How come life spans of all plants and animals are so short when compared to geologic time?

[raccoon]

The longest I know of an animal living is, some tortoises live maybe several centuries.

But that's nothing compared even a THOUSAND years....

[itsrobert]

1. The more do-dads on a car

the more more maintenance needed?

[lumberjack_jeff]

2. Because we're on fire.

Literally. We burn fuel to sustain chemical processes.

[The_Commonist]

8. How come there is no...

"Like" button as on Facebook?

We also rust.

[zipplewrath]

3. No purpose

There is no evolutionary preference for long living. Quite the opposite, there may be some detriment to it, mostly in terms of food supply. Additionally, if the gestation and birth rate adjust for extremely long lives, it makes the organism very susceptible to extinction from short term environmental pressures. Until there is some benefit, based upon learning mostly, that can come from long lives, it isn't clear why evolution would tend to favor it. Even then it would be of limited benefit since 40 year old knowledge may be of very little use.

[Speck Tater]

4. Or looked at from the opposite persepctive, short life spans make it possible

for a species to adapt to environmental changes more quickly. Rate of adaptation is measured in generations, so the more generations that can be fit into the span of some major climate or other environmental change the more likely the species will successfully adapt rather than going extinct.

I know that's essentially the same thing that you said, but I'm just looking at it from a different angle.

[Ready4Change]

7. That was my thought too.

A short lifespan allows faster evolution.

May be outweighed by loss of individual experience. (Animals can learn to be 'shy' of dangerous conditions, like around crocodile filled watering holes, or need time to learn hunting or other food gathering techniques from parents. The idea that elephants have good memories comes to mind.

[zipplewrath]

18. There's alot of study on this

Extremely short life spans have their advantages, but it can result in adaptation to very temporary environmental conditions that then depart as quickly as they arrived.

What is interesting to note is that the physically larger an organism is, the longer the life tends to be, but that isn't anything close to a "one to one" correlation. Gestation tends to run this way as well. And of course there are some very long lived plants out there.

The way things tend to work, we'll probably find some organism some day that lives for centuries, but it will probably do so in some very odd environment, probably one that is VERY isolated, such that its environment isn't very dynamic, and we don't contact that environment very often. Comets and meteors come to mind, or very VERY deep caves.

[Uben]

5. Because life requires certain conditions

...and those conditions are in a constant state of change.

[targetpractice]

6. Read "The Selfish Gene" by Richard Dawkins

It's a great book, and introduces the concept that evolution acts upon genes, not individuals or populations... And, genes are immortal. So, organisms are just survival machines for genes and life is about copying genes... So, organisms have evolved lifespans that balance genetic variation with genetic reproduction. Immortal organisms would not evolve... since genetic variation is only passed onto the next generation and is compounded over many generations. The longer the lifespan for an organism, the slower that kind of organism takes to evolve.

[Peace Patriot]

9. But immortal organisms with brains capable of understanding and manipulating genetics

could evolve themselves by design. In fact, I think that's where things are going, with humans. The problem that may arise, however, is the same problem we have had with being too clever by far, as to invention, while lacking 'evolved' wisdom about our impact on the environment (or ignoring the wisdom that has evolved in small farming communities). Are we going to make as big a botch of genetics as we have of industrialization? Nature seems to 'work' by variety--by creating a cornucopia of forms. Will we create human genetic monoculture--a la Big Ag and its ugly (disastrous) massive fields of one crop? Are we going to create a society in which the super-rich live forever and the 'drones' die? (--the ultimate fascism?) Or are we going to learn true wisdom about Nature's cornucopia, when it comes to ourselves and our awesome intellectual and technical abilities?

[targetpractice]

13. That would be a new type of evolution...

...not "evolution by natural selection"... It's possible that could happen... Dawkins points out that passing genes onto the next generation was the only method of information transfer on this planet until man developed language... Genetic transfer of information only happens from one generation to the next, of course.

[Grown2Hate]

15. That's the book that made me see the light. First scientific book I read after a life of being

raised in a cultish christian religion (Jehovah's Witnesses). I read it and thought, "Holy SHIT, this actually makes SENSE." I've read every one of his books since. I thank Douglas Adam's for turning me on to him. :)

[targetpractice]

21. An epiphany for me, too...

I follow Richard Dawkins these days on Twitter, but I've been meaning to investigate how his theories may have matured since The Selfish Gene... If I remember correctly, he wrote off homosexuality as something that didn't quite fit into the inclusive fitness model, but it actually does.

Also, I've wondered if Dawkins would consider modern corporations as "survival machines" that compete and evolve like genes and memes.

Your thoughts?

[phantom power]

10. I can think of a couple possible reasons

1) The solution sub-space for an organism that lives a long time is small, and/or diffuse, and/or hard-to-reach, relative to the larger space of survivable organisms.
2) An organism that *might* live a long time may still get cut down by predators, disease, and/or natural disasters -- see also in combination with (1).
3) The world is always changing. Any single organism will eventually find itself mal-adapted, if it lives long enough.

[Posteritatis]

11. There's a few actually amortal critters

A couple species of hydras and some clams generally don't grow old in any way we'd recognize and could theoretically last forever. In practice, sooner or later you're going to starve, or fall ill, will succumb to accumulated minor injuries, or be on the wrong side of a rockslide or a flood or a falling tree or lightning, or be found most delicious indeed.

[bananas]

16. Immortal, not amortal

there are also immortal fungi and cancer cells.

[Posteritatis]

17. Nah, I used my wording on purpose

Immortal precludes the possibility of, say, starvation or death by illness; these guys just don't break down barring those, injury, or predation, which is a little less perpetual.

[laconicsax]

12. There are clonal species that live for thousands of years.

The bristlecone pine, for example.

There's also a aquatic plant, Poseidonia oceanica, a colony of which has been dated to around 100,000 years.

It's also a good thing that lifespans are usually measured in years and decades. One reason is that evolution can only act on breeding populations, and a species that lives for millions of years wouldn't likely reproduce all that often. If the average lifespan of mammals was 2 million years, with each generation overlapping that by 1 million years, there'd only have been about 65 generations between the extinction of the dinosaurs and today--hardly enough time for mammals to diversify into what we have today.

Another reason that geologic-scale lifespans wouldn't be desirable also relates to evolution--a species which reproduces every year can survive relatively sudden environmental changes better than one which reproduces every million years. When you look at the history of our planet on a geologic time scale, dramatic changes occur rapidly and an extremely long-lived species wouldn't likely be able to cope.

[dimbear]

14. Species that reproduce by fission don't die.

They welcomed the sun's rays during the Oligocene, and they're still doing it.

[Swede]

19. Some insects live only a day,some fish one year.

I think it's just nature doing it's thing.

[targetpractice]

22. Organisms live only to transfer genes to next generation...

Once they've done that "successfully"... living life is pointless from an evolutionary perspective.

[Orsino]

20. So that we stand a chance of evolving...

...to cope with the climate changes that happen much more rapidly.

[Odin2005]

23. The root systems of aspens are essentially immortal.

There is an 80 hectare clonal colony of aspen (they all share the same root system) in Utah that may be a million years old.

[Nihil]

24. Echoes of "Avatar" ...

> There is an 80 hectare clonal colony of aspen (they all share the same root system)
> in Utah that may be a million years old.

Thanks for that - I had no idea that they shared root systems like that!
:toast: