Morphed -- When Whales Had Legs -- National Geographic Cetacean Evolution

1. What helped Phillip Gingerich decide what kind of fossil he had found?

Gingerich discovered a Sygmoid Process, a part of the structure of the inner ear, that is unique to whales.

2. Why does Pakicetus go into the water in the first place?

The climate changed to arid conditions, and as the planet warmed, marine life flourished, while many of the common prey items of Pakicetus on land went away.

3. What was the problem in the water for Pakicetus?

One of the main problems facing Pakicetus was predation. Pakicetus was still far away from being an efficient, streamlined swimmer like modern whales. It most likely had to paddle like a dog, making it an easy target for Crocodilians.

4. According to Hans Thewissen, how has Pakicetus adapted to life in the water?

Tail develops muscles and flattens like that of an otter. Back legs shorten and widen to act like flippers. The body becomes more streamlined.

5. Thewissen named the new species Ambulocetus natans, which means-------?

Ambulocetus natans means "The walking and swimming whale."

6. How do they know if it lived in the sea full time?

In order to tell wether Ambulocetus lived permanantly in the oceans, you have to determine if it could have drunk seawater. A land animal wouldn't be able to handle the extra salt, while a marine animal could.

7. It really drank...?

Ambulocetus natans drank freshwater.

8. Ambulocetus vanishes from the -------------- 49 million years ago

49 million years ago, Ambulocetus vanishes from the fossil record.

9. How has the new species adapted to living in water?

A shorter, more powerful neck for better diving; rear legs widen and become more flipper-like; tail develops muscles.

10. The key to Rotocetus success in the ocean is linked to its organ of balance in the inner ear. It is much smaller in whales, allowing it to be acrobatic and agile enough to avoid predators.

11. Basliosaurus lived in the shallow Tethys sea 39 million years ago. What does Basilosaurus mean?

Basilosaurus means "King lizard." (When first described, scientists thought it was a Mosasaur.)

12. What adaptations does Basilosaurus have?

Exceptional eyesight; Improved underwater hearing; long thin body shape to hunt in shallow water.

13. Even though Durodon is much smaller than Basilosaurus, what may have helped it survive?

It is believed that Durodon might have travelled in pods.

14. 36 million years ago, ----------------- died out. why?

Basilosaurus died out 36 million years ago. The climate was cooling, causing sea levels to drop. Basilosaurus was adapted to hunting in shallow waters, and due to the loss of its habitat, it had to try and dive, which it was not designed to do.

15. ------------------- is the whale that gives rise to modern whales.

Durodon survived to become the lineage that would give rise to today's whales.

16. 30 million years ago Megalodon ate Durodons. What did Durodons do that helped them survive?

Durodon migrated northwards over time, to escape Megalodon.

17. How have modern whales adapted to deep diving?

Modern whales can control the flow of blood to their hearts and brains.

18. Today, there are more than 80 whale species.

19. The Grey Whale can swim more than 12,000 miles in an annual migration.

20. Orcas can reach speeds of 34 miles per hour.

21. Bowhead whales can live for over 200 years.