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I saw a presentation from an evolutionary biologist who may the point that we die because there is no evolutionary pressure not to die. Once we've birthed and
by abruzzi 14y ago
I saw a presentation from an evolutionary biologist who may the point that we die because there is no evolutionary pressure not to die. Once we've birthed and raised out young, we are no longer relevant from an evolutionary perspective. He tested this with fruit flies by separating the young by gender for increasingly longer periods of time effectively delaying breeding so only the longer lived specimens could live to breed. By doing that over many generations, I believe he tripled the life expectancy of his test group.
- adrianbg 14y agoIf you live longer you can have more offspring. Maybe constraints on your time and resources for raising offspring are really what prevent longevity from being much of an advantage?
- saraid216 14y ago> If you live longer you can have more offspring. I'm pretty sure this is untrue; the likelihood of offspring drops pretty precipitously after certain ages.
- jere 14y ago>the likelihood of offspring drops pretty precipitously after certain ages. That's a bit of circular logic though. We can't explain why we age (and thus die) by pointing out that we age (and thus are less able to reproduce).
- adrianbg 14y agoRight. The relevant metric is how long you remain fertile, not how long you live.
- adrianm 14y agoSounds like an interesting experiment to read about. Do you remember the biologist's name?
- pathdependent 14y agoWould you happen to have a link? I've been interested in toying around with this idea (just for fun) for a while, but I haven't started doing the actual research. My instinct would be that (biological) immortality is (mostly) non-existant not only because there is no evolutionary pressure not to die, but because there is evolutionary pressure to die after begetting offspring. Very long lived progenitors would homogenize the gene pool, if not by incest then by sheer number of offspring. This would make them fragile in the face of both genetic errors and environmental shifts. To counter this fragility, child birth might be infrequent. However, if child birth is infrequent, there is an increased probability of death before child birth.
- lincolnq 14y agoNo, that's group selection. If a progenitor could live a very long time and continue to produce offspring, it might be worse for the species, but it would be so much massively better for the individual's genes that those would be passed on.
- philwelch 14y agoYou don't have to go into biology to explain why we die; the physics is sufficient. Everything is subject to entropy.
- gloryless 14y agoClosed systems. Entropy is a hard to defend answer.
- jlgreco 14y agoThere are plenty of examples of (admitted, simpler than humans) organisms which are effectively "immortal". The heat death of the universe will get them all, but human mortality is nevertheless a good deal more complicated than just entropy.
- philwelch 14y agoRight, so the question is why we die when we die, not why we die at all.
- xhroot 14y agoIn The Selfish Gene, Dawkins proposed that grandparents - obviously well beyond child bearing - can affect their gene propagation by caring for their grandchildren, at least indirectly. What a true scientist; most people are content to think we dote on grandchildren as a civilized people with innate appreciation for new life. Rather, our genes will eradicate those who fail to help their offspring's offspring survive. http://musingsofscience.wordpress.com/2010/07/21/book-review-the-selfish-gene-by-richard-dawkins/ http://musingsofscience.wordpress.com/2010/07/21/book-review...