December 21, 2012
Evolution of Whales So we ask ourselves these anonymous questions, where did whales first originate from? How are they able to breathe through such a hole and fill their lungs with air? How is it that such a huge mammal can survive its entire life under water? Whales are large, intelligent, and aquatic mammals. They spend their entire life under the deep blue sea. Like all mammals whales are warm blooded, breathe through their lungs, have hair, and also have a four chambered heart. Whales give birth to their young which are supplied with milk, and they do not lay eggs. Many people have their different opinions on how whales first originated, but only fossils and evidence can prove them as facts. First we look at who really discovered the features on whales. "Whales are known to be an offspring of land animals because of their physical characteristics: bones found in their flippers which resemble forelimbs of land animals, and movement of the spine which resembles an running land animal. In 1963, a man by the name of John Ray realized that whales were mammals and not fish. In 1883, William Henry Flower discovered that whales have vestigial features, which confirmed that whales evolved from terrestrial animals rather than land animals today."¹ Although these two men made these realizations, it wasn't enough evidence to tell us how whales were first made. So now the only thing that scientist could look back on was fossils. A man by the name of Philip D. Gingerich traveled all over the world, and discovered different forms and evidence to the evolution of whales. He explained, " My research on the origin and early evolution of whales is focused on archaeocetes. Pakicetus, known only from the skull and lower jaw, was then the oldest known archaeocete. Rodhocetus is interesting and important in having a large pelvis connected to the vertebral column, but the sacral vertebrae in this connection are no longer completely fused, and Rodhocetus kasranii appears to be an intermediate showing how the sacrum became disarticulated to make the back flexible as it is in tail-powered swimmers like Dorudon and later whales. The femur is preserved on one side of the original Rodhocetus kasranii skeleton, but with this exception, the forelimbs are missing, the hind limbs are missing, and most of the tail is missing."² As Philip D. Gingerich explained, he confirmed that whales once had forelimbs and hind limbs.
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