Monday, September 16, 2013

How does a bacteria become a man? Is evolution just a silly idea?

By Aaron Sherman

I've been watching a syndicated evangelical show called Wretched on YouTube that has a terrible video up about evolution. I'm going to ignore their hostile and downright abusive quick-cut interviews in which they try to get evolutionary scientists to explain the impossible. Instead, I'll focus on their thesis which is summed up at the start: a creature can't turn into a different kind of creature via speciation. This is absolutely true and their further conclusion is also absolutely true: there is not one shred of evidence of one creature turning into another kind of creature via evolution.
So, case closed, evolution is bunk, let's all go out for pizza. Right?

Well... no. Let me explain.

First, I want to note that I understand that not all members of Abrahamic faiths are young earth creationists. Most Jews, nominally all Catholics and many Muslims subscribe to theistic evolution. That accounts for a huge subset of the world's population. I'm addressing the views held by the very vocal minority who made the video linked, above.

Evolution is a slow process. That phrase probably brings to mind pictures of slow-motion cameras, but you don't quite have the ability to comprehend just how slow evolution is. Imagine that you had the reverse of a slow-motion camera that only took one picture every 20 years. 20 years is a "generation" or about the span of time, on average, that one generation of humans will produce another generation of humans. Many have children younger, many older (this number was established before birth control, so it's not as accurate now as it once was... the average first child age of motherhood is 25, now in the US).

At 24 frames per second, the movie that that camera made would have no evidence of speciation after 1 second.... 10 seconds... 1 minute... and even 3 and  a half minutes! To jump back to the previous species before H. sapiens, you must travel back over 100,000 years! But even after 200,000 years when there were, as far as we know, no H. sapiens on planet Earth, there were still members of our close-knit "genus," Homo as far back as 2.3 million years ago, over 20 times longer than the entire existence of H. sapiens! We're now talking about well over an hour of our film that still has not shown us a new genus from which humans arose.

Our nearest ancestor of another genus is the now extinct genus Australopithecus which evolved sometime around 4 to 5 million years ago. But typical young Earth creationists who use the "kind" argument are not satisfied with changes in mere genus. In some cases, they move the goal posts all the way out to whole domains when they suggest that bacterial evolution just produces another bacteria! To understand how absurd this is, here are two examples: E. coli and C. tepidum a form of green sulfur bacteria that's closely related to those found at undersea, volcanic vents. These two bacteria are the same "kind" according to the video, but they are likely separated in terms of the divergence from a common bacteria ancestor, by billions of years! They have almost nothing of their habitats or means of survival in common and E. coli has over twice as many genetic base pairs as C. tepidum! They are closer cousins on the evolutionary tree than humans and the X-ray fish! But to the interviewer in this video, they are "the same kind." This demonstrates just how absurd such an attempt to classify life by a few simple attributes can be.

Ah, but the astute reader recalls that I started off by saying that evolution never produces new "kinds". Well, I'll admit that I was being overly broad in that statement. Let me be very specific: you will never be able to look at the offspring of a creature and say, "that is a new genus!" It simply doesn't work that way. You could wait billions of years and you would never see that happen. The offspring of a human will always be a human. At some point, the word "human" will either subtly change in meaning or become too unspecific to be useful and you'll want to use a new word, but you'll never be able to pick the specific generation where that happened. Why? Because it doesn't happen over a generation. It happens over hundreds of thousands of generations. One one-hundred-thousandth of the change required to become a new "kind" in the shortest period that makes any sense to talk about would be undetectable without genetic analysis, and even then genetic variation occurs all the time, so you can't just see any change and say, "that's the line."

What young Earth creationists are asking us to accept is that evolution is wrong because we can't demonstrate events that can only be measured in terms of millions or even billions of years. Well, if that's where they've had to move the goalposts, then I consider that as ringing an endorsement for the theory of evolution (see my provisos about  how overly broad "evolution" is as a term) as we're ever likely to see until someone invents time travel.

But if you really care about the science, understand this: if, as YECs claim, the Ark sent forth just a few strains of creatures 4,500 years ago that were all created individually by the hand of God, then there's an awful lot of evidence that just doesn't make sense. For example, all of those species have DNA that makes it look like they are related. They don't look like unique creations on a genetic level, but like members of a very large family tree. In fact, there's no evidence at all for this massive shift in evolutionary timescales necessary for post-flood evolution to have happened.

I don't begrudge YECs their views. It's perfectly acceptable to believe that the world is literally 6,000 years old and that God likes to confuse humans by planting evidence to the contrary. But the denial of the evidence to the contrary is what's problematic, here. If our public discourse is built around calling people liars for observing what's in front of them, then we're going to have a very dysfunctional society.