Theory of Evolution (Extra Practice)

Which of the following is a result of cheetahs having gone through a population bottleneck?

• The cheetah species is more likely to become extinct.

• Mutations occur more frequently in the cheetah genome.

• Individual cheetahs have different alleles for many genes.

• The cheetah population cannot increase past a certain size.

Which is one way that natural selection differs from genetic drift?

• Natural selection causes the frequencies of alleles in a population to change.

• Natural selection affects smaller populations more often than larger populations.

• Natural selection results from some individuals producing more offspring than others.

• Natural selection depends on some traits helping individuals survive in their environment.

A particular gene has two alleles, G and g. Each allele has a frequency of 50% in a population. Which is most likely to preserve these allele frequencies?

• The population doubles in size over several generations.

• A number of individuals with one allele migrate from the population.

• One allele results in a phenotype that better enables organisms to reproduce.

• A population bottleneck temporarily reduces the population size by one-tenth.

Recently, bears have been found in the Arctic Circle that are hybrids between grizzly bears and polar bears. Which type of isolating mechanism usually keeps these species from producing offspring?

• mating and breeding in different habitats

• production of a nonviable embryo or fetus

• inability of sperm to reach the egg during mating

• failure of the fertilized egg to implant in the uterus

Under which of the following conditions would a dominant allele that coded for a fatal disease most likely remain in a population?

• The allele is acted on by natural selection.

• The gene is expressed only in members of one sex.

• The gene is expressed in individuals late in their lives.

• The allele mutates to a nonfatal form during an individual's lifetime.

Imagine that DNA replication and cell division were completely error-free and that cell DNA were completely protected from substances that cause mutation. How would natural selection be affected?

• It would become more efficient, since it removes mutations from the populations.

• It would become ineffective, since it depends on variations within populations.

• It would become unnecessary, since organisms would be better adapted to their environments.

• It would become more obvious, since it would improve on organisms with better cell processes.

Which statement best describes the significance of Archaeopteryx fossils?

• They revealed the direct ancestor of birds.

• They prove that dinosaurs were feathered.

• They provided the first evidence for evolution.

• They show that birds and dinosaurs have a common ancestor.

Which of the following structures are not homologous?

• the wings of a fly and the wings of a pigeon

• the gills of a goldfish and the gills of a shark

• the arms of a human and the arms of a chimpanzee

• the roots of a white oak tree and the roots of a red oak tree

Which statement best describes the baleen whale structure that is indicated by the arrow?

• It is a transitional form connecting different types of whales.

• It is analogous to the pelvis and legs of mammals that walk on land.

• It is vestigial structure that indicates the whale's evolutionary history.

• It is homologous to organs with reduced function, such as the human appendix.

Which pair of structures is homologous but not analogous?

• bird wing and bat wing

• bat wing and moth wing

• moth wing and dolphin flipper

• dolphin flipper and bird wing