Evidence for Evolution

Question 1

Scientists compare the forelimb bones of a bat, a human, and a fossilized reptile that lived 250 million years ago. Each has a humerus, radius, ulna, wrist bones, and digits, although the shapes differ. Which explanation best accounts for these similarities and differences?

Accepted Answer

All three species share a common ancestor that had a similar forelimb structure; the differences are due to later adaptations.

Answer

The differences in bone shape show that the three species are not related at all.

Answer

The fossil reptile is a direct ancestor of the bat, so the bat inherited its forelimb directly from that fossil species.

Answer

The bat and human developed similar forelimb bones independently because they both need to fly.

Question 2

Paleontologists compare the forelimb bones of a fossil woolly mammoth (Mammuthus primigenius) with those of a modern African elephant. They note that both have a similar arrangement of the humerus, radius, and ulna, and both have large tusks, but the mammoth’s tusks are curved and its bones are slightly shorter. Which explanation best accounts for these anatomical similarities and differences?

Accepted Answer

The mammoth and the modern elephant share a recent common ancestor; over time, evolutionary changes produced the observed differences while many bone structures remained similar.

Answer

The differences in tusk shape and bone length are due solely to random genetic mutations that have no connection to evolutionary history.

Answer

The modern elephant is a direct, unchanged descendant of the woolly mammoth, so any differences are only due to preservation artifacts.

Answer

The mammoth and the modern elephant evolved the similar bone arrangement independently because they lived in cold environments, a case of convergent evolution.

Question 3

Which of the following is a line of empirical evidence that scientists use to support the idea of common ancestry?

Accepted Answer

Similar DNA sequences found in the genomes of different species.

Answer

Fossils that show a species unchanged for millions of years.

Answer

Similarities in the way unrelated species use tools to obtain food.

Answer

The belief that each species was created in its present form by a deity.

Try three questions

Scientists compare the forelimb bones of a bat, a human, and a fossilized reptile that lived 250 million years ago. Each has a humerus, radius, ulna, wrist bones, and digits, although the shapes differ. Which explanation best accounts for these similarities and differences?

Which of the following is a line of empirical evidence that scientists use to support the idea of common ancestry?

Keep going on this shelf