Monday, 21 February 2011

Creationists: not so smart and honest.

Browsing Youtube today, I came across a video entitled "Why do SMART AND HONEST people laugh at Darwinsits?". With a title like that, I knew I had to watch it. Here it is, below:

The guy's argument is this: the scenarios used by evolutionary biologists to explain the giraffe's long neck are completely implausible (and smart and honest people, apparently, laugh at them). According to him, biologists claim that the giraffe's neck grew longer to reach leaves higher up on trees, and all the shorter neck giraffes died of starvation because they were "too proud" to bend their necks down and eat the grass on the ground. Why, he asks, did none of the other African animals also grow long necks? Why didn't the giraffes just eat the grass on the ground? This scenario is ridiculously laughable, he says. Silly biologists!

The problem is that he has a less than tenuous grasp on how evolution works and hasn't a clue what evolutionary biologists actually say on the issue.

The currently favoured hypothesis in evolutionary biology is that the giraffe's neck is an example of runaway sexual selection, not natural selection via resource competition. Male giraffes routinely use their neck in "necking" competitions - mating displays that males use to establish dominance and win the fancy of females. Just like the peacock's tail, the giraffe's neck grew longer and longer in response to the ladies' preferences. Shorter neck giraffes did not "die of starvation"; they had a harder time wining mates and this negatively impacted their reproductive fitness. Why don't the other plains animals have long necks?  Because this sexual selection process didn't occur in other animals.

But even in the absence of sexual selection, the giraffe's neck can be explained by ecological selection alone. Those giraffes with longer necks had access to greater resources than those with shorter necks (that is to say, not only could they eat the grass, but they could eat leaves higher up on trees, too). The long neck giraffes, then, had greater reproductive fitness than those with shorter necks. The alleles for longer necks became more and more prevalent in the population; the alleles for shorter necks became less and less frequent. The short neck giraffes did not "die from starvation", the short neck alleles were weeded out over time. The video's creator asks "why didn't the short neck giraffes just eat the grass?", and if he thought about it for a second, he would realize that they did. It was competition from the other grazing animals that prompted giraffes to find resources else where; those that could eat both the grass and the high leaves had an advantage!

So why do smart and honest people laugh at "Darwinists"? They don't. They laugh at fools trotting out tired creationist canards without doing a moment's research.

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