be rare and speciate.

S

spuriousmonkey

Banned
Banned
the most interesting story I read this week in new scientist was: The meek shall inherit the earth, provided they can survive long enough.

apparrently it is not the hugely succesful (common) species that produce the most new species. Since they are able to tolerate a wide range of conditions genetic divergence or speciation is actually more difficult. They looked at 420 marine snail species 65-85 million years old. Species that were limited in their geographic distribution gave rise to more new species. The irony is that the characteristics that make them speciate more also make them more prone to extinction. Evolution is a double edged sword it seems.

source: New scientist 1. february. 2003. page15
 
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this is actually not a new idea. large and widespread species tend to be very stable. small isolated, insular or founder populations result in amazing adaptive radiations of species. mayr's proposed idea of genomic revolutions is based on this. see, Mayr (1954), Change of genetic environment and evolution, in Huxley, Hardy and Ford (eds.) Evolution as a Process.

i've actually not read this paper myself, but Mayr discusses the theory frequently in his book, The Growth of Biological Thought.
 
rant

the idea that rare species will actually be more likely to speciate puts a new perspective on the human species. We are not really rare. We are one of the most common mammals in the world, if not the most common.

If i remember correctly human evolution occured in a period where there were many humanoid species around. More than today. This great amount of limited (rare) humanoid species evently gave rise to a few successful branches. The only remaining succesful branch is the human species. All other big apes are quite limited in their distribution and numbers (chimps, gorillas orangatan).

yes, maybe we are at the end of ape evolution. We are the last of a dying breed. Similar to horses. There used to be many horse species, but not anymore.

So we have a paradox. On one hand we are hugely succesful. We are plentiful, we dominate the world. On the other hand evolution has played a dirty trick on us. We are the last of our kind. Will the humanoids survive this all?
 
Not necessarily, spurious monkey (ha! wikked name man!)

Just because our species is unlikely to speciate does not mean that we shall not continue to evolve. In addition if the already highly fragmented populations of the world's primate species survive and stabilise in the future (over an evolutionary time period) then populations of one species are more likely to diverge from one another genetically due to the lack of genetic flow between them - i.e. due to their isolation.

However, the situation aint looking too dandy for many primate species on the conservation front, so the probability that they will persist is low. Extinction is the primary danger to speciation that the great apes now face.
 
Originally posted by filter

Just because our species is unlikely to speciate does not mean that we shall not continue to evolve. In addition if the already highly fragmented populations of the world's primate species survive and stabilise in the future (over an evolutionary time period) then populations of one species are more likely to diverge from one another genetically due to the lack of genetic flow between them - i.e. due to their isolation.

Click to expand...

hei filter, welcome to sciforums.

human society is becoming less and less isolated with every day that passes. People are migrating all over the place. There are less and less inaccessible places in the world thanks to mass transportation. Would this then prevent the creation of a new humanoid species that originates from the current human species?
 
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there's genetic evidence that early humans went through at least one extreme population bottleneck (with an Ne of about 10000).

according to the current Biological Species Concept (BSC), geographic isolation is necessary for speciation and for evolution of reprodutive isolating mechanisms. although there is some evidence in some animals species of sympatric speciation, these examples appear to be exceptions to a general rule.

H.sapiens speciation appears unlikely to ever occur given the requisite of geographic isolation. Potential possibilities; disruption of migration (unlikely unless there was some catastrophic devastation); human extraterrestrial colonization followed by preclusion of space travel (even less likely).

another aspect to consider is phenetic speciation. could humans a million years or more into the future be considered a different species. unfortunately, the current BSC is non-dimensional so that it cannot address time and space separations. So we are forced to specualte whether a reproductive isolating mechanism can evolve over time in a species that would preclude extant individuals from mating with ancestors. It's a meaningless question however.
 
Re: rant

Originally posted by spuriousmonkey
We are one of the most common mammals in the world, if not the most common.
Click to expand...

Bats and rats are ahead of us:

<i>"Bats, the world's only true flying mammals, comprise the worlds second largest mammalian species group (beaten only by the rodents) with about 950 different species worldwide, and are found everywhere except for the polar regions."</i>
http://www.stemnet.nf.ca/CITE/batsbritish.htm
 
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