[extropy-chat] bug evolution

[BillK]

On 11/19/05, spike wrote:
> > The iron in
> > hemoglobin is replaced with copper in insects hence the different color.
>
> Copper!  I'll be damned, I never knew that.  I was
> wondering what one could use bugs for if one were
> to be able to somehow collect a few tons of them,
> such as by building a giant net that sweeps over a
> cornfield.  I had in mind processing them into
> food for shrimp and crabs, but it isn't clear what
> that would do to the taste of the meat.  But if
> it didn't harm the meat, then one might be able
> to collect the waste products of the shrimp or
> crab farms, then chemically extract the copper
> for less than the cost of mining copper the
> usual way.  Thanks John!
>


Don't worry spike. You never knew that because it isn't quite correct. :)

Try googling on insect blood.

In insects, the blood (more properly called hemolymph) is not involved
in the transport of oxygen. (Openings called tracheae allow oxygen
from the air to diffuse directly to the tissues). Insect blood moves
nutrients to the tissues and removes waste products.
So insect blood doesn't need iron or copper.

The greenish or yellowish color of insect blood comes from the
pigments of the plants the bug eats.  Of course, if a recently fed
mosquito splats on your windscreen, it will be full of red animal
blood. :)


Quote:

Small invertebrates

In some small invertebrates, oxygen is simply dissolved in the plasma.
All other animals use respiratory proteins to increase the oxygen
carrying capacity. Hemoglobin is the most efficient respiratory
protein found in nature. Hemocyanin (blue) contains copper and is used
in crustaceans or mollusks. Sea squirts, among other marine life, use
a vanadium chromagen (bright green, blue, or orange) for its
respiratory pigment.

In many invertebrates, these oxygen-carrying proteins are freely
soluble in the blood; in vertebrates they are contained in specialized
red blood cells, allowing for a higher concentration of respiratory
pigments without increasing viscosity.

BillK