Re: Why Were Prehistoric Insects Huge?
- From: BradGuth <bradguth@xxxxxxxxx>
- Date: Sat, 11 Aug 2007 12:39:10 -0000
On Aug 8, 10:13 pm, "George" <geo...@xxxxxxxxxxxxxxx> wrote:
http://www.sciencedaily.com/releases/2007/08/070806112323.htm
Science Daily - Alexander Kaiser, Ph.D., of Midwestern University's
Department of Physiology, Division of Basic Sciences, was the lead author
in a recent study to help determine why insects, once dramatically larger
than they are today, have seen such a remarkable reduction in size over the
course of history.
"There were hundreds of ideas to explain the small size, but none of them
could be proven," Dr. Kaiser said. To test their theory that it was an
insect's respiratory system that limited its size, he and his colleagues
launched an extensive study using beetles and fruit flies.
The study, much of which was performed at Illinois' Argonne National
Laboratory, involved the examination of various beetles' respiratory
systems, using new x-ray beam technology to help determine how they
breathe.
Findings show that Dr. Kaiser and his colleagues are on the right track in
their theorizing. Insects breathe through a network of air filled tubes
that deliver oxygen directly to the cells. These tracheal tubes, especially
in the leg, take up more room in larger beetles.
"More than 300 million years ago, there was 31 to 35 percent oxygen in the
air," Dr. Kaiser said. "That means that the respiratory systems of the
insects could be smaller and still deliver enough oxygen to meet their
demands, allowing the creatures to grow much larger."
Dr. Kaiser and his team plan to conduct similar studies in the future using
more ancient species such as dragonflies, since beetles and fruit flies are
considered relatively "new" species in comparison.
Note: This story has been adapted from a news release issued by Midwestern
University.
At mutiple times, and on behalf of promoting diatoms, how many suns
did Earth have, and otherwise at 35% O2 what sort of atmospheric
pressure are we talking about?
Are we talking about a monoseason Earth? (Earth w/o seasonal tilt)
- Brad Guth
.
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- Why Were Prehistoric Insects Huge?
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