For Natural Science Guru labs

LAB REPORT LAB 08: EVOLUTION OF THE HORSE

THIS SHOULD BE COMPLETED AND INCLUDED IN YOUR LAB NOTEBOOK.

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1. Connect the points representing the genera Hyracotherium, Orohippus, Epihippus, Mesohippus, and Miohippus.

What seems to be the trend in cheek size during this time?

Is it possible to connect the points on the time line further to the right with a single line?

2. Without drawing such a line, describe the trend of evolution during the Miocene, Pliocene, and Pleistocene.

3. Now you connect the data points. Use the family tree on the Lab 8 Exercise to create the lines between the points on your graph. (it might be helpful if you print out the tree and label the names with the corresponding numbers assigned on the table and graph) ***if the family tree is too small, you can find it @ www.doctortree.com

4. What was the average change in the span of cheek teeth per million years from Hyracotherium to Miohippus?

5. From Miohippus to Equus?

6. From this graph and your results what generalization can you make about the rate of evolutionary change within the Equidae?

7. What evidence do you have that the direction of an evolutionary change can be reversed?

8. If a line ends as in the Archaeohippus, what does that mean to that genetic line?

Time/Epoch

Span of cheek teeth (cm)