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Dinesh

Dinesh club

Posted: 23 Nov 2023

Taken: 06 Mar 2021

5 favorites     1 comment    29 visits

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Page137 •
From •
Evolution •
The triumph of an Idea •
Carl Zimmer •
Author •

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this photo by Dinesh

Paleontologist Phil Gingarich (left) has discoverd ancien whales with legs in Egypt (shown here) as well as Pakistan

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. . . . paleontologists found a steady supply of fossil of wales, but even the oldest specimens, dating back more than 40 million years, were fundamentally like whales today. They had long backbones, hands in the shape of flippers, and no back legs. Their teeth were another matter, though. Living whales have either no teeth or simple pegs. The oldest whales had teeth that had the cusps and bumps of mammals on land. They looked particularly like the teeth of extinct line of mammals called mesonychids. These animals were hoofed mammals – relatives , in other words, of cows and horses – but they had powerful teeth and strong necks adapted for a life of eating meat, which they got either by scavenging or hunting. ~ Page 136


In the border zone between land and sea, many species of walking whales arose. Some were adapted for wading, others for diving. For the most part these lineages became extinct, for reason that may never be known. But one lineage of whales adapted to life farther out to sea. It produced species such as Rodhocetus, a whale Gingerich found in Pakistan that had stu;bby legs and hips that were barely connected to the spine. In the water it could have raised and lowered its tail and trunk together, swimming like whales do today. Modern whales vastly improve their swimming performance with the flukes at the end of their tails, made of connective tissue. Because that sort of flesh rarely fosslizes, no one known if Rodhocetus already had flukes to help it along. ~ Page sd139/140

Stephan Fey, Paolo Tanino, Pics-UM and 2 other people have particularly liked this photo

Comments
 Nora Caracci
Nora Caracci club
very interesting !!!
hFF & WE !
6 months ago.

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