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bunbury
Post  Post subject: Missing links  |  Posted: Fri Nov 15, 2013 10:33 pm
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This had never really occurred to me before I read a chapter in Dawkins’ The Greatest Show on Earth.

The naming of fossils in the human line of descent inadvertently provides fuel for the evolution-deniers’ confused beliefs. One fossil is classified in the genus Australopithecus and another more recent find is classified as Homo but both are in our direct line of descent. To an evolution denier there is no evidence that we are descended from either of these because the link between Australopithecus and Homo is missing and the link between, say, Homo ergaster and Homo sapiens is also missing. No species is classified as intermediate, therefore to the denier there are no intermediates.

The reality, as Dawkins points out, is that even a perfect intermediate would still have to be shoehorned into either Homo or Australopithecus, just because of zoological naming conventions. Dawkins likens this to the necessary but arbitrary convention of declaring a person to be an adult at the age of eighteen. “Nobody seriously believes there are two kinds of people, children and adults, with no intermediates. Obviously we all understand that the whole period of growing up is one long exercise in intermediacy.”

Apparently the naming of fossils is a highly contentious exercise in which rival paleontologists sometimes get into bitter arguments. Perhaps a better system is needed, in which the line of descent and the relative age are indicated somehow alphanumerically.


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marnixR
Post  Post subject: Re: Missing links  |  Posted: Sat Nov 16, 2013 2:24 pm
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it's only a creationist ploy to insist that whatever fossil is found is either one thing or another
they do the same thing with e.g. Archeopteryx - because it has feathers it's a bird to them
and they totally ignore all the bona fide dinosaurs that have now been found to have feathers or proto-feathes

true that classification tends to compartmentalise, but that usually is ok because species tend to be rather separate in life and in fossils, but there will always be the cases where it's not totally clear where to lump it

to scientists that's not a problem since they're aware that's how life is - however, to creationists if it doesn't fit the black-and-white picture they have in their head, it must somehow be forced into it

i think the problem is less with the the way we allocate species names and more with how some people can't handle shades of grey

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bunbury
Post  Post subject: Re: Missing links  |  Posted: Sat Nov 16, 2013 4:42 pm
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Quote:
species tend to be rather separate in life and in fossils


Species in life today are separate but there was never an occurrence of a Homo ergaster mother giving birth to a Homo sapiens child. Every mother who ever existed only gave birth to a child of the same species so if we did happen to have a complete fossil record the positioning of the name change from one species to another would be completely arbitrary. Some people do look at the shades of grey and say you've got this light grey and this dark grey and nothing in between so you've got no evidence that the dark grey evolved from the light grey. I think this is a problem for paleontologists if they want to convince these people of the fact of evolution, which they currently reject.


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marnixR
Post  Post subject: Re: Missing links  |  Posted: Sat Nov 16, 2013 10:03 pm
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obviously every parent gives birth to a member of her own species - it's the gradual change over time that means that after thousands or millions of years members of the same lineage are no longer the same species

think ring species in time rather than in space - the classic ring species is the herring gull assemblage : there's about four subspecies where each adjacent subspecies can still interbreed with the subspecies nextdoor
except for when the ring was completed by migration from the americas to europe across the north atlantic, the 2 ends of the ring species no longer can interbreed, hence are separate species - but here's the crucial bit : at no point going east from north-western europe is there a hiatus but an interbreeding continuum

so with that logic where do you define the new species ? it's the same with breeding lineages over time : adjacent generations can interbreed, but if you had a time machine and brought members of the same lineage but separated by, say 1 million years, chances are that they would no longer be able to interbreed

in essence you shouldn't take the opposite view of the black-and-white picture either : just because there's a continuum of greys doesn't mean that there's no such thing as black and white, or that if forced to split a continuum in separate categories there's not such a thing as an artificial boundary, even if the changes in the continuum are real enough

Richard Dawkins explained this topic well enough in The Tyranny of the Discontinuous Mind

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bunbury
Post  Post subject: Re: Missing links  |  Posted: Sat Nov 16, 2013 11:08 pm
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I don't disagree with anything you say. I'm just saying that the nomenclature gives evolution deniers an excuse not to think any deeper, and maybe a different nomenclature would help them see the light.

Nah, probably not.


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marnixR
Post  Post subject: Re: Missing links  |  Posted: Sun Nov 17, 2013 8:45 pm
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i'm afraid when you talk to creationists you just can't win, whether the nomenclature gives them reason to find fault or not - they're so good at filtering out anything that doesn't fit and then put it through their own reality distorter that whatever you say they'll either find reason to say it's broken, or they'll part-quote what you said in such a way that they make it appear that you said something totally opposite to what you actually meant

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