Saturday, December 1, 2007

What Can We Learn About A Cells’ Flagellum?

Last post, I looked at the factory like structure of the inner-parts of a cell. But though the cell is an amazing structure, it is truly amazing to see what the individual parts of a cell do and look like. In this post, I will look at the cilia/flagellum of a cell. Please don't let the sciency words throw you, I will try and keep this information so easy even a lawyer can understand it! J


Cilia are found in cells with a nucleus (eukaryotic cells). They are on the surface of nearly every one of the 250 trillion cells inside our human bodies. Cilia are thin, tail-like projections extending outwards from the cell body. But there are cilia even on one-celled algae. And when one cilium is cut off, another replacement cilium will re-grow in about one hour. That's a good replacement system!


Prof. Behe's first book was called 'Darwin's Black Box' and it described the flagellum (basically the same as cilia) on the outside of the bacteria's cells. Don't get thrown off if I say 'bacterial flagellum', it just means the extended whips on the outside of a bacteria cell. The flagellum is a slender whip-like projection that motors the bacteria's movement. In 'Edge of Evolution' Prof. Behe also discusses the updated information we have learned about bacterial flagellum in the last 10 years, and he does this through easy to understand illustrations. He likens the cilia to the construction of a tower, which is built from the bottom up. Although there is still much to learn about how cilia are built, we do know that the plans are contained in the cell's DNA. The DNA provides all of the information for what parts are needed to construct the cilia, what proteins are needed, how much is needed (controls that turn on and off), and directions for where they should go.


from Wikipedia entry for flagellum.


Just as an outboard motor on a boat consists of a large number of parts, so does the bacteria's outboard motor, the flagellum. The physical construction in the cell is done by proteins. Proteins basically do the same work as bulldozers, steam shovels, train engines, train cars, railroad tracks, and all of the tools you can possibly use on a construction project. What is really interesting is that there is a protein in the cell that is essentially a foreman of the construction project. It is not a part of the flagellum or the construction machinery. Instead, it tells the other proteins what to do. When a flagellum is needed, the foreman protein binds to the control regions of the DNA that turn on the making of the proteins used in the construction project. One after another, proteins are made that are necessary for the construction of parts of the flagellum. The picture above shows all of different and various parts that make up the bacterial flagellum.


And it only keeps getting cooler! One of the early construction projects of the foreman is to assemble a pump. When the pump is completed, it is directly linked to the switching on the genes necessary to make the final, last parts of the flagellum. The perfect timing, the original plan for the construction secretly hidden inside of the DNA, the proper turning on and off of the proteins needed to make the flagellum, and the use of sequences to make just this one small part of a cell is mind blowing. I know some people look up at the stars and see God's majesty in His handiwork. But when I see the workings of the inside of a cell, I am in awe as I see what He has done. I wish I could do a better job of describing all of what takes place in the construction of the bacterial flagellum, but my hope is that I have at least given you the flavor of what is going on in the microscopic world in our bodies.


So what is the point of all of this? Prof. Behe describes the construction of the bacterial flagellum as being "irreducibly complex". By this he means that just as a mousetrap has 5 pieces that are needed to make a functional mousetrap (the board, the spring, the latch, the arm, etc.), and the mousetrap WON'T work until it has all 5 pieces in place. In the same way, the bacterial flagellum must have dozens of pieces in place before it will work. And this is something that Darwinism cannot do. Instead, the Darwinist claim is that small changes will lead to the making of the machinery that is useful in a cell. But as this post describes, these are not small changes. You need lots of BIG changes to make the flagellum. And they all need to work together, and in the right sequence, and with a proper plan in place to begin with. This is the domain of something that is shown to be Designed, and not the work of random forces as Darwinism is.


The Irreducible Complexity of the bacterial flagellum points to Design of life here on earth. It is yet another example of the 'Consilience' of scientific evidence that shows we are part of God's creation. I hope you find this persuasive as well.



1 comment:

Edward Oleander said...

The main thing that I pull from Behe's flagellum arguement is that he has to keep reaching into smaller and smaller realms to maintain his IC fiction. He used to sprout on about eyes and wings. Now that the wing has a firm trail of fossil evidence and functional consistency, and the eye has been shown to also exist on an evolutionary continuum, he has to fall back yet again. Does he point out the thousands of differing types of flagellum, used for hundreds of purposes, that do not match his drawing?

Just like the "sun, water and rock" argument, he oversimplifies matters until they satisfy his needs, then calls it "science."