Hello David,

I think trying to set criteria for life is like playing a parlor game,
a fun and thought provoking excercise. I don't think the concept is
predictive as a scientific theory ought to be

We are discovering examples of living organisms that are able to shut
down metabolism completely when conditions dictate and resume
metabolism when conditions permit. .

The plant seeds are one instance. There are some fish and frogs that
can freeze solid so all circulation stops and all electrical activity
stops, yet they revive as the temperature rises. Tardigrades is
another example of an animal that goes into extreme metabolic shutdown
and will revive from that state after being subjected to outrageous
and extreme conditions.. We have a bona fide report of tuns being
hydrated and resuming activity after being in the dehydrated state for
120 years. (Brusca, R. C. & G. J. Brusca. 1990. Invertebrates.
Sinauer Associates, Sunderland, Massachusetts. )

Several of the five, six or seven criteria for life are metabolic
processes. . When metabolism shuts down, do these organisms die? I
don't think so, but I also don't think we should play semantic games
with terms like quiescent, dormant and suspended animation. These
terms are not scientific and do not elucidate conditions. If the
organism had died we would observe decomposition of the structure such
that metabolism would never return. IMO, there exists a coding in the
structure of living organisms that needs to be recognized for life to
continue when metabolism shuts down..
..
How do you see the "criteria for life" as being consistent with these
phenomena? I realize there is a catch-all criteria "response to the
environment," however historically that principle has referred to
different properties than raised here.

Aaron

Aaron

On 31 Mar 2004 16:11:54 -0800, (David Hershey) wrote:

"Miss Chanandler Bong" wrote in message . com...
Are seeds alive or not? Seeds have been
found in the desert and that are 4000 years
old, but when put in moist soil, they grow.

So where does the life come from? Is it generated
when conditions are right? Or was the seed alive
but dormant? Do the conditions make life? Can't
find answers - I don't think anyone knows.

A seed that germinates after 1,000 years would have been alive for
those 1,000 years but in a type of suspended animation. It may or may
not have been dormant. A dormant seed will not germinate even when
environmental conditions for germination are optimal. Many seeds are
not actually dormant, but merely quiescent. Quiescent seeds will
germinate promptly when exposed to environmental conditions optimal
for germination. Most flower, vegetable and lawn grass seeds are
quiescent rather than dormant.

Aaron posted some links about the Beal seed longevity experiment.
Fritz Went started a similar experiment in 1947 with seeds sealed in a
vacuum. He intended the experiment to last 360 years.

http://www.ou.edu/cas/botany-micro/b...tracts/1.shtml

Biology textbooks often list from four to seven characteristics of
life. They might be of use in your determination if seeds are alive.

http://128.252.223.112/posts/archive...6518.Bt.r.html
http://128.252.223.112/posts/archive...2472.Bt.r.html

Seeds are often very tough. For long term storage, seeds are routinely
kept at liquid nitrogen temperatures. NASA put thousands of tomato
seeds into orbit for over 5.5 years. The seeds germinated well when
returned to earth.

http://www.worldandi.com/specialrepo...er/Sa20717.htm