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Life came out of the sea? Well some went back

Discussion in 'Open Chat' started by Tim, Dec 20, 2007.

  1. Tim

    Tim Creative Writer

    Joined:
    Jan 16, 2005
    Location:
    England
    A curious article here that kind of dispells the blanket rule that life evolved in the sea and moved onto land.







    Whale 'missing link' discovered

    By Helen Briggs
    Science reporter, BBC News
    [​IMG]

    [​IMG] The animal was small, stocky and about the size of a raccoon

    The whale is descended from a deer-like animal that lived 48 million years ago, according to fossil evidence.

    Remains found in the Kashmir region of India suggest the fox-sized mammal is the long-sought land-based ancestor of whales, dolphins and porpoises.
    Research in Nature suggests the animal lived mainly on land but dived into water to escape predators.
    Whales are known to be descended from land-dwellers but the "missing link" has been a mystery until now.
    Although Indonyus, as it is known, looks nothing like the whales of today, it shares certain anatomical features.
    [​IMG] [​IMG] We've found the closest extinct relative to whales and it is closer than any living relative [​IMG]


    Professor Hans Thewissen


    The structures of its skull and ear are similar to those of early whales, and like other animals that spend a lot of time in water, it had thickened bones that provided ballast to keep its feet anchored in shallow water.
    "We've found the closest extinct relative to whales and it is closer than any living relative," said study leader Professor Hans Thewissen of the Department of Anatomy at Northeastern Ohio Universities College of Medicine in Ohio, US.
    Hippo link
    Indonyus belongs to an ancient order of mammals that had two or four toes on each foot. Modern day representatives of the group include camels, pigs, and hippopotamuses.
    [​IMG] Hans Thewissen holding skull of Indohyus


    DNA studies show that hippos are in fact closely related to modern whales. They do not appear in the fossil record, however, until about 15 million years ago, some 35 million years after the cetaceans originated in south Asia.
    This led Professor Thewissen and his team to search for an older land-based ancestor that would fill in some of the gaps in our knowledge of the whale's dramatic evolutionary journey from land to sea.
    After seeing loose teeth and fragments of jaw bones found by the late Indian geologist A Ranga Rao some 25 years ago, Professor Thewissen obtained rock samples from Rao's private collection. They harboured a treasure trove of complete Indohyus fossils, including skulls and leg bones.
    Dietary clues
    The stable-oxygen-isotope composition of its teeth suggest that the animal spent much of its time in water.
    Some have assumed that the ancestor of whales first took to the water to feed on fish but the latest evidence suggests otherwise.
    "The new model is that initially they were small deer-like animals that took to the water to avoid predators," Professor Thewissen told BBC News. "Then they started living in water, and then they switched their diet to become carnivores."
    Although the behaviour and habits of Indohyus appear somewhat strange, there is a modern day parallel in the African mousedeer (chevrotain).
    The mousedeer lives on land, but is known to leap into the water to avoid predators such as eagles.
     
  2. Kevin

    Kevin Code Monkey Staff Abductee

    Joined:
    Mar 20, 2004
    Location:
    Pennsylvania
    Interesting article as it's a topic that I don't see covered often. I had not realized before that the hippo & whale species are connected!
     
  3. Tim

    Tim Creative Writer

    Joined:
    Jan 16, 2005
    Location:
    England
    When I did A level biology, the images of foetuses, ears and rats all got mixed up. You can see at different stages of development how they could evolve into things.
     
  4. Black Mathias

    Black Mathias Twisted Mentat

    Joined:
    Jun 5, 2007
    Location:
    Under the Sea
    I'd just recently read the same thing. I'd like to add that some of us would like to return to the sea. I think I'm evolving into an "aquatic ape".
     
  5. Starbeast from Planet X

    Starbeast from Planet X Benevolent Galaxy Being

    Joined:
    Sep 19, 2009
    Location:
    Illinois, planet Earth
    I like ancient nature. I know that modern whales were once wolves long ago, the "missing link" was found in the 1990's, a strange looking critter indeed judging by the skelital fossils.
     

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