Far out!! Thanks very much for telling me about this! I would like to find out
what's known and/or speculated about an evolutionary explanation for the fact
that most organisms have a finite lifespan even (presumably) under ideal
conditions. Can you point me toward any references?

Thanks again for the thought-provoking information you've already provided.

Peace


"David Hershey" wrote in message
om...
| It is does seem feasible that some trees could live forever unless
| killed by disease, pests or environmental factors such as drought,
| climate change, wildfire or catastrophic weather events such as floods
| and hurricances. The same trunk would not survive because it would
| eventually decay. However, some tree species are very good at
| sprouting from their base or suckering and would be good candidates
| for immortality. Quaking aspen is often considered "theoretically
| immortal"
|
| http://www.treesforlife.org.uk/tfl.aspen_boreal.html
|
| I posted the following before in sci.bio.botany:
|
| A single quaking aspen (Populus tremuloides) clone can spread via root
| suckers to cover 100 acres or more. One quaking aspen clone in Utah
| named 'Pando' has been estimated to be 80,000 years old.
| http://www.nps.gov/brca/quaking_aspen.html
|
| Mitton and Grant (1996) stated that a quaking aspen clone can exceed a
| million years in age. 'Pando' has been considered the most massive
| living organism. It might be the oldest plant as well.
|
| Reference
|
| Mitton, J.B. and Grant, M.C. 1996. Genetic variation and natural
| history of quaking aspen. BioScience 46:25-31.
|
| David R. Hershey
|
|
| "Elaine Jackson" wrote in message
news:Aui9d.19220$a41.9801@pd7tw2no...
| From what I understand (to save time let's agree that this qualification
applies
| to all of what follows), there are certain plants that have a finite
lifespan
| built into them: they go to seed and then they die. (Incidental question:
does
| such a lifespan always coincide with a single solar year?) Then there are
| animals, who have decrepitude built into them instead: it can't be put off
| indefinitely, and once it starts, it continues until the animal is too
feeble to
| survive.
|
| Please comment on anything that's incorrect so far.
|
| My main question is: What about trees? I can't recall ever hearing of a tree
| that died of old age. They continue growing throughout their lives, but is
there
| anything about perpetual growth that necessarily leads to death? (Incidental
| question: How does a tree's growth rate change over the course of its life?)
| Obviously something will get them eventually, just because life is a gamble
and
| every lucky streak has to end. But, in principle, could a tree live forever?
|
| Any help greatly appreciated.
|
| Peace