From: asiivo@cs.joensuu.fi (Antti Siivonen)
Subject: Re: macroevolution
Organization: University of Joensuu
Date: Mon, 31 Aug 1992 15:43:11 GMT

colby@bu-bio.bu.edu (Chris Colby) writes:
>Biologists know little about the genetic mechanisms of speciation. Some
>think series of small changes in each subdivision gradually lead to
>speciation; others think there may be a few key genes that could change
>and confer reproductive isolation. One famous biologist thinks most
>speciation events are caused by changes in internal symbionts. Most
>doubt this, however.

	And no names. 

>OBSERVED SPECIATIONS

>It comes as a surprise to some to hear that speciation has been
>observed. In the genus _Tragopogon_ (a plant genus consisting mostly
>of diploids), two new species (_T._ _mirus_ and _T._ _miscellus_)
>have evolved. This occured within the past 50-60 years. The new
>species are allopolyploid descendants of two separate diploid
>parent species. 

>Here is how this speciation occured. The new species were formed
>when one diploid species fertilized a different diploid species and
>produced a tetraploid offspring. This tetraploid offspring could
>not fertilize or be fertilized by either of it's two parent
>species types. It is reproductively isolated, the definition of
>a species. 

	No, you must say: It is not observed. This has also happened with 
	animals, but under certain conditions they can reproduce. This is 
	still micro. 
>are found. In short, it appears that species remain unchanged for
>long streches of time and then are quickly replaced by new 
>species. However, if wide ranges are searched, transitional forms 
>that bridge the gap between the two species are sometime found in
>small, localized areas.

	Lie. 

>For example, in Jurassic brachiopods of the genus _Kutchithyris_,
>_K. acutiplicata_ appears below another species, _K. euryptycha_.
>Both species were common and covered a wide geographical area. They
>differ enough that some have argued they should be in a different
>genera. In just one small locality an approximately 1.25m sedimentary
>layer with these fossils is found. In the narrow (10 cm) layer that
>separates the two species, both species are found along with 
>transitional forms. In other localities there is a sharp transition.

	What does it tell about their reproduction ? Sorry, find better 
	evidence. 

>Gould and Eldredge, the authors of punctuated equilibria, interpret
>this in light of theories of allopatric speciation. They concluded 
>that isolated populations of organisms will often speciate and then
>invade the range of their ancestral species. Thus at most locations
>that fossils are found, transition from one species to another will
>be abrupt. This abrupt change will reflect replacement by migration
>however, not evolution. In order to find the transitional fossils,
>the area of speciation must be found. 

	Like the Great Dane has developed from Chihuahua. Other dogs are just
	transitional forms. Sorry, no bonus. 

>mechanisms have been shown to work, there is still no consensus on
>the relative contribution of each of the mechanisms to the overall
>pattern of evolution within a lineage. Likewise, although new species

	You could have a good career in "America's funniest people". Consider 
	that. 
>Evolution is the unifying theory of biology. The functions of
>biological entities at all levels (populations, organisms, genes) are
>the product of a non-random factor (e.g. natural selection) operating
>in conjunction with random factors (such as mutation and mass extinction)
>within a framework of historical constraint. For centuries humans have 
>asked, "Why are we here?". A question such as that probably lies
>outside the realm of science. However, biologists can now provide
>an elegant answer to the question, "How did we get here?"

	Bullshit. 

	I know many biologists on the net and they are against evolution-      
	nonsense. Still you talk as if all biologists were for evolution. 
	You failed all your attempts to prove anything. Please, don't call
	evolution biology ! It has as much common with biology as UFOs have
	with astronomy. 

	I must say myself that I agree with microevolution. 
-- 

		Andreas - Siperian Sirri   Siberian Stint

	No ITU, love, evolution.           Tuusniemi ! Siis imein suut !