How's this for an empirical example. A strain of bacteria are exposed to a
man-made (not found in nature) antibiotic. The vast majority of the
bacteria die, but not all at once, because some are not immediately exposed
to it as it diffuses through the colony. As such, these bacteria continue
to grow and divide until killed by the antibiotic. In any event, some of
these new bacteria acquire a rare mutation that produces an enzyme that can
react with a chemical moiety on the antibiotic. Normally, in a natural
population, this enzyme has no substrate (the chemical moiety does not exist
in nature), so the bacteria that acquire the enzyme feel no pressure to keep
it and it is quickly lost from the population; in other words, it is not a
normal part of the strain's genetic makeup, and it occurs rarely. This
time, however, when these new bacteria with the mutation encounter the
antibiotic, the enzyme produced by the mutation attacks the chemical moiety
on the antibiotic and cleaves it off, thus rendering the antibiotic
impotent; in other words, the enzyme destroys the antibiotic. All the
bacteria that have this mutation survive exposure to the antibiotic; all
those that do not die. Thus the new gene created by this mutation becomes a
permanent part of the strain's genetic makeup.
These experiments have been done and have been documented, so it counts as
empirical evidence; the genetic makeup of the strain has been increased and
an enzyme with a new function that never existed before now exists
permanently, so it counts as an increase in complexity; the frequency of the
allele that produces this enzyme has changed from practically zero to
practically 100%, so it counts as evolution. Therefore, by my definition of
evolution as well as yours this strain has evolved.
>
>> You seem to be asking for an example of nature creating large amounts of
>> complexity very quickly, but that's a strawman. There are 3 billion
>> bases
>> in the human genome, and only about 5% of them code for proteins. This
>> complexity evolved over 4 billion years, which means it took nature about
>> 27 years per base on the average.
>
>Scientists have worked with thousands of generations of fruitflies under
>circumstances of increased mutation and selection rates without creating a
>more complex creature.
>
You have consistently refused to define complexity as it applies to
evolution, yet you do agree with one possibility in which complexity is
defined as bigger, with more cells, more organization and more
specialization of these cells. If we use that definition then in fact
experiments with fruit flies that produce individuals with two pairs of
fully functional wings (fruit flies only have one pair of wings) or eight
fully functional legs have created greater complexity. And I'm not just
talking about a greater number of parts (though that would be enough by the
above definition). I am also talking about the more complex system of
muscles and nerves, plus the extra wiring in the brain, needed for these
extra parts to be fully functional.
And based on the way that biologists classify flies and insects, a "fruit
fly" with two pairs of wings is no longer a fly (flies have only one pair of
wings) and a "fruit fly" with eight legs is no longer even an insect, so
these experiments not only demonstrate increased complexity (using the above
definition), they also demonstrate macroevolution.
>
>And, when I say that the concept of increasing
>complexity is foreign to nature, that isn't limited to biological
>evolution.
>You're free to provide an example in a non-living system.
>
Using the definition outlined above we can say that anything is more compex
if it is bigger, with more component parts organized into specialized
structures or functions. Two non-living systems immediately spring to mind.
Elemental nucleosynthesis in the cores of stars and during supernovae create
more complex elements from simpler elements by fusing simpler elements
together. The new elements are more complex because they are bigger and
have more component parts organized into specialized structures than the
simpler elements they were made from.
The second example is the formation of rocks from simpler chemicals.
Limestone begins with calcium and carbon dioxide dissolved in water. The
carbon dioxide reacts with water to form carbonate, a soluble molecule; the
carbonate combines with calcium to form calcium carbonate, an insoluble
compound; calcium carbonate compounds combine to form calcite, a crystalline
mineral; calcite and other minerals combine to form limestone. Each stage
is more complex than the last, because each successive stage is made of
components from the previous stage arranged into larger structures
containing more components organized into specialized structures.
No doubt you will dispute the definition I am working with; in that case
please feel free to provide your own.
>
>I would be
>satisfied even with a computer simulation that provided an indefinite
>increase in complexity. In a very short time you could simulate millions
>of
>generations of mutation and selection. However, all such efforts have been
>completely failures.
>
Not by the above definition they haven't. Even Dawkins' rather crude
"biomurph" program produces "organisms" that are often more complex than
their predecessors.
>
>> Now I can understand if you want to say that the process has not been
>> demonstrated, but you're making a much stronger statement. You're saying
>> that "empirical science squarely demonstrates" that evolution is wrong.
>> I don't see how you can possibly support that statement.
>
>Sandcastles don't form on beaches because of wave action.
>
That's not evolution.
>
>We don't observe species increasing in complexity. Etc.
>
That is evolution, and we do observe it; we can breed our own.
>
>> But scientists do not claim that evolution will result in an indefinite
>> increase in complexity. And even if it were so, how could you possibly
>> demonstrate it? The correct question is, "Can the proposed mechanisms
>> of evolution account for the amount of complexity that we see today?"
>> And so far, we haven't seen any reason why they can't.
>
>Unless you believe there is a definite limit to how complex life can
>become, you believe that complexity can increase indefinitely.
>
That again depends upon how you define complexity; some definitions permit
it, some do not. How do you define complexity in this context?
>
>And, the proposed
>mechanisms of evolution have never been shown to increase the complexity of
>organisms.
>
Using the definition for complexity I outlined earlier, these mechanisms
have in fact demonstrated an increase in complexity.
>
>Species, over time, are observed to become less complex (or even
>extinct).
>
By the definition of complexity I have been using, you are describing
parasites. Besides, once a species forms it remains stable; at best it
merely adapts to changes in the environment (so-called "microevolution").
By your own definition any "indefinite" change in complexity is evolution,
so if a species did become less complex it will have become a new species.
Species do not become extinct because they loose complexity; they become
extinct because they cannot survive a change in their environment. This has
nothing to do with complexity. One environmental change might wipe out all
so-called "complex" lifeforms but have no affect on the simpler ones;
another completely different environmental change might wipe out these very
same simple lifeforms while leaving the more complex one alone. What
determines who survives and who doesn't under these circumstances is who is
lucky enough to have a genome that allows them to survive the change, and
that genome can be complex or simple.
Kevin L. O'Brien