Evolution Test

Evolutionary changes occur when ________ acts upon populations containing individuals with genetic differences.

An example of evolution that has been readily observed is

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

An insect with a random mutation is not killed by the insecticide and reproduces.

Why might many new species form in the aftermath of a mass extinction?

Changed environments and reduced competition would provide opportunities for new adaptations.

Which of the following statements about evolution is true?

Evolution can result in the addition or loss of traits in existing organisms.

Cultivation of corn over thousands of years has resulted in a modern corncob that looks very different from the tiny ancestral cob. Does this support the concept of evolution?

Yes; artificial selection demonstrates that evolution can occur, even though the driving force was humans rather than natural selection.

Evolution can be described as

a change in the genetic characteristics of a population of organisms over time.

The emergence of each new branch on the evolutionary tree represents

a common ancestor and the introduction of a new shared derived feature.

The most recent mass extinction, which occurred during the Cretaceous period, may have been caused by

an asteroid hitting Earth.

The hands of a human and the hands of a chimpanzee are similar in structure because humans

and chimpanzees share a recent common ancestor.

Disruptive selection operates whenever

both extremes of the phenotype are more successful.

Speciation

can result from geographic isolation.

In many predator-prey relationships, evolutionary change in the prey will result in evolutionary change in the predator, a phenomenon known as

coevolution

The fossil record

contains strong evidence that major new groups of organisms arose from previously existing organisms.

Two different species may have similar features because of

descent from a common ancestor.

Which of the following is NOT a mode of natural selection?

dormant selection

Both insects and humans evolved jointed legs to allow locomotion on land. These structures are considered analogous because insects and humans

evolved from different ancestors.

For the species Homo sapiens the first part of the name, Homo, denotes the

genus

Both humans and whales evolved from a common ancestor. Although our forelimbs are quite different, they are made of the same bones. This is an example of a(n)

homologous structure.

Tails are found

in embryos of a wide variety of organisms, some of which have a tail as adults and others do not.

An example of evolution that has been readily observed is

increased resistance of bacteria to an antibiotic that is used to kill them.

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

may be harmful to the individual's survival but is always beneficial to its reproductive rate.

The proteins and DNA of organisms that share a recent common ancestor are ________ the proteins and DNA of organisms that do not share a recent common ancestor.

more similar than

New alleles arise by

mutation

The result of ________ over evolutionary time spans is that alleles that allow organisms to survive and reproduce at a higher rate than other individuals become more common in the population.

natural selection

Fossils found in deeper layers are ________ than fossils found in more shallow layers.

older

In general, geographical isolation occurs when

populations are separated by a distance that is great enough to limit gene flow.

Which of the following is NOT a cause of evolution?

stable environmental conditions

A species of cave beetle that lives in total darkness is blind but has remnants of what looks like eyes. These "eyes" are

vestigial

Gene flow occurs

when an individual migrates between two otherwise isolated populations of a species.