On Fri, 5 Sep 1997, Hauk Langlo wrote:
> Hello. If I'm not wrong, this is a forum for all kind of people with
> more or less knowledge in different aspects of biology. Before I ask my
> question, I would like say that I have absolutely NO education or
> experience with biology, so please dont laugh to my question.
>> I know that insects and arachnids could be unbelievable big in
> prehistoric times. I know that these creatures are prevented from
> growing bigger than today due to limited amounts of oxygen in the air. I
> also know that some of these insects have been altered by virtually no
> genetic evolution ever since then.
> What if those days environment (oxygen, moist, temperature, light,
> etc.) was simulated in a huge tank or something? (The oxygen level and
> temperature could even be raised above the "30 000 000 BC" standard. And
> the availability of healthy food should also been taken care of, maybe
> spiced up by steroids or other interesting chemicals). Would insects and
> arachnids grow up to be the same gigantic beasts as they once where????
> (Up to 50 cm.)
>> I guess that some boring realities makes the answer a "NO way!". But
> anyway, I would appreciate a comment from anyone who knows a bit about
> these things. It was just an idea that popped up one of these days, and
> I am just curious about the whole thing.
> Hauk "Frankenstein" Langlo
>Hauk.Langlo at stud.hivolda.no> (an ordinary man totally without any biology knowledge whatsoever)
Hello, I'm a Graduate Student at the University of Houston, and I think I
can clarify your quandry. The limiting factor to insect size has more to
do with constraints of an external skeleton then environmental condidions
like Oxegen. Have you ever noticed that very large insects break easily?
It's difficult to repair an exoskeleton, it's not living tissue (like your
hair or fingernails). -The larger the egg, the easyer it breaks, because
the building materials work well at a small scale, but not at a large one.
The largest insects in the carboniferous period were never any larger then
the largest insects today. The giant dragon flies had a wing span of up
to a foot, aproaching the upper limit of what is possible for insects, but
if you take volume into account, there are beetles that are just as large
Oxegen does have an important role in the size of
insects. Most insects resperate (breath) through small holes called
sphericals in thier abdomens. There is a direct correlation between
organism volume, and complexity of breathing aperatus -because small
things diffuse oxigen easily (you need complicated mechanisms to get air
to a-lot of volume). That's why there are not giant ameboas, no giant
single celled bacteria, etc. . . Make sense?
Department of Biology
University of Houston