Re: En: species, subspecies, strains, populations, races etc.

[Mike & Diane Wise <apistowise@bewellnet.com>]

I've been reading all these comment with interest. It just goes to show you that
even scientists don't have a fixed definition of a species. geneticists, physical
taxonomists, etc. have different definitions. The trick is to decide on what you
personally feel is important in differentiating populations of fish, birds,
trees, etc. Personally, I tend to be more interested in physical taxonomy
(physical features bear the most importance) because this helps be identify the
many forms of Apistogramma. I really don't care if 2 different forms are actually
genetically the same. I don't knowingly mix populations in my tank so I don't
care what the form is - whether it's only a color form of a species or a separate
species altogether. For most of us I bet we feel the same way.

Now I'll put my 2 cents in on some of the comments.

"José J. V. Carvalho" wrote:

> What would you say if population A' (that can breed with sp. A but not with
> sp. B) and population B' (vice-versa) can interbreed? All of this being in
> mind that it MUST be natural.

I imagine it occurs, but I don't know where - maybe Lake Malawi. I imagine that
we would be seeing recent speciation occurring. This is where the biological
definition breaks down. Maybe scientists care, but I sure that the fish do not.

> The guppy was introduced in Brazil as a larvofagous (is this right?, help me
> Tsuh) and now, here in Sao Paulo, we can collect the "barrigudinho-pintado"
> (Poecilia vivipara) with many patterns of guppy. In tanks or ponds they
> interbreed freely, but once the introduction was artificial, we can't say
> that they are of the same species.

This is the same that occurs in captive bred Mbuna. They have evolved from their
common ancestor so recently that even species in different genera can
successfully reproduce.

Lars wrote:

> By the way, I believe that humans easily satisfy classical criteria for
> subspecies, although we are blurring the lines by moving around so much in
> recent times.  We get around that by calling ourselves different races - a
> category without taxonomic recognition.  However, I'm with Mike W. in
> considering all of us to be the same family.

My question is how recent is "recent". Our species has been moving around the
earth for at least 100,000 years. We are natural explorers so I imagine that
populations have been introduced to infusions of "new blood" for the last 1000
centuries. I agree with Tsuh Yang. What we call "races" is too "fuzzy" a term for
taxonomy. Taxonomically maybe we should look at each ethnic group more as a
distinct population within a species. Personally, I'm a mongrel of several
central and western European populations. I have Celtic, Pictic, Germanic, and
Slavic genes all mixed up in me. Hmm. Maybe that's why everyone I knows says I'm
weird. Personally, I like to consider it "hybrid vigor"!

Tsuh Yang wrote:

> on humans:
> >  It has been tried with genetic material recently. The results were very
> > weird to say the least. It seems that no matter what racial or ethnic make
> up we have,
> >  we are all identical genetics-wise. We all have the same mitochondrial DNA
> in
> > us, meaning we all have the same great-great- great- ... great grandmother
> > somewhere back around 200,000 year ago (I guess there was an Eve).
>
> i believe there is a skeleton found in ethiopia that has been dubbed that, as
> it is older than lucy and i think they sort of traced all human DNA or
> ancestry back to that population to which she belonged.

Yes, but this was a completely different species altogether (Australopithecus sp.
X). Lucy (Australopithecus afarensis) is close to 2.5 million years old. Either
might be our direct ancestor, but if these species were around today I doubt that
we could interbreed successfully, and we certainly were morphologically different
(we're the ugly ones). The "Eve" I was discussing was a primitive form of Homo
sapiens, the same species we are. These we could interbreed with successfully
(supposedly). Eve is not actually a fossil but her genes are found in every
person so far genetically tested.

> >  I hope not. I like to think that everyone out there is part of my family.
>
> sorry, mike, but there are some relatives i'd wish were not part of MY
> family... :-)

Excellent reply! I love it.

Mike Wise

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