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 | | From: | neha | | Subject: | transparent creatures | | Date: | 28 Dec 2004 08:13:33 -0800 |
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 | hi everyone,
can anybody tell me about the anatomy of transparent
fishes (like jellyfish, larvae of many fishes) OR their anatomical
characteristics which make them so transparent.
if it's not possible to tel d details by mail, then please
do sugest me some good sites to which i can refer this topic in detail.
waiting for reply. thanks.
neha:)
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| | From: | Rocco Moretti | | Subject: | Re: transparent creatures | | Date: | Tue, 28 Dec 2004 12:10:14 -0600 |
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| neha wrote:
> hi everyone,
> can anybody tell me about the anatomy of transparent
> fishes (like jellyfish, larvae of many fishes) OR their anatomical
> characteristics which make them so transparent.
> if it's not possible to tel d details by mail, then please
> do sugest me some good sites to which i can refer this topic in detail.
> waiting for reply. thanks.
>
> neha:)
sci.aquaria is not very active, so you might have better luck asking
elsewhere. That said, I'll take a crack at answering your question. (I'm
assuming you're a grammar school student, and aiming my answer at that
level. Please forgive me if I'm mistaken.)
What makes them transparent is not any particular feature they *have*,
but what they lack. They simply lack anything that absorbs or refracts
light.
Look at your hand. Unless you're sick, it will probably be some shade of
reddish-tan to reddish-black. That's due to two things: melanin and
hemoglobin. Melanin, depending on the type, is a
black/brown/reddish-brown pigment that protects you from the sun. If you
took away the melanin, humans would be a lot lighter and clearer, but
we'd also sunburn easier. Under water, you don't need as much protection
from the sun, so creatures can do away with the light protecting pigments.
The reddish hue is from hemoglobin and myoglobin, the oxygen
carrying/storing pigments. Vertebrates use the 'globins, but other
creatures have different ways of transporting oxygen, and may have green
or even colorless "pigments" in oxygen transport.
If you take out those two types of pigments and a handful of minor ones,
you would be mostly colorless. You would, however, be a milky white
color. That's not due to any pigments, but is due to refraction. When
light moves through something clear and hits something else which is
clear, it refracts, or bends. If you have a bunch of these changes in a
small space, the effect is to mix up the light that is going through the
object. That's why a pile of snow/sugar/salt is white. The
ice/sugar/salt is clear by itself, but you have all these air->ice->air
changes in a small space, which mixes up the light and looks white.
If all of the organism is pretty much the same (as measured by the
"index of refraction" or IOR), then the light doesn't bend much at all
as it passes through it, and it's transparent. For creatures like
jellyfish, they are all mostly the same inside, so they look
transparent, and since they don't need any pigments, they are colorless.
Hope that gets you started in understanding ...
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