Whale
by Renee R.
My animal is the whale. The whale is a member of the cetacean group, which includes whales, dolphins, and their relatives. They have fins and live underwater, but breathe air. They have blow holes to blow out all of the water. They can grow to be between 25 and 80ft. long, depending on the type of whale. There are seventy-eight known species of whale. They are then broken up into two groups, baleen and toothed whales. There are eleven baleen whales and sixty-seven toothed whales. Toothed whales, obviously, have teeth. Baleen whales have baleen, which are instead of teeth; they filter out things that the whale should not eat.
Whales are ungulates, which means they evolved to have hooves, but whales became cetaceans and eventually evolved the loss of their four limbs. The blue whale is the largest animal alive. Their ancestors once lived on land; they were shore-dwellers. The blue whale’s ancestors hunted in the water, but slept and lived on land. They returned to the sea around 55 million years ago. They evolved a powerful fluke, stream-line shape, blubber and underwater hearing after returning to the water. The blue whale specifically is one of the loudest animals. Its vocals can travel thousands of miles underwater. Blue whales can weigh up to 400,000 pounds. Blue whales can eat 40 million krill a day, during feeding season. They have the ability to gulp about 17,000 gallons of water at a time.
The whale, according to our class cladogram, evolved a backbone and skull, becoming a vertebrate. Next, the whale evolved a jaw, making it a gnathostome. The whale is also a tetrapod, meaning it had four limbs. The whale evolved a watertight egg, making it an amniote. The whale evolved into the synapsids, which means they evolved a hole behind the eye socket. Next, they evolved a third bone in the middle ear from one in the lower jaw, making it a mammal. The whale then became a placental by evolving the ability to give live birth. The last group on our cladogram the whale fits in is ungulates, which means it evolved hooves.
The whale is most closely related to the horse, mammoth, hylochoerus meinertzhageni, and the Irish elk, on our cladogram. These animals all belong to the ungulates clade. I figured this out by following the whale’s branch to the most recent node. All of the animals that also branched from that node are ungulates, and the whale’s closest relatives. The most advanced trait these four animals share with the whale is the evolution of hooves. I found out what the most advanced trait was by following the whale’s branch back to its most advanced node, ungulates, which is the evolution of hooves. The most important difference between these four animals and the whale is that the whale eventually evolved the loss of its four limbs.
At the American Museum of Natural History I learned that whales lost their front limbs before they lost their hind limbs. There was also another type of whale, other than toothed whales and baleen whales, archaic whales. Archaic whales are now extinct. They had not fully developed their flippers before becoming extinct. There is a large variety of whales living today.
Last updated April 7, 2007.