archive: Re: SETI Why would anyone look forward to sharing this galaxy?

Re: SETI Why would anyone look forward to sharing this galaxy?

jerry and judy ( )
Fri, 9 Oct 1998 13:06:14 -0600

>As an evolutionary biologist who has studied both plant evolution
>(paleobotany) and animal evolution (vertebrate paleontology) for most of
>his professional career (25 years), I have followed closely those
>paleontologists who are interested in dinosaurian evolution. I have watched
>various scientists debate whether the dinosaurs walked upright or walked
>like crocodiles, whether they were cold blooded or warm blooded, or
>something in between, and whether or not birds evolved from dinosaurs.
>Until recent discoveries in Spain and China, there was insufficient
>evidence to support the nay sayers or the yeh sayers regarding the
>avian/dinosaurian connection. The new discoveries are discussed in a
>well-illustrated article in National Geographic (July, 1998), called
>"Dinosaurs take wing, the origin of birds." The new discoveries do a lot
>for the skeptics, who must now eat humble pie. They also teach us the
>perils of speculation and skepticism based on too little data.

You're right, of course, (I'm a retired meteorologist and I worked my last
ten years in ozone depletion monitoring and research with a government lab
and participating universities, talk about dangerous speculation! and
stultifying skepticism!), but I know of no such 'perils' in a newsgroup,
brought on by speculative banter. :)

>On the subject of whether or not the dinosaurs would have been 20 million
>years ahead of us in space exploration, had they evolved into sentient
>intelligent technological beings such as ourselves, it is noteworthy that
>the dinosaurs are not extinct, they are not as advanced as us, and they are
>feathered! That does not mean that our favorite giants such as
>Tyrannosaurus survived in feathered disguise (although some paleontologists
>think that close relatives may have), but rather that some members of the
>Dinosauria did things differently. The fossil record is very fickle in
>yielding up its secrets. After their big brothers became extinct, the
>winged survivors successfully competed with mammals over the past 65
>million years.

I don't understand how the emergence of pre-birds, 170 million or more
years ago, effects the mental potential of Dromaeosaur's descendents after
some 65 Myr ago. The two groups are no more closely related than mice and
bats, which haven't shown any sign of converging since they diverged 60
million years ago. I must not understand your point.

> What may have led us to learn how to fly using technology
>was them, because they were ahead of us in that skill. What may have
>prevented them from evolving into highly intelligent animals may be
>limitations imposed on evolution due to specializations for flight. Flight
>gave them a convenient escape from predators, but flight also limited brain
>development through weight constraints and tool use by the specialization
>of their front two appendages (however, there are some birds quite adept at
>using their feet to hold objects, and some of them have learned how to use
>sticks as tools). Land-dwelling mammals, on the other hand, had to
>outsmart their adversaries to survive, which placed evolutionary pressure
>on brain development.

Yes, the special developments and energy requirements that are needed to
make for efficient flight are probably irreversible (populations adapt to
local conditions and have no *care* about future potentialities). Birds
very quickly loose the ability on remote predator-free islands, so it seems
the costs of flight are very high.

>Evolution is a funny thing. You can never predict its outcome, only its
>possible options given a set of environmental conditions and challenges.
>Had bipedal dinosaurs survived which had not evolved feathers and flight
>capability, perhaps things would have been different. But in order for
>similar creatures to evolve on other planets, conditions probably would
>have to be very Earth-like.

Depends on what you mean by 'similar' creatures and what you mean be

Maybe tens of millions of years of arboreal existence (or the like) are a
prerequisite for the brain development which then can be shaped by
bipedalism and 'tool-making'. Maybe Dromaeosaur's descendents wouldn't
have had enough of the right stuff to work with anyway. Just speculation,
but it might mean that we are very special and very alone (and very safe!).

>Yours truly,
>Bruce Cornet, Ph.D.
>Geologist and Paleontologist

Thanks, Jerry

I'm interested in the evolutionary lines of descent of North American
conifers. Are there any recent books or online references that you can
recommend? Thanks.