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Author Topic: Self destructive evolution?  (Read 2317 times)

Offline Europan Ocean

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Self destructive evolution?
« on: 02/09/2013 07:30:56 »
In evolution on the earth, there is no evidence of self destructive evolution is there? Only man devised plastic, which with bones is a carbon compound that does not readily decay. If early life produces plastic instead of protein or cellulose membranes, life on earth would have hit a stumbling block, as the seas would have filled with non decaying plastic. I expect the seas were once thick green with algae, giving of helpful oxygen which other life forms later used. But if it gave off chlorine, Cyanide or left plastic shells that would float and clog and not decay for long times, life would have ended itself in by products.

Alternately life could have metabolized water by nature, leaving less and less behind, until like CO2 there was none left almost at all.

Also life could have consumed itself rather than balancing out into an ecosystem.

This could have happened on other planets. Why not here on Earth?


 

Online alancalverd

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Re: Self destructive evolution?
« Reply #1 on: 02/09/2013 07:49:50 »
Living things are generally selfdestructive but rely on other living things to fix the problem.

If plants grew with no animals, there would eventually be no carbon dioxide in the atmosphere to sustain further plant growth, and vice versa. Yeast eventually poisons itself with alcohol unless Man comes along with fresh grapes and removes the excreta. And Man would drown in his own feces if it wasn't for the friendly bugs down at the sewage farm.

I guess quite a few species ate and reproduced themselves into a corner where one crop failure extinguished the lot. It's only Man's mobility and adaptability that stops it happening to us, and there have been quite a few near misses.
« Last Edit: 02/09/2013 07:52:31 by alancalverd »
 

Offline CliffordK

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Re: Self destructive evolution?
« Reply #2 on: 02/09/2013 08:32:37 »
Most estimates indicate that there are more species that have gone extinct than are alive today.  I don't know if that includes species that had a clear evolutionary pathway to species that are alive today, but there have been many evolutionary dead ends. 

Consider the Tasmanian Devil at serious risk of extinction due to a communicable cancer combined with their ill temperament.

Earth is the only planet that we have ever identified as supporting "life".  Different estimates indicate that there may be a great many earth-like planets.  However, it is quite possible that for every planet that succeeds, a billion fail.  We just happen to be on a planet that took a successful evolutionary pathway in which humanity evolved.  We would never have existed on the "failed" planets.

Life destroying water?  Obviously water is an integral part of the carbon cycle.  On an arid planet, it could be a scarce resource, and breaking down carbon dioxide + water to produce hydrocarbons, one could loose the water.  Fortunately it is in an excess here.  Or, perhaps it could be broken down to 2H2+O2, and the excess hydrogen might escape the atmosphere.

Another potential calamity.  Reduced Nitrogen (ammonia and ammonia products) is vital for all life on Earth.  As farmers have discovered, supplying more reduced nitrogen greatly improves crops.  So, why can so few organisms effectively convert N2 to NH4+?  If the process was to proceed uncontrolled, could Earth loose its whole atmosphere?  Has it happened elsewhere?

Again, we can assume the basic building blocks for earth-like planets are common, relatively speaking, in the universe.  Yet, by looking at Earth alone, we are unable to determine the success rate of life transforming the planets until hominid-like species evolve.
 

Offline evan_au

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Re: Self destructive evolution?
« Reply #3 on: 02/09/2013 12:09:16 »
Scientists studying ancient rocks suggest two ways that microscopic life on Earth may have almost destroyed itself:
  • Ancient plants turned Earth's atmosphere (thought to have considerable carbon dioxide) into oxygen. For anaerobic microbes, oxygen is a vicious poison, so these plants nearly poisoned everything.
  • The carbon dioxide in the atmosphere kept the atmosphere warm. Some think that the loss of carbon dioxide may have triggered Earth turning into a giant snowball.
 

Offline CliffordK

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Re: Self destructive evolution?
« Reply #4 on: 02/09/2013 18:42:38 »
There are also theories that the sun has been getting warmer over time.  The earth's core has also been slowly cooling. 

It is also possible that plants sucking up carbon dioxide has helped stabilize Earth's temperature and prevented the planet from overheating.  Perhaps there is a feedback mechanism that too little atmospheric CO2, and the planet cools and slows the growth of the plants until the solar heating can compensate.
 

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Re: Self destructive evolution?
« Reply #4 on: 02/09/2013 18:42:38 »

 

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