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Dinesh

Dinesh club

Posted: 24 Jul 2020

Taken: 24 Jul 2020

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Why Evolution is True •
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Figure 8

Figure 8
Invasion of the land. An early lobe-finned fish from about 385 million years ago; a land dwelling tetrapod from Greenland, about 365 million years ago; and the transitional form’Tiktaalik roseae,’ from Ellesmere Island, about 375 million years ago. The intermediacy of Tiktaalik’s body form is mirrored by the intermediacy of its limbs, which have a bone structure in between that of the sturdy fins of the lobe-finned fish and the even sturdiest walking mammals: the bone with darkest shading will become our humerus, and the medium- and light-shaded bones will become the radius and ulna, respectively.
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 Dinesh
Dinesh club
One of the greatest fulfilled predictions of evolutionary biology is the discovery, in 2004, of a transitional form between fish and amphibians. This is the fossil species ‘Tiktallik rosae,’ which tells us a lot about how vertebrates came to live on the land. Its discovery is a stunning vindication of the theory of evolution.

Until about 390 million years ago, the only vertebrates were fish. But, 30 million years later, we find creatures that are clearly ‘tetrapods: four-footed vertebrates that walked on land. Those early tetrapods were like modern amphibians in several ways: they had flat heads and bodies, a distinct neck, and well-developed legs and limb girdles. Yet they also show strong links with earlier fishes, particularly the group known as “lobe-finned fishes,” so called because of their large bony fins that enables them to prop themselves up on the bottom of shallow lakes or streams. The fishlike structures of early tettrapods include scales, limb bones, and head bones. - page 36
4 years ago.

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