1. Connecting Modern Organisms to Ancient Organisms
7.5.3

2. This animal is a Paraceratherium that became extinct over 23 million years ago. It stood over 16 feet tall and was over 4 feet long. How does this animal remind you of animals that lived on the Earth today?

3. Scientists use the fossil record to construct ideas about organisms that have gone extinct. Fossil records show patterns in the traits of ancient organisms that are similar to organisms on Earth today.

4. Common Descent: when different species evolve from a common ancestor.
Modern Crocodile Skull
Ancient Megalania Skull
Scientists use the size, shape and type of teeth in a skull to determine how two animals are related. The megalania is an ancestor of the crocodile. What evidence do you see from the skulls that supports this claim?

5. Are they related?
Modern Asian Elephant
Fossil of Uintatherium

6. Are they related?
What evidence can you find that the modern wales are descendants to the Uintatherium?
Modern Whale
Fossil of Uintatherium

7. Now that we have examined evidence that both the modern elephant and the whale have a common ancestor, the Uintatherium, what does this tell us about the relationship of elephants and whales today?

8. What is this?

9. Why do you have a tail bone (coccyx) if you don’t have a tail?
Your ancient ancestors did have a tail! These structures that are still present in the modern skeleton of humans is evidence that supports the theory of evolution.

10. Vestigial Structures
“left-over” structures found in skeletons that don’t have a use now. These structures support the theory of evolution and how species have changed over time.

11. Ostrich Wings, another vestigial structure, are too small to allow an ostrich to fly.
Over many generations, the ostrich’s wing size has changed.