>> That advantage is increased diversity within a species.
Actually evolution doesn't really work like that. Traits will rarely evolve to the benefit of a species. Evolution operates much more strongly at the individual level & even more strongly at the gene level.
It's discussed some place in the video belos but I don't remember which part (of 6). Worth watching if you're interested anyway. Otherwise, the evolutionary reason given there for aging is an evolutionary bias for 'fixing' diseases that affect the young. A disease, deadly at 5 years old is more of a problem for lifetime reproductions then something deadly at 20 which is more of a problem then something at 30 etc. I'm not sure if this explains aging in it's entirety, but it seems like a logical part.
None of your ancestors died at infancy. Very few are likely to have died younger then 15. You can probably trace some that died younger then 25. It would be unusual not to have some within memory that died younger then 50.
Since ancestral humans probably rarely lived (reproduced or contributed to the reproduction of their offspring) past 40-50, it's not surprising that there are many issues unique to this life stage that have had very little evolutionary tweaking done.
What I would like to ask/say (Richard, if you're reading, speak up) is that this might explain why old age illnesses are more severe. It doesn't do much to explain the discrepancies in young/old illnesses.
Actually evolution doesn't really work like that. Traits will rarely evolve to the benefit of a species. Evolution operates much more strongly at the individual level & even more strongly at the gene level.
It's discussed some place in the video belos but I don't remember which part (of 6). Worth watching if you're interested anyway. Otherwise, the evolutionary reason given there for aging is an evolutionary bias for 'fixing' diseases that affect the young. A disease, deadly at 5 years old is more of a problem for lifetime reproductions then something deadly at 20 which is more of a problem then something at 30 etc. I'm not sure if this explains aging in it's entirety, but it seems like a logical part.
None of your ancestors died at infancy. Very few are likely to have died younger then 15. You can probably trace some that died younger then 25. It would be unusual not to have some within memory that died younger then 50.
Since ancestral humans probably rarely lived (reproduced or contributed to the reproduction of their offspring) past 40-50, it's not surprising that there are many issues unique to this life stage that have had very little evolutionary tweaking done.
What I would like to ask/say (Richard, if you're reading, speak up) is that this might explain why old age illnesses are more severe. It doesn't do much to explain the discrepancies in young/old illnesses.
http://www.youtube.com/watch?v=pcnCJqDa1us