I think it is hard to say to what species most domesticated Ags belong. The
question almost is meaningless. Costatum? Modestum? Pictum?
And there are more and more intergeneric crosses in the plant trade; for me,
this is yet another indication that species are fluid, rather than
crystallized entities. Most recently, I read of a melon-cucumber cross in the
Park Seed catalog.
Species definitely are not entities in my view. They are names we give to
especially strong currents in the flow of genetic material which is life.
Wolves and dogs are interfertile, and so are their offspring, but we call
them different species.
Moving along to issues of selection:
There are on the market a number of noncorrosive drain cleaners which are
suspensions of bacteria repeatedly selected to destroy the slime which
narrows many drain pipes.
There also are industrially available suspensions of microorganisms selected
to do such tasks as eat the crude petroleum spilled around an oil well, or
eat the gasoline leaked around a service station.
And on a less universally-agreed-upon note, a strong case can be made that
HeLa cells constitute an entirely new species of microorganism, one uniquely
adapted to the man-made environment of cancer research labs, which are no
longer human cells. Many cancer researchers refuse to have them in their labs
because of the way that HeLa cells will invade other cell cultures, compete
with them, and actually destroy them. I understand that there also has been
some genetic drift from the original material taken from the patient
pseudonymously known as Helen Lane. Reasonable people may disagree, but I
think the evidence is good that HeLa cells can be called a species of
organism which has come about in our own era, evolved from human beings but
not human.
[By the way, speaking of controvery, has anybody read Barry Commoner's lead
article in the February issue of Harper's Magazine (not to be confused with
Harper's Bazaar)?]
Finally, I want to make a suggestion which I hope merits your most serious
consideration: I suggest that anti-evolution sentiment has turned into a
defense of the notion of species as real entities, or essences. As you can
tell from what I have written above, I do not think that species are real
entities; I think they are simply groups of organisms manifesting many but
not all traits in common. I am not a fan of the "jump" or "sudden break"
theory of evolution; I am a gradualist.
What this all implies is: I personally suspect that anti-evolution beliefs
are arguing against a straw man. Personally, I would like to see an
antievolution case made against gradualist evolution.
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