Comments on: Nature’s Stinginess

By: michael

michael — Sat, 17 Jan 2009 01:26:26 +0000

Thanks Robin, will edit the link

By: Robin Z

Robin Z — Fri, 16 Jan 2009 17:05:53 +0000

Thanks for the post – I was looking for a reference on the elephant thing, and I came upon it.

(P.S. the Carlin sketch link is down – here’s another copy.)

By: Sex, what is it good for? « It’s Alive!!

Sex, what is it good for? « It’s Alive!! — Tue, 28 Oct 2008 13:32:39 +0000

[...] All a sexual reproducing species has to do is be suave enough to get someone up the duff**. After that you can run away and die. Everything after the “act” is generally no consequence. Incidentally, that’s why elephants starve to death in old age (which we’ve already covered). [...]

By: Nature doesn’t care about you « It’s Alive!!

Nature doesn’t care about you « It’s Alive!! — Thu, 09 Oct 2008 12:24:19 +0000

[...] Perhaps a certain biologist going all silly billies should brush on his basic evolutions. [...]

By: zayzayem

zayzayem — Thu, 09 Oct 2008 12:18:15 +0000

“But we probably also have get-cancer-genes, which is why we get cancer in old age.”

They are called oncogenes.

By: michael

michael — Tue, 16 Sep 2008 21:51:32 +0000

Divalent — you might be right on the elephants, however it would also depend on a few other factors. For instance, if 100 grandchildren were alive there might only be 4 or 5 grandparents alive by then (the others dying previously for various reasons) — combined with the fact that older organisms consume less and are slower to find food etc, the math might work out to say that there isn’t sufficient advantage to the grandchildren to provide selection pressure for stopping at 6 sets of teeth. But yes, they could have been selected for.

DDeden — not sure what you mean — isn’t the fact that sleep can be conceptualised as anti-photosynthesis just a coincidence? (Since photosynthesis evolved independantly of animals and sleep)

By: divalent

divalent — Tue, 16 Sep 2008 13:25:16 +0000

NS theoretically can operate on some gene/traits that manifest themselves long after the reproductive years, and so it is not necessarily correct to say that traits in such individuals are invisible to NS.

For example, it probably would be beneficial to the survival of an elephant’s grandchildren (who share some genes) that they stop consuming precious local resourses. So it’s not inconceivable that there might be selection pressure *against* the development of a 6th set of teeth, and *for* the development of late-onset fatal diseases.

By: DDeden

DDeden — Tue, 16 Sep 2008 00:54:58 +0000

Why do we (animals) sleep? Sleep is an anti- photosynthetic period. Green plants respire all the time, but photosynthesize only in sunlight, animals respire all the time, but sleep only (largely) in anti-sunlight (darkness).

By: michael

michael — Sun, 24 Aug 2008 09:11:53 +0000

Hi Shul, thanks for commenting. We might know of some reasons why we sleep but the popular media tends to paint it as a big mystery. We do have sleep patterns quite different to similar animals so I reckon there are still unanswered questions. As for aging do you think at least SOME of the effects could be due to genes that weren't selected for but have still snuck in to our genome? (It seems there's a lot of useless code floating around the human genome, even amongst the DNA sequences that code for proteins)

By: Shul Candyman

Shul Candyman — Sat, 23 Aug 2008 19:10:53 +0000

So… I’m a molecular biologist… a few thoughts:

nature never optimises for the sake of an organism. It’s just too stingy.

Lazy’s more like it. As long as it works, there’s no need to optimize. Whatever works. Whatever survives.

we still don’t know why we sleep.

Really? Haven’t read up on sleep much. I think it’s obviously a device to slow down the body on a regular basis to heal and grow.

At that age elephants no longer reproduce and are hence invisible to natural selection.

Did not know about the elephants. Interesting.

There’s an old mystery, why do we age? Many people believe that aging is not determined by specific genes. Since aging is a phenomenon that occurs primarily after the age of reproduction, there does not appear to be any driving evolutionary selective force for genes that actively promote aging.

However, it remains possible that aging is a byproduct of genes that are necessary before reproduction.