Geologic Time and Evolution

What has the study of fossils allowed scientists to do?

• describe past environments and the history of life

• study present ocean temperatures at different depths

• analyze the chemical composition of sedimentary rocks and minerals

• predict which organisms will become extinct in the future

During the Cambrian Explosion that began the Paleozoic Era, the many new forms of life that evolved

• lived on land.

• were invertebrates that lived in the sea.

• were vertebrates covered with scales or fur.

• were single-celled.

Earth’s earliest atmosphere lacked which gas that is necessary for life as we know it to exist today?

• nitrogen

• carbon dioxide

• argon

• oxygen

A species is a group of similar organisms that

• can mate with each other and produce fertile offspring.

• can live together on an island.

• can migrate to an island from the mainland.

• all have exactly the same traits.

Which of these is one of the main ways that a new species forms?

• Cross-breeding occurs within the species.

• A group is separated from the rest of the species.

• Competition occurs between members of the species.

• Mutations occur in the alleles of members of the species.

Which term refers to similar structures that related species have inherited from a common ancestor?

• DNA sequences

• developmental organisms

• homologous structures

• punctuated equilibria

A trait that helps an organism survive and reproduce is called a(n)

• mutation.

• selection.

• adaptation.

• variation.

Which term refers to the process by which individuals that are better adapted to their environment are more likely to survive and reproduce?

• natural selection

• overproduction

• competition

• variation

Darwin concluded that organisms on the Galápagos Islands

• had changed over time.

• had remained the same.

• were the result of selective breeding.

• had no variations.

Which term refers to a species creating more offspring than can possibly survive?

• natural selection

• overproduction

• evolution

• variation