Pre-Test on Common Ancestry

The bones in the wings of a bat are the same as the bones found in the paws of raccoon, though their function is quite different. The similarity is evidence that the bat and the raccoon–

• hunt for the same prey.

• live in similar habitats.

• share a common ancestor.

• are about the same size.

The fossil record of birds is said to be incomplete. What is a possible reason for an incomplete fossil record?

• Birds were eaten by other animals.

• Fossils are used to study extinct animals, and birds are not yet extinct.

• Dinosaur fossils are more interesting for scientists to study.

• Bird bones are light and hollow and therefore unlikely to fossilize.

Periods of stasis, during which organisms do not change in the fossil record, can be accounted for in modern evolutionary theory by understanding that –

• the adaptation of plants and animals have not changed very much in the fossil record.

• the fossil record has gaps caused by slower than usual rates of sedimentation.

• a constant climate gives an advantage to species that stay in one place.

• some organisms live for long periods in a habitat with no selective pressure.

Which of the following provides evidence of a common ancestor?

• Insects and birds both have wings.

• Whales and wolves share a similar anatomy.

• Dogs and kangaroos both care for their young.

• Mosquito larvae and shrimp both live in water.

Studying which of the following would provide the best evidence that two organisms share a common ancestor?

• Amino acid sequence

• Habitat

• Dietary requirements

• Social group interactions