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Old 09-24-2010, 03:42 PM   #1
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Default Early Warning Signs Could Show When Extinction Is Coming

Early Warning Signs Could Show When Extinction Is Coming
By Brandon Keim at Wired.com
Thu Sep 9, 2010 8:00pm EDT

Early Warning Signs Could Show When Extinction Is Coming | Reuters
excerpt from above:
Animal populations headed for extinction may give the same signals seen before crashes in coral reefs, the Sahara’s climate and even stock markets.

These systems are very different, but each exhibits what’s known as “critical slowing down,” in which a loss of resilience magnifies the effect of small perturbations, which become more and more difficult to recover from.

“Critical slowing down is an early warning signal. If you can detect it, you can know that you’re headed for a tipping point,” said University of Georgia ecologist John Drake...
The tendency of man's nature to good is like the tendency of water to flow downwards.
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Old 09-26-2010, 08:41 AM   #2
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In any animal population, the number of individuals oscillates naturally. A few extra offspring are born, putting a strain on resources; that leads to a few extra deaths or a drop in births, which frees up resources that allow the population to grow again. These fluctuations converge on an equilibrium somewhere in the middle. Both the control and nutrient-deprived populations followed this pattern.
I remember the concept of "population stress" from the primate studies back in the 60s-70s. There is an increase in reproduction to compensate for increased mortality.
In some populations there is extreme sexual dimorphism such that females are much smaller than males and there may be many more of them. The social effects of this are that groups containing 1 male and several females develop.

Other reproductive changes can occur such as the earlier onset of estrus or menses in humans -- thus each female has a greater lifespan of productivity.

Some anthropologists have suggested that these extreme conditions of population stress led to the development of early hominids. Evolution would be an alternative to extinction. A population in equilibrium with its environment on the other hand would not be under stress and would be less likely to evolve. Reproduction would be stable in an environment of plentiful resources.
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