Sunday, February 26, 2012

The Transitional Forms Argument

Time for another post on refuting creationist arguments!

Where Are The Transitional Forms?

Here's something I've been tempted to talk about for some time now but figured I might as well leave it for people who professionally study biology. Then I thought, “screw that!”, I think I might be able to help clarify why this argument is ridiculous to the creationists who still like to use it.
The fact is, every living creature alive today, and every living creature that lived in the past, is a transitional form. Evolution is an on-going process and not in the way you imagine it.
Evolution does not work out a blueprint for its ultimate goal and set it underway for thousands of years or more. It is not a mystical force present in a creature that says, “Hey, I'm gonna give my offspring the starting point for wings so that many many generations later, my species will be capable of flying!”
There is no final destination for evolution, we're all in the midst of evolving now and that will still be true in a few million years.
What I find especially peculiar about this argument is that it's usually followed up by a claim that evolution should produce 'half-and-half' fossils; like a skeleton that is composed 50% of ape-like features and 50% of human-like features.
If you don't see the incredibly obvious flaw with that understanding of evolution, repeat the following sentence until you do: We are not Lego!

In fact, let me represent this perception of evolution with Lego: I have two blue bricks stacked and two red bricks stacked and I say that the blue bricks are the descendants of the red bricks.

According to this creationist argument, there must be a stack of one red brick and one blue brick to fill in the gap.

This is an egregious misunderstanding of what evolution theory actually describes. We could much more accurately describe it with a gradient.
If we open up Photoshop, or GIMP, or whatever, and make an image that is 101 pixels wide (I'm making it an odd number for a reason) and however high (doesn't matter for this example) and make a gradient that goes from totally red to totally blue, then we can observe a very gradual change in every column of pixels.

Note that nowhere in this gradient is there a column that's composed 50% of blue pixels and 50% of red pixels. Instead, we have a column in the dead centre (this is why I made the width an odd number) that is one solid colour made from an even blend of red and blue. We, of course, know this colour as violet.
This column does not show half of it's features to be decidedly blue and the other half to be decidedly red, it is just one more step in the gradual change between the two.
And just like the midway point of the gradient isn't 'half-and-half', the midway point between two species wouldn't look like a cobbled mess of parts from the species it rests between.

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