Question

test corrections change over time csa
chp 13.3

which of the following can be determined using the figure above? (mark all that apply)

□ the hipparion and the megahippus have a common ancestor.
□ the hyracotherium is a common ancestor of many other horse - like species.
□ the anchitherium evolved from the callippus.
□ horse - like organisms did not exist before 5 million years ago

Explanation:

1. For "The Hipparion and the Megahippus have a common ancestor": By looking at the evolutionary tree, Hipparion and Megahippus share a common branch (trace back their lineages), so this is correct.
2. For "The Hyracotherium is a common ancestor of many other horse - like species": Hyracotherium is at the bottom (earliest time) of the tree, and many other horse - like species branch out from lineages that can be traced back to it, so this is correct.
3. For "The Anchitherium evolved from the Callippus": In the tree, Anchitherium is from an earlier time (23 - 5 mya range) and Callippus is in a different branch. The direction of evolution is from earlier to later, so Anchitherium could not have evolved from Callippus, this is incorrect.
4. For "Horse - like organisms did not exist before 5 million years ago": The tree shows species (like Hyracotherium) existing at 55 - 34 mya, which is before 5 mya, so this is incorrect.

Answer:

• The Hipparion and the Megahippus have a common ancestor.
• The Hyracotherium is a common ancestor of many other horse - like species.