Re: [asa] evolution question

> I accept evolution because of DNA evidence, but I still wonder why evolution
> can't be shown in the lab... for example, creating a new creature from fruit
> flies. It seems like under controlled circumstances, we should be able to
> do things quickly that might take nature millions of years to do.

Three main problems:
1) How do you decide that it's different enough to call something new?

For example, the mutant fruit flies with legs instead of antennae have
8 legs, zero antennae, three body parts, etc. This does not match the
definition of any of the classes of arthropods and on that basis could
be considered an entirely new class. On the other hand, it's a mutant
fruit fly. (Note-loss of wings has worked for some flies. The sheep
ked lives and looks a bit like a tick, but it's a wingless fly. Some
fruit fly-like species in New Zealand lost their wings and live(d)
commensally with bats, feeding on the fungi that grows on the bat
droppings. One species went extinct when its bat went extinct; the
other New Zealand native bat and associated fly are endangered).

2) Who wants to make new kinds of organisms?
There's neither significant interest nor significant funding for such
an effort. Some studies have tried to look at speciation and related
genetic factors, but not many. There's also the experiments where a
single bacterium is cultured for a long time, with some variation in
environmental options, and the new kinds obtained at the end are
studied. A species of bacteria is problematic, however-they can swap
DNA around so easily that relationships are networks, and also it's
not that easy to come up with fine-level differences between things
that small. Probably the majority of biology research is relating to
medical applications. A large portion of the remainder is cellular,
biochemical, etc.-how things work within a cell, not much concerned
with what kind of organism it is. Many other areas of biology
likewise do not concern themselves with the origins of new taxa. The
only area that has historically really tried to do that is
agriculture, and there the focus is on making something useful, not on
the evolution itself.
Caveat-if more funding and emphasis were placed on evolutionary
studies, it would help me get a job-I'm not fully impartial.

3. Amount of time
Although evolution under experimental situations is indeed a lot
faster than the apparent average background rate from the fossil
record, there's still a whole lot of time involved. More importantly,
major groups are defined in hindsight. Insects are generally treated
as a distinct class of arthropods even though the evidence strongly
suggests that they are merely specialized crustaceans. If there were
just a few hundred species, they probably would be an order of
crustaceans. Several million species, most able to fly, with a wide
range of forms, and they get more attention.

If we stuck the mutant fruit flies on a remote island or in a
greenhouse in a space probe or somethign like that and left them there
for millenia, they might thrive and develop into something quite
different from an ordinary insect. Future taxonomists could then
recognize the mutant fly as the origin of a major group, but we can't
tell that yet.

-- 
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.