C. Tetrapods are more closely related to each other than to non-tetrapods. But some tetrapods returned to the water, regaining that distinctly fishy attribute. The First Whales . Crucially, though, the anatomy of this mammal's inner ears closely matches that of modern whales, the main "diagnostic" feature … The history of these hairy creatures goes back about half as long as fish: they appeared on the earth about 180 to 200 million years ago. Many species we see today, like the snakes or whales, may not appear to be tetrapods, but their lack of well-developed limbs is a secondary adaptation to their habitat. when two groups of organisms independently evolve similar adaptions. Tetrapods are not fish because they aren't aquatic, but whales are tetrapods which are aquatic, and I therefore declare them fish. A tetrapod is any animal that is decended from a common ancestor with four limbs. Since the tetrapods (mammals, reptiles, birds, and amphibians) first left the oceans, many, many different groups of them have returned to take advantage of the food that lies there. The term “tetrapod” refers to land-living animals such as hawks, frogs, and turtles. After they nursed under water. It was only about 10 million years after this extinction—and more than 250 million years since the earliest tetrapods crawled out onto land—that the first whales evolved. Whales on the other hand are mammals, a wholly different class of vertebrates. Tetrapods are therefore a sideline taxon of fishes that moved onto land and into the air, with some groups such as turtles, whales, and seals returning to an aquatic existence. Whales are tetrapods, but living whales do not have 4 limbs. A. Tetrapods — including the modern forms of amphibians, reptiles, birds, and mammals — are loosely defined as vertebrates with four feet, or limbs. The first returns to the ocean may have occurred as early as the Carboniferous Period [20] whereas other returns occurred as recently as the Cenozoic , as in cetaceans, pinnipeds … These are the whales. For a mutation to affect evolution, it must: C. Be able to get passed from parent to offspring. Marine tetrapods are tetrapods that returned from land back to the sea again. What is convergent evolution? Tetrapods — From Water to Land. On an evolutionary time scale, whales are just babies, having appeared only about 50 to 60 million years ago! Snakes evolved from lizards and these are tetrapods. What is a more accurate was to describe tetrapods? The evolution of whales is a story of adaptation and natural selection, but it’s hardly unique. animals that descended from a four-limbed ancestor. Tetrapod. So we say the tetrapods, the fish that left the water, are no longer fish. Tetrapods are a sub-group of animals known as Sarcopterygii. 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