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Re: How large insects may have come about
The leading theory is that ancient bugs got big because they
benefited from a surplus of oxygen in Earth's atmosphere. But a new
study suggests it's possible to get too much of a good thing: Young
insects had to grow larger to avoid oxygen poisoning.
Were _all_ insects that large in those times???
This may be because insect larvae typically absorb oxygen directly
through their skin, so they have little or no control over exactly
how much of the gas they take in. [...] One way to decrease the risk of
oxygen toxicity would have been to grow bigger, since large larvae
would absorb lower percentages of the gas, relative to their body
sizes, than small larvae.
Another would be to grow a thicker cuticle...