[snips]
On Sat, 03 May 2008 09:08:58 +0200, ~saba*gracile~ wrote:
>>>> What is the theory of evolution, in your own words?
>>>
>>> survival of the fittest in an environment to pass down more likely
>>> genes?
>>>
>>>
>> So, there's no evidence of that?
>
> All the time. No fish ever becoming something of a land creature though.
> Never happened.
Let us for the moment assume that this is true - no evidence exists of a
fish becoming a land creature, or similar large-scale changes.
The definition offered - offered by *you* - is this: "survival of the
fittest in an environment to pass down more likely genes."
This definition does not _require_ evidence of large-scale changes; it
simply requires evidence of survival of the fittest, that is, it requires
observation of competition and the observation that within a competitive
environment, some organisms compete better than others - the "fittest"
survive, thus passing on their genes.
These have been observed. Thus, we know that evolution, as per your own
definition, exists, is real, happens.
However, your definition leaves out two key points. One is the notion of
an influx of new information. Fortunately, we have such a source, in the
form of mutation (among other things). The other is the notion that
environments themselves can change.
Now we have something to work with. New information - new genes - are
introduced into the gene pool. Competition - "survival of the fittest" -
sorts out which genetic makeups continue and flourish, which get cut
off. Changing environments - whether due to climate change, introduction
of a new predator (or prey, or food source...) or simply part or all of
the population moving to a different location - likewise affect the
specific nature of "fittest"; the term applies to survival _within an
environment_.
Good, good. We have a source of new information, we have the ability to
pass on that information, we have competition to weed out the dross and
retain the beneficial, we have changing environments to drive divergent
selection pressures.
All good, all wonderful, all observed, and all amounting to - we're all
agreed on this point, I'm sure - small-scale changes. A population of
light grey fish becoming a population of dark grey fish, that sort of
thing.
Agreed? Good.
The usual creationist tactic in this situation is to admit
"microevolution" - by which they mean small-scale changes such as
populations of fish changing colour, but not "macroevolution", such as
populations of fish developing limb precursors and eventually producing
land-based animals.
The problem is, they've already admitted so-called "micro" evolution,
thus to make their argument that _it_ is okay while "macro" evolution
isn't, requires the establishment of some sort of barrier, one which has
never been defined, let alone demonstrated.
Here's a visual model of the problem this creationist argument gets into:
Take 100 pennies, put them on the table in front of you; this
represents the _current_ set of changed genes in a population (i.e. the
"small changes" which have accumulated so far.)
To this, add a penny - a small change, the sort _expressly_ allowed for
by the acceptance of "micro" evolution.
Add another penny - another small change.
Continue this process with another penny, another, another.
Anyone capable of counting past one should be able to grasp three things
about this process:
1) It uses nothing but allowed "small changes"
2) It *will*, soon enough, turn that single dollar into two dollars
3) Given more time, that single dollar will become ten dollars, a
hundred, a thousand, a million - any scale you want
By allowing "micro" evolution, by admitting even the possibility of it,
the results are inevitable: large-scale changes are a predictable, an
obvious, even a necessary outcome of the process.
Yet they don't admit "macro" evolution. Why not? No idea. Some
complain about "lack of evidence", yet the very process they agree
happens is sufficient evidence on its own to show such large-scale
changes inevitably will occur, so that's no argument.
No, there are only two ways to "stop" this so-called "macro" evolution.
One is to deny _any_ evolution occurs - but then you're claiming that
observed processes don't actually happen, and you're a crank.
The other is to demonstrate a barrier involved, something which allows
_some_ change, but not _that much_. This would, of course, be a major
win for the creationist cause, but sadly, no such barrier has been
described, let alone demonstrated, so really, the creationist is left
with the alternatives of either trying to claim observed phenomena don't
happen - i.e. being a crank - or simply asserting that the large-scale
changes "can't happen, just cuz".
Well, there's a third option: they could learn some science. Learning,
however, is not high on the list of creationist priorities.
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