Common Ancestry (2)

Common descent refers to the formation of new species from an ______________ population.

Homologous Structures help us to understand that

• Many species are no longer alive.

• Some species share a common ancestor

• All organisms share similar bones.

Biogeography is the study of how and why animals _________ where they do.

The data in the diagram is evidence that —

• a new species of horse suddenly appeared

• horses slowly developed over time

• horses have similar stages of rapid embryological development

• horses have a common ancestry with other hooved animals

These limbs provide evidence of common ancestry because they —

• have the same basic structure

• perform the same function

• are the same size

• are parts of mammals

The fact that both these mammals incubate their immature offspring in a pouch provides evidence that they —

• belong to the same species

• must range great distances to eat

• have very similar skeletal structures

• are descended from a common ancestor

In 2010, scientists excavated a skull fossil that provides evidence of a newly discovered species of big cat. Based on the evidence, scientists hypothesize that big cats branched off from smaller wild cats about 6 million years ago. Which of these resources did the scientists most likely rely on to form their hypothesis?

• A food web showing feeding relationships of organisms where the fossil skull was found

• Population and migration data for small wild cats living in the ecosystem where the skull was found

• The fossil record and DNA comparisons of big cats and small cats

• The historical record of interactions between different species of big cats

Which statement is best supported by the observable structures of the different humerus

• The primates lived in similar environments.

• The primates shared a common ancestor.

• The primates interbreed with similar organisms in a population.

• The primates had diets that consisted of similar types of foods.

Which statement is supported by this cladogram?

• Hippopotamuses are more closely related to cows than to javelinas.

• Toothed whales are more closely related to mouse deer than to hippopotamuses.

• Javelinas and pigs are more closely related than baleen whales and toothed whales.

• Cows and mouse deer are more closely related than javelinas and pigs.

Pangaea was once a supercontinent. As these land masses split organisms of many species also separated. This means that today we find close ___________ of many species on different continents.