Exam 12: Mechanisms of Evolution

Sexual selection can result in an increased frequency of alleles,which

Gene flow between two populations

Which of the following is NOT likely to be a cause of rapid evolution in a population?

Insecticides are used to kill insects.However,insecticide-resistant insects are being found.What is the mechanism for this new insect trait?

Jean-Baptiste Lamark proposed that populations evolve when traits acquired during the lifetime of a parent are passed down to offspring.What is wrong with this proposal?

In natural selection,________ that increase survival and reproductive success become more common in a population.

The population of a cactus species in a particular area has two to seven spines with an average of four spines per square centimeter of surface area.Cacti with fewer than four spines per square centimeter are more easily eaten by the wild boars thriving in the area.Over time,the population of this cactus species in this area have an average of six spines per square centimeter of surface area.This is an example of

When individuals with intermediate phenotypes have an advantage over all others in the population,such as the case with human birth weight in the 1930s-1940s,________ selection is the likely mechanism of evolution responsible.

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.

When robins lay a clutch of more than four eggs,their chicks are often malnourished because they have so many to feed.If the robins lay fewer than four eggs,they may not have any viable offspring.As a result,robins typically lay a clutch of four eggs.This is an example of

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

Genetic variation is based on

Evolution occurs when there are changes in the frequencies of alleles and genotypes in a(n)________ over time.

The only mechanism of evolutionary change that is not influenced by chance events is ________.

Match each example to one of the processes below. -A large boulder rolls down a mountain and kills all the flowers in its path.

Some finches on the Galápagos Islands eat insects,an unusual food for finches to eat.These finches

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

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.

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.

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