Cow to Whale Transition
If a teacher is making a claim that land animals evolved into whales, students should ask:
What precisely is involved? How does the fur turn into blubber, how do the nostrils move, how does the tiny tail turn into a great big fluke?'
Cetaceans have many unique features to enable them to live in water. For example:
- Enormous lung capacity with efficient oxygen exchange for long dives.
- A powerful tail with large horizontal flukes enabling very strong swimming.
- Eyes designed to see properly in water with its far higher refractive index, and withstand high pressure.
- Ears designed differently from those of land mammals that pick up airborne sound waves and with the eardrum protected from high pressure.
- Skin lacking hair and sweat glands but incorporating fibrous, fatty blubber.
- Whale fins and tongues have counter-current heat exchangers to minimize heat loss.
- Nostrils on the top of the head (blowholes).
- Specially fitting mouth and nipples so the baby can be breast-fed underwater.
- Baleen whales have sheets of baleen (whalebone) that hang from the roof of the mouth and filter plankton for food.
Many cetaceans find objects by echo-location. They have a sonar system which is so precise that it's the envy of the U.S. Navy. It can detect a fish the size of a golf ball 230 feet (70 m) away. It took an expert in chaos theory to show that the dolphin's ‘click’ pattern is mathematically designed to give the best information.
One amazing adaptation of most echo-locating dolphins and small whales is the ‘melon,’ a fatty protrusion on the forehead. This ‘melon’ is actually a sound lens—a sophisticated structure designed to focus the emitted sound waves into a beam which the dolphin can direct where it likes. This sound lens depends on the fact that different lipids (fatty compounds) bend the ultrasonic sound waves traveling through them in different ways. The different lipids have to be arranged in the right shape and sequence in order to focus the returning sound echoes. Each separate lipid is unique and different from normal blubber lipids, and is made by a complicated chemical process, requiring a number of different enzymes.
For such an organ to have evolved, random mutations must have formed the right enzymes to make the right lipids, and other mutations must have caused the lipids to be deposited in the right place and shape. A gradual step-by-step evolution of the organ is not feasible, because until the lipids were fully formed and at least partly in the right place and shape, they would have been of no use. Therefore, natural selection would not have favored incomplete intermediate forms.
Two Semi-Technical Papers
A Whale Fantasy from National Geographic
