Uncle Davey wrote:
>
>>In article <ILdDb.6301$Oh1.248@twister.socal.rr.com>, news@jcsm.org
>>wrote...
>>
>>>Boikat wrote:
>>>
>>>>"Dr. Jason Gastrich" <news@jcsm.org> wrote in message
>>>>news:<wjWCb.16355$HL2.14048@twister.socal.rr.com>...
>>>>
>>>>>Seppo Pietikainen wrote:
>>
>>[snip]
>>
>>
>>>>>Bait and switch? Saying that micro-evolution happened,
>>
>>Not just happened, happens. It's readily observed.
>>
>>so
>>
>>>>>macro-evolution must have happened is a bait and switch. It's
>>>>>illogical.
>>
>>"Macroevolution" as it's defined by scientists
>>
>>http://www.talkorigins.org/faqs/macroevolution.html
>>http://www.nhm.ac.uk/hosted_sites/paleonet/paleo21/mevolution.html
>>
>>is also observed to occur [observed speciations],
>>
>>http://www.talkorigins.org/faqs/faq-speciation.html
>>http://www.talkorigins.org/faqs/speciation.html
>>http://www.talkorigins.org/faqs/evolution-research.html
>>
>>and there's plenty of strong evidence that it has occurred
>>throughout the billions of years life has existed on earth.
>>
>>http://www.talkorigins.org/faqs/comdesc/
>>http://www.talkorigins.org/faqs/faq-transitional.html
>>http://tolweb.org/tree?group=life
>>http://www.ucmp.berkeley.edu/historyoflife/histoflife.html
>>http://www.ucmp.berkeley.edu/alllife/threedomains.html
>>http://www.ucmp.berkeley.edu/alllife/eukaryotasy.html
>>
>>
>>>>What prevents an accumilation of "micro-evolution" from becomming
>>>>"macro-evolution"? Where do you draw the line, and why?
>>
>>Biologists of course draw the micro/macro line at speciation. It's
>>observed to occur, so we should all agree that at least _some_
>>"macroevolution" does happen. The question then becomes one of
>>whether there are limits to macroevolution, or if your prefer,
>>limits to the common descent of life on earth. Are there separate
>>"kinds" unrelated by descent to other such "kinds", or is all life
>>on earth related by descent from common ancestors? Biologists
>>agree that the evidence strongly indicates the latter.
>>
>>I don't see that larger-scale macroevolution requires any new
>>phenomena than those which we do observe happening today: accumulated
>>microevolution, plus speciations, plus extinctions, resulting in a
>>nested hierarchy of groups within groups within groups.
>>
>>What else would be needed? [There are those who argue for the
>>existence of larger scale, macroevolutionary phenomena such as
>>"species selection", but IMO that clearly reduces to the
>>cumulative effects of speciations and extinctions.]
>>
>>
>>>Here is a better question. Why do you believe that there is no line?
>>
>>When
>>
>>>we have found clear limits to the evolution we have observed,
>>
>>Where have we found any such clear limits? What causes the limits? Are
>>there any actual mechanisms to prevent [much] macroevolution from
>>occurring, or is it all just a matter of insufficient time [I often
>>point out that YECs really don't need to postulate any evolution-
>>limiting mechanisms, since they believe the world is far too young for
>>much evolution to have occurred]?
>>
>>
>>>why would you
>>>estimate that there could be no limits?
>>
>>Why argue for limits? What prevents the accumulation of changes, or
>>again is it just that you believe the world is too recently created?
>>
>>If this is to become a discussion of specially-created "kinds" and
>>their limits, I'd ask: how can the "kinds" and their boundaries be
>>recognized, just by studying the organisms? How can we all tell if
>>two organisms are in the same or in different kinds? Creationists
>>generally seem unable or unwilling to give clear objective criteria
>>for "kind" recognition. The few who do try often seem wildly
>>inconsistent.
>>
>>[snip]
>>
>>cheers
>>
>
>
> I think it is very hard to know what a kind is, sometimes.
>
> Here's my understanding of it, which you are welcome to challenge:
>
> It says that they were made after their kind, and that they reproduce after
> their kind.
>
> Now on the surface, that would suggest that a kind could have a definition
> of animals and plants which are capable of interbreeding, and producing
> fertile offspring in the F1 generation.
>
> However, we know that over time either man-driven selection or natural
> selection makes distinctions within the kind, so that they are no longer
> physically able to reproduce, such as populations of Anableps with left
> handed gonopodiums and right handed gonopodiums with their respective
> females cannot interbreed physically any more, and I understand there is
> also a fruit fly, and probably a bunch of other examples in Insecta and
> Mollusca which bear this out. They were in my view one kind, but they have
> become unable to interbreed. In this case some say we have speciation,
> others wouldn't call this speciation. Scientists also have more than one
> view so we're not the only ones to have more than one view. If you could
> imagine a male chihuahua and a female great dane - they're both dogs, Canis
> domesticus, but you couldn't really interbreed them without artificial
> insemination. This way round the poor chap can't reach, and the other way
> round and the female chihiahua would get a doggy hernia from the experience
> or something like that.
>
> Similar things are happening at DNA code level to reflect the morphological
> specification, and maybe I could envisage things happening in the code
> without a morphological reflection. That seemed to be one of the things John
> Harshman was saying to me in our conversation yesterday. So then we would
> have total speciation. Are these kinds? Not when that happens, they cannot
> be kinds. They are simply degenerations of the original kind that have
> become mutually exclusive, in my view, because that would go beyond the
> definition of kinds that the kinds were established at creation.
> Nevertheless, within the six, seven, eight, nine thousand years of physical
> history, as opposed to the notional history of the mature creation, quite a
> few cases of this speciation could occur within one kind. Then you get a
> galapagos finch scenario, or maybe a Corydoras scenario.
>
> Corydoras has about 150 species and subspecies, and the genus has all manner
> of interesting biological oddities, such as mimicry, symbiosis, etc,
> appearing among its ranks.
> It is one of the most common genera of fish over the whole of Amazonia and
> covers also the bulk of south America. Its armoured plates make it the ideal
> subject for fossilisation. How many fossilised species are there?
>
> One.
> http://www.scotcat.com/articles/article49.htm
>
> Corydoras revelatus. It is the only Cory fossil in existence, and yet it is
> an almost perfect fossil. Why are there no more?
>
> (Incidentally, I was standing next to Steve Pritchard and David Sands when
> Steve took this picture, being, as I was, a fanatical ichthyologist at the
> age of 14. It was on a course that the University of London did for people
> who wanted to learn Ichthyology in conjunction with the Natural History
> Museum. When the University of London discovered I was too young to be on
> the course, they tried to chuck me off it. They thought they would get into
> trouble letting a school kid come up to London every Thursday to be on one
> of their courses. But the Museum weren't hearing any of it, and said if I
> wanted to take part, they, the University had to let me. How about that? )
>
> Probably at the time of the flood there was only Corydoras revelatus. The
> whole of the 155 separately defined species are probably one single kind. Do
> they interbreed? No they don't, not most of them. They're tricky enough to
> breed within the species, most of them. I've never done it, although I have
> bred other armoured catfishes, like Hoplosternum (now Megalichthys) and
> Ancistrus, which I've got going at the moment.
>
> So, for me, the best definition of a kind, true to both what I have been
> priviledged to observe of nature as well as in the Word of God, would be
> "the whole population of descendents of a group of animals or plants which,
> at the time of their creation, were able to breed and have offspring that
> were fertile."
>
> I do not regard the fact that you can clone and at the same time splice
> genetic material from completely different animals into genes as being in
> any way relevant to what constitutes a kind, I might also add.
>
> Now you can shoot all of that down in flames. I know there's as much
> philosophy there as what you might call science, but that's just the sort of
> guy I am.
>
> Uncle Davey
>
While not being close to *anywhere* being happy with, I'd propose a couple of
yuletide books, well, maybe just one:
The Map That Changed the World: William Smith and the Birth of Modern Geology
ISBN: 0060931809
You'll find it extremely informative.
Seppo P.
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