>Could you please include:
>
>1) Development of biochemical processes step by step showing adaptive
>utility of each step.
>Photoactivity must be connected to a set re-set mechanism and must be
>connected to the
>neorological system in some fashion.
Explaining this would require a lot of patience on your part, as someone
has to find out what all the biochemical processes are in the first place,
and I have to read them as well as finish my dissertation and get a job. I
am not a biochemist, so I do not know what is known about all of these. I
believe there are some ideas on the evolutionary precursors of
photosensitive pigments, but do not remember any detail. I can describe
the biochemical evolution of primate red-green color vision, if that would
be of interest.
From a morphological point of view, any sort of eye from a single
photosensitive cell on up is useful. The wide range of eye types in living
and fossil organisms suggests that there are quite a few genetic
combinations that would be functional intermediates.
For the most simple eye function, all that is needed is a connection to the
appropriate response function. A brain is not necessary, just a neuron.
For example, the ark shell in the aquarium that closed its valves when I
walked past diid not have a brain. It did have simple eyes, enabling it to
detect a moving shadow, and some sort of connection to the adductor muscles
to send the message, but no image processing. Even its eyes are well ahead
of the simplest.
>Also, I want to know the purported time frame for these mutations. That
>is,
>according to the geological record, every so often a nasty rock from
>space kinda messed
>things up.
The oldest fossil eyes I know of are on Early Cambrian arthropods. These
are moderately well-developed, suggesting older eyes existed. As soft
parts, they do not necessarily fossilize well. The genetic mechanism
builds on similar precursors in all bilaterian animals, but it is unknown
whether this means that the ancestor of all bilaterians had very primitive
eyes or whether it simply had a gene useful towards that end, which evolved
in parallel in different groups.
Complex eyes have evolved several different times. They also have been
lost multiple times, making it difficult to tell exactly when they evolved
in what group. Scallops have eyes but the glass scallops do not. However,
glass scallops are predominantly deep water species, where eyes are not
very useful. No fossil soft parts are known for scallops, so it is not
sure whether scallops evolved eyes after they separated from glass scallops
or whether the ancestral form had eyes and glass scallops lost them. Thus,
the timing of the evolution of eyes in scallops is not very clear.
Overall, the timing of eye evolution could have, as a maximum, between a
billion and half a billion years. Groups such as the scallops have
apparently evolved less complex eyes in a shorter period of time.
>as all
>> the intermediate steps are useful,
>*********
>
>WOW. This is a great assertion. Want to support it with someting.
>Please, fill us in.
Again, I was thinking of the morphology. Even rudimentary eyes are useful
for any organism not always in total darkness. If you can see something,
you can respond to it. If you can see more clearly and have the mental
ability, you can respond more precisely.
>Reduction in the utility of an existing function is not very
>convincing. You
>still have a great processing unit collecting even mitigated
>information.
My point was not clear. If something evolved to the point of seeing as
well as I do without glasses, it would be able to get a lot of informaiton
from that. If it evolved better vision than that, it could get more
information without having to hold things within a few inches of its eyes.
> Really, can you count the bytes of information in
>the eye
>for example and then estimate the number of bytes of information that
>could
>be generated per generation and then the number of generations.
>Something
>to hang this on, just something.
A rough number of generations would be a few hundred million.
I'm not sure how to estimate the number of bytes that would be equivalent
to the genetic code. The order as well as the base can be important.
However, a lot of rearrangement and substitution are possible without
changing the result. Large pieces of DNA can be duplicated in a single
generation, greatly increasing the amount of data, but then mutations must
occur in the relevant genes for anything novel to appear. For example, red
and green color vision in primates is the result of a duplication and
slight mutation in the ancestral gene. It does not take too much of a
change in a molecule to shift the wavelength to which it is sensitive, so
development of color vision by such mutations is not too surprising.
David C.
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