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

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

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

the more more maintenance needed?

Literally. We burn fuel to sustain chemical processes.

"Like" button as on Facebook?

We also rust.

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.

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.

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.

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.

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

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.

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?

...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.

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. :)

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?

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.

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.

there are also immortal fungi and cancer cells.

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.

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.

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

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

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

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

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.

> 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!
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