Skeletal Evolution
Today, the whale hind parts are internal and reduced. Occasionally, the genes that code for longer extremities cause a modern whale to develop miniature legs (known as atavism).
Whereas early cetaceans such as Pakicetus had the nasal openings at the end of the snout, in later species such as Rodhocetus, the openings had begun to drift toward the top of the skull. This is known as nasal drift.
The nostrils of modern whales have become modified into blowholes that allow them to break to the surface, inhale, and submerge with convenience. The ears began to move inward as well, and, in the case of Basilosaurus, the middle ears began to receive vibrations from the lower jaw. Today's modern toothed whales use the 'melon organ', a pad of fat, for echolocation.
Read more about this topic: Evolution Of Cetaceans
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“The evolution of a highly destined society must be moral; it must run in the grooves of the celestial wheels.”
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