- Some human beings alive today will live to the age of
150, a prominent researcher has claimed. Steven Austad, of the University
Of Texas Health Science Center, told BBC World Service's Discovery
programme
that life span for a human being may be much longer than most people have
considered possible.
-
- And he said that he was virtually certain some children
alive now would live to the year 2150.
-
- "The evolutionary picture of the human being is
quite an interesting one, because what we've managed to do is create an
environment for ourselves that is much safer than anything we've lived
in before," he explained.
-
- "So even in the absence of medical advances, with
just evolutionary change, in the foreseeable future one would expect humans
to age at a slower and slower and slower rate."
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- Life expectancy
-
- In the industrialised world, more and more people are
living even into their 90s and 100s - and there is no sign yet of the trend
levelling off.
-
- It is this that is causing, for example, fears of pension
crises in many Western countries.
-
- But it is also evident than in some pre-industrial
societies
around the globe today, there are people who are surviving into their 70s
and 80s, despite a lack of, for example, readily available
medicines.
-
- Dr Austad's prediction relates in part to research
designed
to understand how long human beings would actually live for if left in
the natural world. Jim Carey, a biodemographer from the University of
California
at Davis, analysed the relative body and brain sizes of a range of mammals
and found that on our own, it would be likely we would die at between 30
and 40 years old.
-
- The fact that we do not is down to two factors: our brain
size and our sociality - the ability to specialise and act together.
-
- Dr Carey explained that the brain, being the instrument
of social behaviour, is the key.
-
- "We would estimate that humans would live for 30-40
years just based on size," he said.
-
- "But sociality - and more specifically brain size
- comes into this, and brain size and sociality are also related.
-
- "So when you factor in the brain size on this, then
you get an estimate of 70-90 years for the human life span."
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- Winning bet
-
- Dr Carey explained that in the natural world, it has
been observed that solitary wasps have a life span of 10 days to two weeks
- but advanced, social wasps can live for two to three years.
-
- In other advanced social groups of insects, such as
termites
and ants, the Queens can live for two or three decades.
-
- "Once you have helpers, plus a nest, the mortality
conditions and risks are a bit different," he added. "The nest
provides protection, but also with helpers, you evolve defensive behaviour.
You start specialising so that the mother can be reproductive."
-
- Similarly, lions, which live in social groups, live
longer
than tigers, which are essentially solitary.
-
- And there is very little evidence of our nomadic human
ancestors living into their 40s or 50s.
-
- "We are left with the idea of explaining why we
humans live much longer than we should for our body size," Dr Austad
said.
-
- "One reasonable guess about why that may be true
is that we live in these complex groups that provide us some protection
that we wouldn't have if we were out there on our own."
-
- Meanwhile, he added that he was so certain that someone
alive today will still be alive in 2150, he had placed a bet on it with
a friend.
-
- "It's a bet that I feel I'm so overwhelmingly likely
to win, I feel like I've stolen the money from him."
-
- © BBC MMIV
-
- http://news.bbc.co.uk/2/hi/
- science/nature/3761310.stm
|
