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Author Topic:   Evolution Occurs Faster at the Equator
melatonin
Member (Idle past 6209 days)
Posts: 126
From: Cymru
Joined: 02-13-2006


Message 1 of 18 (308317)
05-01-2006 8:19 PM


Evolution Occurs Faster at the Equator
By Ker Than
LiveScience Staff Writer
posted: 01 May 2006
05:00 pm ET
Plants and animals living in warm, tropical climates evolve faster than those living in more temperate zones, a new study suggests.
The finding, detailed in the May 2 issue of the journal for the Proceedings of the National Academy of Sciences, could help explain why rainforests have such rich biodiversity compared to other parts of the planet.
A census of all the plants and animals around the world would reveal that species richness is uneven: it is highest in the tropics, the regions of Earth near the equator, and lower the closer one goes toward the planet's poles.
What's going on
To investigate the reasons for this trend, Shane Wright of the University of Auckland, New Zealand, and colleagues looked at the rate of molecular evolution for 45 tropical plants and compared it to that of related species living at more temperate latitudes.
The researchers examined the rate at which DNA bases in the plants' genetic code are substituted. Like characters in a four-letter alphabet, bases are DNA molecules arranged to spell out instructions for building proteins. If one of the letters”A, T, G or C”become substituted with another, the instructions can change and a dysfunctional or entirely new and useful protein can be produced.
The researchers found that tropical plants had more than twice the rate of base substitution compared to their temperate cousins.
How it works
The finding supports a theory put forth by biologist Klaus Rohde in 1992 that climate can have a powerful effect on how fast organisms evolve and branch off into new species. Scientists think it works like this:
Warmer temperatures speed up metabolism by allowing chemical reactions to occur at a faster rate, but this increased efficiency comes at a price: it produces higher quantities of charged atoms or molecules called "free radicals," which can damage proteins”including DNA. Higher metabolism also speeds up DNA replication, which is just another chemical reaction, and this can increase the number of copying mistakes that can occur.
Together, damage to DNA by free radicals and replication mistakes could result in mutations that, over time and through natural selection pressures, can form new species.
Evolution Occurs Faster at the Equator | Live Science

Replies to this message:
 Message 4 by macaroniandcheese, posted 05-04-2006 4:48 PM melatonin has replied
 Message 6 by Quetzal, posted 05-04-2006 5:07 PM melatonin has not replied
 Message 7 by Quetzal, posted 05-04-2006 6:07 PM melatonin has not replied

  
melatonin
Member (Idle past 6209 days)
Posts: 126
From: Cymru
Joined: 02-13-2006


Message 8 of 18 (309170)
05-04-2006 6:14 PM
Reply to: Message 4 by macaroniandcheese
05-04-2006 4:48 PM


Article Preview
How chemicals can speed up evolution
06 May 2006
Andy Coghlan
Magazine issue 2550
The mystery of how human DNA evolves during someone's lifetime looks a step closer to being solved
Researchers in Japan have found evidence that environmental agents that cause chemical changes to our DNA throughout life may increase the amount of shuffling and mutation that occurs within our DNA during the formation of egg and sperm cells. So exposure of our DNA to reactive chemicals may actually drive evolution by promoting genetic diversity in our children.
Yusaku Nakabeppu and his colleagues at Kyushu University in Fukuoka have shown that, if unrepaired by enzymes, a type of chemical damage called oxidation can reshuffle DNA's four basic building blocks - adenine, thymine, cytosine and guanine.
Normally, cytosine always pairs with guanine, and adenine with thymine, but unrepaired oxidation can disrupt these pairings, so that when a cell multiplies, the DNA sequence handed down to "daughter" cells is subtly altered...
http://www.newscientist.com/channel/life/mg19025504.600.html
It is possible that oxidative damage from environmental agents may speed up evolution. So, maybe anti-oxidants do slow evolution.
....
Hi Quetzal,
I guess it's just one hypothesis as to why these areas have greater diversity than more temperate regions. Just thought it was interesting.
And I'm quite envious of the fantastic location you find yourself in. I love south america. I'm sure it beats the view of Snowdon I have here in wales.

This message is a reply to:
 Message 4 by macaroniandcheese, posted 05-04-2006 4:48 PM macaroniandcheese has not replied

Replies to this message:
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