Evolution happens faster in the tropics

[zandore]

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 Tuesday's issue of the journal for the Proceedings of the National Academy of Sciences, could help explain why rainforests have such rich biodiversity compared with 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 in 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.

LiveScience.com.

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One more piece of the puzzle.

[green_dude777]

Doesn't surprise me, there are secluded islands with insane amounts of diversity between species. I think Galapagos (sp?) Islands are loaded with biodiversity, I believe this is where Darwin did some of his studying.

I'm into the study of animals, and most interested in reptiles and amphibians. Adaptation happens very fast in reptiles and amphibians, so I would've assumed evolution of these animals in their prime climate happens faster than the reptiles in, let's say, Ohio.

Peace

Edited May 3, 2006 by green_dude777

[frogfish]

Very intresting...This coupled with food and temp probably is the reason for such biodiversity at the tropics...

I'm into the study of animals, and most interested in reptiles and amphibians. Adaptation happens very fast in reptiles and amphibians, so I would've assumed evolution of these animals in their prime climate happens faster than the reptiles in, let's say, Ohio

Same as I...Would love to talk with you...

I have some herp of my own...A Fijian Iguana, a male Panther Chameleon, A Ball Python, and a 14 foot Burmese (rescued from a shelter)

Edited May 3, 2006 by frogfish

[Urisk]

Oh...

Hmm, I always thought that evolution, or even natural selection, happened as a result of the need to adapt to (or indeed the process of being adapted by) a changing environment. If my understanding's correct, the Tropics are pretty constant, environmentally (at least climate-wise) and so evolution would be a waste of time, fitness and energy for an organism. In a stable environment, there is really no need to evolve, and the drive for selection will only be a result of pressure applied by, say, a predator or host organism. I dare say that arms races will be ocurring in the tropics, but then these are happening the world over as a result of predator/prey relationships... ooooh, head hurt... must get back to revision... Comparative Animal Physiology

RKD

[robbieb]

the reason for the constant changing roadkill goes into survival of the fitess. meaning two types of insects(this is mostly insects doing these its takes a larger time for larger animals to evolve) both eat another type of insect now the one capable of chasing down and killing the insect better will evole now the other species must either evolove to fit this new situation of its main prey no longer being availbe or die. another example would be one type of insect hunts another type now say within that group of insects one uses speed to hunt down its prey and the other uses stealth eventualy they wiull split one will use stealth and the other speed and sson they will becom diffrent species. and another is lets say a snake that hunts amphibians its uses a hemo toxin to kill its prey(a toxin that affects the animals blood) now eventualy those of the amphibians species that are more resistan to the tocxin will survive. thne eventualy the snake needs to develope a more potent toxin other wise its prey will no longer be affected by the snakes bite to do this the snakes with more potent toxin will survive while those that have weaker ones will starve and die thus the gene for potent toxin will get passed on. theres so many examples i could list but these are good for now i tihnk. now because there are more habitats within a rainforest between the diffrent levels of tree' and tree tops earth rivers lakes waterfalls caves and such more animals are present to fil lthe nichees in each one now when u have more animal together more evolution will go on

Edited May 4, 2006 by robbieb