunction event occurred that resulted in chromosome doubling, the plant's ability to undergo meiosis would be restored and it could then produce viable gametes.

A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to its original habitat. Which of the following statements about these bird populations is true? (Hint: Think about how the birds were separated and what happens when speciation does or does not happen.)

The populations will not be able to interbreed because they are different species. WHY? Different species cannot interbreed.

Which of the following statements about autopolyploid individuals is true? (Hint: Think about what distinguishes autopolyploidy from allopolyploidy.)

They contain more than two haploid sets of chromosomes. WHY? All polyploid individuals contain more than two haploid sets of chromosomes.

True or false? A flood that separates a population of frogs onto opposite sides of a lake is an example of a vicariance event that may result in allopatric speciation. (Hint: Think about how allopatric speciation can occur.)

True WHY? Allopatric speciation may occur when populations are separated geographically; this type of speciation can begin with a vicariance event, in which a geographic barrier such as water isolates a population, or a dispersal event, in which a subsetof a population migrates to a different habitat.