Tuesday, January 31, 2012

Creation vs Evolution: Part 2 - Macroevolution and Microevolution

When I was teaching a class from a curriculum I am working on entitled “Apologetic Creationism” in a Christian high school, I astounded my students by making a bold claim. I started off one class by saying “Evolution is a proven fact”. This brought a lot of surprised looks from the students, who had been brought up in an environment that shunned any type of evolutionary thinking.

However, I stick to my claim. Evolution is a proven fact. What is not proven yet is the Theory of Evolution as pertaining to the origin of life. To understand what I am saying, we must understand the difference between micro evolution and macro evolution.

Macroevolutionary studies focus on change that occurs at or above the level of species1. In basic English, this is the idea that entire gene pools can change, allowing one species to eventually or abruptly become another species. This is the premise on which the entire Theory of Evolution is based, that one species became another, which became another, and so on. If this is true, then it is very possible that a single celled organism could eventually become a complex life form. I will deal with problem areas with this thinking in other posts. I am simply posting it here to contrast the differences in microevolution and macroevolution.

Microevolution is the changes in allele frequencies that occur over time within a population.2 This is what has been proven time and time again, only to be misused by those on the side of evolution, and many times discredited by those on the side of intelligent design.

Even those that are the most staunch defenders of intelligent design must accept microevolution as simple fact. For example, intelligent design proponents believe that we were all descended from one couple. For those that believe in the great deluge (flood), that couple was Noah and his wife. For those that do not believe in the great deluge, they point to Adam and Eve. Whichever they believe is not relevant to this discussion, only the fact that they point to a single couple as the origin on human life.

If we all descended from a single couple, then why don’t we all look the same / similar? Where did the different races come from? Why are some of us white, some black, some tan? Why do we have differing hair textures? Eye shapes? It’s because we all adapted to our surroundings as needed. We “evolved” differently.

Take a simple hypothetical case study:

A man and a woman move to an uninhabited island. They have 6 kids, 3 boys and 3 girls. With no one else to marry, these children marry each other. Their children would adopt the dominate traits of their parents. In one generation, these traits wouldn’t be too diverse. But after time, other dormant traits would begin to appear. Maybe one group were more muscular. Maybe one group had red hair predominantly. Maybe a third group were shorter.
Well, as is the case in any society, people with the same physical traits tend to flock together. Since the shorter ones would tend to hang out with the shorter ones, they would naturally find a mate amongst the other shorter people. Since both parents carried this trait most, if not all, their children would also have this trait. The same would go for the muscular people, and the people with red hair.

Eventually you would have three distinct groups of people: those with red hair, those that are short, and those that are muscular. The dominant traits defined who they were.

Natural selection can also play a role, as much as intelligent design proponents hate the phrase. If there were two families of giraffes, one with shorter necks than the other family, then there would be a problem. The giraffes with the longer necks could reach both the leaves low on a tree and up high, while those with shorter necks could only reach the lower leaves.

Since two groups would be eating the lower leaves, and only one group the higher, eventually the lower leaves would be eaten at 3 times the rate of the higher leaves, assuming equal amount of both families, and equal ratio of lower to higher leaf eating among the long necked giraffes. When the lower leaves were all eaten, then 2/3 of the higher leaves would still be left for only half the population, sustaining them easily. But since the lower leaves are gone, the short necked giraffes would die, and the short necked trait would die with them.

This is microevolution at work through natural selection. Those that lack the traits to help them survive eventually die out, leaving those with the trait needed to survive alive. This has been seen with moths in a smoggy city, where the smoke colored moths survived while all the black moths were eaten by birds. And so the black color trait died out.

Now, in these two scenarios, it must be pointed out that the traits were already existent. They were dormant in the first scenario, and already dominant in the second scenario.

I hope this explains microevolution and macroevolution. Next post will be the first problem for evolutionists: the bombardier beatle.

   - Sapper Woody





References:
1 Dobzhansky, Theodosius Grigorievich (1937). Genetics and the origin of species. New York: Columbia Univ. Press. p. 12. LCCN 37033383.
2 http://evolution.berkeley.edu/evolibrary/article/_0_0/evoscales_02 

1 comment:

  1. Brilliant post. That's what I love about you, you take in both sides of the argument and present them in a very fair fashion. I'm quite interested in what else you have to say on the subject.

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