On 11/05/2006, at 8:39 PM, Nick Arnett wrote:
We have a LOT of direct evidence. The fossil record. Genetic drift,
actual speciation events.
We apparently define "direct evidence" differently.
What would you regard as direct evidence, and what do you mean by
evolution, as there are a number of meanings depending on context?
If you mean just evolution (the change in form over time which is
what evolution itself is), then the fossil record is direct evidence
showing that organisms have evolved through time, as is selective
breeding, as is comparive anatomy, as is the chromosomal fusion
showing that
If you mean speciation, we have observed the evolution of new species
of micro-organisms, those that metabolise nylon. Nylon did not exist
before the 1920s, there are now species of bacteria that digest it.
Totally novel adaptation, totally new species. There are other
documented speciation events in the literature, including in
_Drosophila_ fruit flies.
If you mean evolution by natural selection (the mechanism which seems
to account for much or most observed evolutionary change), then gene
ratios changing with selection pressure (like the widowbird
experiment described in Dawkin's _The Blind Watchmaker_, or neutral
drift in the absence of pressure) is direct evidence.
It's just wrong to say there's little direct evidence, sorry.
<sarcasm>Well, thank you for straightening me out on that. Now
would you
please introduce me to the people who have directly observed
evolution?</sarcasm>
Me. Worked at a laboratory looking at malaria (_Plasmodium_ sp.,
mainly _falciparum_ and _vivax_). Got to see both antimalarial
resistance, and antigenic evolution in action over the course of a
fascinating summer (punctuated with a rather nasty bike crash that
left me trying to do malaria assays down a microscope while
recovering from a fractured skull and concussion...), So I've
directed observed evolution, albeit _in vitro_.
Plenty of directly observed evolution at various levels in the
literature.
This doesn't count: http://www.darwinawards.com/
Bacterial adaptation almost does.
*Almost*? How is it *not* evolution?
Charlie
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