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What evidence supports the theory that whales evolved from land mammals?
Fossil evidence
Fossil evidence suggests that whales evolved from land mammals. Using comparative DNA techniques, scientists have also suggested that whales are related to hippos. How could comparing amino acid support the theory of evolution?
How do scientists know whales evolved from mammals?
But scientists knew that whales descended (evolved) from four-footed land mammals because whales and dolphins still have some features of land mammal: they use lungs to breathe air and give birth to young that are nursed by milk. These animals are now thought to be true whales ancestors on land.
What do scientists think was an ancestor of whales?
The ancestor of today’s whales, the first cetacean, is believed to be Pakicetus, a quadruped measuring 1 to 2 metres long. Skeletons discovered in Pakistan indicate that the animal had typical artiodactyl ankles and a typical cetacean skull.
How do you think whales evolved?
Both hippos and whales evolved from four-legged, even-toed, hoofed (ungulate) ancestors that lived on land about 50 million years ago. Unlike the hippo’s ancestor, whale ancestors moved to the sea and evolved into swimming creatures over a period of about 8 million years.
How did scientists use fossils to solve the mystery of whale evolution?
Starting in the late 1970s, a growing number of fossils have allowed scientists to piece together the story of whale evolution. The fossils represent ancient, whale-like animals. They show that an ancient land mammal made its way back to the sea more than 50 million years ago. It became the ancestor of modern whales.
What group of artiodactyls gave rise to whales?
Archaeocetes had a “double-pulley” astragalus, confirming that cetaceans had evolved from artiodactyls. Mesonychids were not the ancestors of whales, and hippos are now known to be the closest living relatives to whales. Recently scientists determined which group of prehistoric artiodactyls gave rise to whales.
How did whales evolve into aquatic mammals?
There was no straight-line march of terrestrial mammals leading up to fully aquatic whales, but an evolutionary riot of amphibious cetaceans that walked and swam along rivers, estuaries and the coasts of prehistoric Asia. As strange as modern whales are, their fossil predecessors were even stranger.
Why do marine mammals exist?
The marine mammals exist because about 50 to 60 millions of years ago, some mammals wandered off of the land and into the ocean, and there they evolved into different types of marine mammals. For whales and dolphins, their front legs turned into flippers.
Is a whale a fish or mammal?
Like mammals, whales and dolphins breathe air through a pair of lungs, they are warm-blooded, their young drink milk, and they have hair (although very little). The whale is actually the closest living relative of the hippopotamus. So whales are indeed mammals and not fish!