Thursday, 18 May 2006

More heat, more species. Why?

Research by three Auckland scientists has answered an old ecological mystery: why is it that the farther from the tropics you travel, the fewer species there are.

Why does the 'nicer' climate produce more species?

The answer provided by the scientists' research and summarised by The Economist is simple (ie., not irreducibly complex):
That there is more sunlight—and so more opportunity for photosynthesis—at the tropics explains why warm climates create more living matter (or biomass, as it is known to ecologists). It does not, however, explain why this biomass is apportioned into more species... By a process of elimination ... the three researchers were left with the conclusion that, by pushing metabolic rates up, tropical heat causes more mutation and thus more speciation. In other words, evolution happens at a faster rate in Kenya than, say, in Kansas. It does, though, occur in Kansas, too—whatever some of its citizens might think.
Read the full piece here. And the abstract for the published research here.

LINKS: A heated debate: A clue to an old ecological mystery - (stolen from) The Economist
print edition
The road from Santa Rosalia: A faster tempo of evolution in tropical climates - Shane Wright, Jeannette Keeling, and Len Gillman, Proc. Natl. Acad. Sci. USA

TAGS: Science, Conservation, Global_Warming, Religion


  1. Eh, should the first paragraph not be "the less species there are"?

    By the way, speciation is a real confirmed phenomon. Unfortunately it involves only reshuffling of existing genetic material. All the dogs we see around us are descendants from a single dog, no debate there.

    By breeding you can create all kinds of dogs.

    But when someone asks us to believe that frogs evolved into dogs, I'm asking for a bit more proof.

    By the way, the trick doesn't happen for rats. Unlike dogs pet rats don't come in great variety and attempts to increase it haven't succeeded

  2. Misrepresenting once again :-)

    No one is saying that frogs evolved into dogs. They are saying that frogs and dogs have a common ancestor.

    Dogs have speciated slightly. All the different types of dogs have been derived from wolves in the last 7000 years - a remarkably short time to generate everything from poodles to rottweilers.

    The common ancestor of frogs and dogs (and in fact all tetrapods) lived more like 340 million years ago. Plenty of time to get a bit more variation in - frogs, lizards, birds, rabbits, humans...

    If it's easy to accept that a poodle and a rottweiler have the same great-great-etc-grandparents, why isn't it almost as easy to see that all the tetrapods have the same great-(x 175 million)-grandparents? They're all made of similar materials and have the same basic body plan.

  3. Berend, I just know you're going to love this... :)

    Human Ancestors May Have Interbred With Chimpanzees

    When the ancestors of human beings and the ancestors of chimpanzees parted ways 6.3 million years ago, it was probably a very long goodbye. Some of their descendants may even have gone back for a final tryst.

  4. Speciation can get quite complicated. It's possible to transfer genes between two populations that can't interbreed if there are intermediates who can breed with both. (See this ring species article for a quick summary.)

  5. It seems to work the opposite at sea. As a seafarer I noticed without too much trouble that the tropics though pleasant were like a desert for birdlife. The closer you got to the poles though the greater the life. A trip down to the ice or near it is an opportunity that nobody should miss if it's offered.

  6. Here is some more interesting news, very recent...

    Ready, set, mutate... and may the best microbe win

    Even with modern genomic tools, it's a daunting task to find a smoking gun for Darwinian evolution. The problem lies in being able to say not just when and how a specific gene mutated but also how that one genetic change translated into real-world dominance of one population over another.

    Rice University biologists, using an ingenious experiment that forced bacteria to compete in a head-to-head contest for evolutionary dominance, today offer the first glimpse of how individual genetic-level adaptations play out as Darwinian natural selection in large populations. The results appear in the May 19 issue of Molecular Cell.

    "One of our most surprising findings is that an estimated 20 million point mutations gave rise to just six populations that were capable of vying for dominance," said lead researcher Yousif Shamoo, associate professor of biochemistry and cell biology. "This suggests that very few molecular pathways are available for a specific molecular response, and it points to the intriguing possibility of developing a system to predict the specific mutations that pathogens will use in order to become resistant to antibiotics."

  7. julian, on the first story, did you note that "maybe". One was the last time Newton said that maybe an object in motion needs a counter-force to stop? Evolution, anything goes.

    2nd link: very interesting. But note it's about existing genes, reshuffling of existing functionality. The experiment run without the metabolic protein wouldn't give rise to a mutation which creates it is my prediction.

  8. bernard, if you see two cars, a mini and a mercedes, they obviously have some similarities. They share some design characteristics. Does that mean the one evolved into the other?

    This kind of reasoning looks to me like arguments used in the alchemist era to explain things.

    And on speciation: did you know that creationists need very rapid speciation? The arguments is as follows: when Noah came out of the Ark 4000 years ago, he didn't take every breed of wolve and dog. He took just one, some kind of ancestor (m-dna research gives some credibility to this idea). But obviously we have a lot of wolve and dog species know, so all this must have happened in less than 4000 years, even less than the 7000 you mentioned. So I guess that Creationists love confirmation for rapid speciation.

  9. When I see a Mini and a Mercedes and note their similarities I assume that they have a common heritage. Since I also observe that they don't reproduce, I assume that the information used to build them is held in their creators' minds.

    The fact that designed objects are designed is not in dispute. Since the key thing we're talking about is self-replication, how exact the replication is, and whether changes can accumulate over time, why do you persist in fogging the conversation with discussion of things that you know don't reproduce. You're comparing apples with oranges - and they haven't been the same thing for 65 million years :-)


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