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Location: UFOUpDatesList.Com > 2010 > Oct > Oct 9

Re: Shostak's Search Shift?

From: David Rudiak <drudiak.nul>
Date: Fri, 8 Oct 2010 10:43:39 -0700 (PDT)
Archived: Sat, 09 Oct 2010 07:59:45 -0400
Subject: Re: Shostak's Search Shift?

>From: J. Maynard Gelinas <j.maynard.gelinas.nul>
>To: post.nul
>Date: Thu, 7 Oct 2010 18:38:57 -0400
>Subject: Re: Shostak's Search Shift?

>This post is a combined response to David Rudiak, Stanton
>Friedman, and Jerome Clarke. My apologies for not responding
>sooner as I've been ill. I'm responding in this manner simply to
>cut back on redundant replies to the List. I'd like to thank
>each of them for taking the time to respond, even if each
>staunchly disagree with my position. And I also recognize that
>as a newcomer here, I'm challenging several. very well known and
>highly respected researchers of this topic. This is not meant to
>be personally disrespectful.

>To start with, David Rudiak responded to my argument against
>evolutionarily common bilateral bipedalism. Here is the salient
>portion of David's reply

>>From: David Rudiak <drudiak.nul>
>>To: post.nul
>>Date: Mon, 4 Oct 2010 10:23:23 -0700 (PDT)
>>Subject: Re: Shostak's Search Shift?

>>This point keeps coming up, that there are supposedly strong
>>scientific arguments that (biological) space aliens would not be
>>humanoid but some other unimaginable form. These arguments are
>>neither strong, informed, nor particularly scientific, at best
>>highly speculative, and also at odds with what we observe
>>evolution creating here on planet Earth, where natural selection
>>forces in particular environmental niches produce many examples
>>of convergent evolution of form. Or as the jingle goes, form
>>follows function.

>Hi David, thank you for your reply. Of course, I'm not a professional
>Evolutionary Biologist, so please understand if I make an error.
>However, I think your argument rests on a shaky foundation. Allow me
>to repeat your point in my own words, so we both know our various
>assertions are understood by the other. My interpretation is that you
>are arguing that because some morphological forms show repetition
>across varying Earth environments, that such might be the case across
>extraterrestrial planetary environments. For example, mammals Europe
>and North America might have a marsupial homologue in Australia.
>Here's a web site that discusses common evolutionary traits between
>mammals and marsupials:


>So, on the one hand you're correct. Certainly, across two
>isolated habitats similar morphology to fill in similar
>ecological niches evolved. However, I think there's a flaw in
>your argument. First, you ignore just how close mammals and
>marsupials are to one another on the evolutionary tree compared
>to - say - long since extinct organisms from the Pre-Cambrian
>and Cambrian era.

I wasn't comparing mammals and marsupials, which are indeed very
closely related, though even here there are interesting examples
of convergent evolution of form, such as the Australian lion and
big mammalian cats.

Instead I made some comparisons across some widely disparate
species in evolutionary history with some similar morphology,
e.g. flying insects and birds or ichthyosaurs (reptiles) which
evolved 150 million years before and looked almost identical to
modern porpoises (mammals). In addition to many common
morphological structures, both evolved from land animals and
gave birth to live young, yet again far removed from one another
in the evolutionary tree.

The point is again, with similar ecological niches, form follows
function. There are a limited number of optimal solutions for
survival in particular ecological niches. Another example,
predators often have forward-looking eyes (with good binocular
vision) while prey have their eyes off to the side to give them
a much wider field of view to look for predators.

>This is a critical point, as many organisms
>from that period do not follow bilateral forms. Most organisms
>from that period are long since extinct.

Actually very little is known about pre-Cambrian life forms
since they were soft-bodied and didn't leave much fossil
evidence behind. But I think you miss the big picture with your
argument. There aren't a lot of geometrical symmetries to work
with: radial, spherical, and bilateral (or no symmetry, such as
sponges). All existed pre-Cambrian just as they do post-

But ONLY bilateral symmetry results in streamlining and rapidly
moving life forms. Bilateral symmetry is also more energy
efficient for motion. Speed and energy efficiency both have
highly significant survival value, which is why they were
selected for. (Streamlining and energy efficiency is also why
nearly all our craft, from canoes to submarines and jet
airplanes are bilaterally symmetric--it is an optimal solution.)

Those are the primary reasons why all higher and more complex
life forms are bilateral symmetric, and it isn't going to matter
which star system they evolve in. Bilateral symmetry is going to
be king because of basic physics that is the same everywhere.

Bilateral symmetry also leads to the development of a head end,
nervous systems, and concentration of key sensory systems in the
head end.

All surviving spherical and radially symmetric life forms are
rather inert or sluggish and none have complex nervous or
sensory systems. They've had just as much time to evolve
something interesting as the bilaterally symmetric forms, but
obviously these symmetry forms are evolutionary dead ends in
terms of complexity. So don't expect an alien star fish to step
out of a space ship and shake "hands" with you.

>The question then
>becomes, did they go extinct by chance, selecting one set of
>branches on the tree of life for Earth's current set of
>organisms, or did they go extinct because such forms are
>unsuitable across most environments?

They didn't go extinct. They are still with us. They just didn't
go anywhere exciting or complex. Bilateral symmetry is
inherently superior.

>We won't know the answer to
>that question until we've surveyed life and its progenitors
>across several exoplanets.

Nope, isn't going to matter.

>But right now I'd bet that most
>professional evolutionary biologists would argue that former and
>not the latter. That is was random chance that led to the
>prevalence of bilateralism here on Earth.

Nope. Again bilaterally symmetry inevitably leads to faster,
more efficient, and more complex life forms. Radial and
spherical symmetry does not. Chance has nothing to do with it.
Doesn't matter where you are.

>So, my counterargument to you is that while homologous form
>across isolated ecological niches may be prevalent on Earth,
>such as mammalian and marsupial forms, that is only because they
>were so close on the evolutionary tree to begin with. Thus,
>extrapolating similarities between mammals and marsupials in
>order to argue for similarities between evolved organisms on
>Earth to other unknown exoplanets may not be a valid argument.

Sorry, but I never argued similarities between mammals and
marsupials, so I don't understand why you keep saying that is
the foundation of my arguments. I was arguing more general
principles, such as the superiority of bilateral symmetry, or
why major sensory systems like vision and hearing will
necessarily concentrate near the head end. All of these have
highly significant survival value.

There was also the important restriction of dealing with
technological beings capable of building space ships. So they
better have something like big brains with good vision and
appendages for fine manipulation, which also implies a certain
minimal size and something like an internal skeleton for
continued growth to that size. They also must necessarily be
mostly land animals, unless you can figure out how to build
fires and smelt metals underwater. So don't expect to shake
hands with alien porpoises or octopi either, although alien
amphibians might be a possibility.

All such arguments apply to animals that would evolve in the
natural world. If we were dealing with cybernetic beings instead
that evolve outside of natural selection, then morphological
forms could be wildly different.

David Rudiak

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