Exam 12: Mechanisms of Evolution

Several related bird species live in a desert.One species is much smaller than the other species.This small species nests in holes in cacti.Because the bird is so small,it can easily squeeze between the spines of the cactus and create a well-protected nest.This is an example of

New-world vultures are related to raptors,while old-world vultures are more closely related to storks.However,both of these birds eat carrion (decaying animals)and have a similar beak structure.Explain how this similarity in beak structures arose.

What is genetic drift?

A chance evolutionary change occurring in small populations is referred to as ________.

Evaluate the accuracy of the following statement: "The natural selection of a prey species can be altered if a new predator is introduced." Explain how you reached your conclusion.

Compare and contrast bottleneck and founder effect.

Two populations of geese live near each other.As time passes,the populations are becoming more genetically alike.This is probably due to ________.

Convergent evolution produces

Gene flow occurs

Natural selection acts on ________ traits.By favoring certain phenotypes over others,the individuals having those phenotypes survive and reproduce at a higher rate than individuals who do not have those traits.

The original source of genetic variation within a population is ________.

A scientist is studying beak length in a species of hummingbird.The scientist establishes a population of birds with beaks ranging from very small to very long and allows the population to breed for 10 years.At the end of the experiment,she finds that the majority of birds in the population have very long beaks.This is an example of the ________ selection pattern of natural selection.

Between 1980 and 1999,the Food and Drug Administration (FDA)approved 52 new antibacterial drugs.Only 8 new antibacterial drugs gained approval between 2000 and 2012.The lack of new antibacterial drugs may contribute to the ________ selection of antibiotic-resistant bacteria.

The result of convergent evolution is ________ traits.

A friend states,"Exposing bacteria to antibiotics causes the cells to mutate to become antibiotic resistant." Explain to your friend why he is incorrect and provide the correct explanation.

The color of a certain species of beetle is determined by a single gene.Two beetles homozygous for green coloration (meaning they have two copies of the green allele)produce a single offspring with brown coloration.Brown color appeared in this offspring as a result of

In an original population of 30 mice,the frequency of dark-fur-pigment alleles is 57% and the frequency of white-fur-pigment alleles is 43%.Ten generations later,the population of 30 mice now has 28 dark-fur-pigment alleles and 32 white-fur-pigment alleles? What are the new allele frequencies? Is there evidence of ongoing evolution? Explain.

Genetic variation is based on

A fisherman catches one trout from each of two ponds.Pond A contains 100 trout and pond B contains 1,000 trout.Which population is more affected by the fisherman?

Bees and hummingbirds are very good accidental pollinators.When they visit flowers to extract nectar,they pick up pollen from a flower and carry it to the next flower that they visit; this helps to distribute the pollen and the genes carried in the pollen to a different plant.Explain how bright red wildflowers that easily attract bees and hummingbirds might become more prevalent in a wildflower population of both red and white flowers through natural selection.