http://www.cs.colorado.edu/~lindsay/creation/evolve_irreducible.html
Scenario #1: reduction of function
Scenario #2: loss of scaffolding
Scenario #3: duplication
Nelson:
Lets examine these three scenarios. The example he gives for scenario #1 is
The Bolas Spider. This site is much better in that it gives a just so story,
BUT then it backs it up with an example.
"This system is Irreducibly Complex. Without the glue, the moth wouldn't get
trapped. Without the web, moths that fly by (as opposed to landing by the
spider) wouldn't get caught. Without the pheromone, there wouldn't be enough
moths in the area. The web swinging behavior is reducible, though. There is
a cave-dwelling fly larva which attracts prey with a light, instead of a
smell. It has a single-strand web, but doesn't swing it."
Is it irreducibly complex? Lets apply the definition.
What is the function of the system?
"The bolas spider mastophora uses an unusual prey-capture system."
Ahh I see it catches moths so that the spider can eat. What are the parts to
the system?
"It spins only a single short strand of web, at the end of which is a drop
of glue. Then it swings this strand around in circle underneath it. At the
same time, it releases a scent - a pheromone - that attracts male Noctuid
moths. A moth flies into the area, hits the glue, and sticks."
I see so there are three parts to this system, web, glue, and pheromone.
If I remove pheromone, will this prey-capture system still work? Yes I can
remove the bait and it will still trap the occasional moth that stumbles
onto the trap.
So I have reduced this three part system to two. Perhaps it is a two part IC
system? Nope, the parts are not well-matched.If the length of the silk
strand is reduced , you don't need to change the glue to accomade it, and if
you double the size of the silk strand you don't need to change the glue.
And of course the author forgot the fact that the spider needs to reel in
it's catch. Now we have an intelligent agent as an essential part of the
system! The spider knows, has foresight, and makes choices to direct the
events of this prey-capture system.
Gene duplication and scaffolding has never been observed to produce any kind
of system. It relies on pure chance and assumes plasticity among the parts
of IC system. Gene duplication produces gene silencing.
This archive was generated by hypermail 2b29 : Mon Sep 18 2000 - 12:38:42 EDT