Quote:
Originally Posted by CSchultz
Irreducable complexity has all but destroyed the entire concept of Darwinian evolution as well. You see, there is a point at which the complexity of an organism cannot be reduced, (De-Evolved) without making it impossible for that organism to have existed in the first place.
|
Actually it hasn't. Irreducible complexity has actually never been proven and there are evolutionary methods that have been discovered that can actually produce many of the examples that were previously given by IC advocates.
Quote:
|
Bacterial flagellum is just one example of this. Bacterial flagellum is an organic propellar and motor assembly attached to the rear of many small bacteria. It is made up of over 40 individual components, each one equally necessary for it to function.
|
Each one is necessary for it to function the way it does. Does this mean it couldn't have evolved? Absolutely not. If you remove several of the parts you still get something fully functional. The bacterial flagellum being irreducibly complex specifically has been debunked. You can break the flagellum down into simpler parts that all have their own function. Starting with a simple passive pore to a selective pore, both are function at getting proteins into the periplasm (the latter actually selects certain proteins). The F1F0ATP Synthase is ancestral to the flagellum and can transport proteins. The Secretins are another piece that helped form the flagellum and when alone it transports proteins out of the cell. Adhesive proteins can become bound to the secretins which eventually will form the pilus (which can wiggle) which increases the chance of finding a substrate to attach to. The Tol-pal system, which alone functions to to transform protein across a membrane, causes the pilus to spin in a poor fashion. But this poorly spinning motion will increase dispersion allowing the bacteria to escape environments were nutrients are low. By this time, it is a proto-flagellum and still functional though not yet the Bacterial flagellum. The outer membrane of the sectretin splits to become the P-ring, which stabilizes the proto-flagellum to move more freely. Signal transduction proteins bind its function specifically to the environment. Out of the 42 proteins that make up the flagellum, 40 are found in other systems. Each step of proposed evolution of the flagellum only needs the addition of a single protein, each step is functional and has a selective advantage over the previous form. Model was predicted in 2003, and confirmed through several experiments.
Quote:
|
I will agree that he had a pretty good theory, but it hasn't withstood 100 years of scientific discoveries.
|
Though not everything he stated has help up. His important ideas of natural selection, and the hypothesis of common descent that went with the theory have held up.
Quote:
|
Originally Posted by Tyler1
He didn't need to explain on the molecular level how organims change over time just that they do. So, now we know that it is caused by variation in DNA, organisms still adapt to different environemts if the adaptation exists in the population.
|
Indeed he didn't need to explain, but he felt that he did at some point and when he did he was wrong. Now we know what the true causes are.
Quote:
|
Isn't punctuated equi. when a large population experiences a decrease in the number of organisms in a population able to pass on genetic info. so they have changed, like a bottle neck, my science is a little rusty. I need to do a little reviewing.
|
Bottle neck is a type of punctuated equilibrium. But in PE in general it is not necessary to have the large population in the first place. Punctuated equilibrium basically shows how swifter changes and quicker speciation occurs. This actually does show something that Darwin's theory did not and causes a lot quicker speciation under the right circumstances.