X-ray images focus on insect body size
Published: Aug. 13, 2007 at 1:49 PM
ARGONNE, Ill., Aug. 13 (UPI) -- U.S. government scientists have used X-ray images in an attempt to determine why the giant insects that lived millions of years ago disappeared.
In the late Paleozoic Era, with Earth's atmospheric oxygen levels reaching record highs, some insects evolved into giants. But when oxygen levels returned to lower levels, those insect giants became extinct.
Argonne National Laboratory researchers have confirmed the hypothesis that the basis of such gigantism is the insect respiratory system. In contrast to vertebrates, where blood transports oxygen from the lung to the cell, insects deliver oxygen directly through a network of blind-ending tracheal tubes.
As insects become bigger, that type of oxygen transport becomes far less effective. But when the planet's atmospheric oxygen levels increased, as they did during the late Paleozoic, larger-sized insects -- even giants -- evolved.
The research that included scientists from Midwestern University and Arizona State University appears in the Proceedings of the National Academy of Science.
In the late Paleozoic Era, with Earth's atmospheric oxygen levels reaching record highs, some insects evolved into giants. But when oxygen levels returned to lower levels, those insect giants became extinct.
Argonne National Laboratory researchers have confirmed the hypothesis that the basis of such gigantism is the insect respiratory system. In contrast to vertebrates, where blood transports oxygen from the lung to the cell, insects deliver oxygen directly through a network of blind-ending tracheal tubes.
As insects become bigger, that type of oxygen transport becomes far less effective. But when the planet's atmospheric oxygen levels increased, as they did during the late Paleozoic, larger-sized insects -- even giants -- evolved.
The research that included scientists from Midwestern University and Arizona State University appears in the Proceedings of the National Academy of Science.
© 2007 United Press International. All Rights Reserved.
This material may not be reproduced, redistributed, or manipulated in any form.
This material may not be reproduced, redistributed, or manipulated in any form.
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