I remember being a sophomore in high school when my biology teacher announced that we would be studying evolution in the coming weeks. Honestly, I was excited.
That might be surprising since macroevolution is inconsistent with my religious beliefs. But I understood that if evolution turned out to be true, it would mean an error in my hermeneutic, rather than necessarily indicating error in God’s words. I didn’t feel threatened by the theory, I felt intrigued by it.
I also understood that the truth has nothing to fear from investigation. If my religious views were correct, there was no reason not to test them thoroughly. So what I had heard so many adults get so upset about, I saw as a personal opportunity to seek out the truth for myself.
Despite a fairly large section of my textbook dedicated to the subject, I was truly shocked by the lack of conclusive evidence in the book. There were a few vague statements about genetic mutations, and numerous, exhaustive examples of natural selection. It was as if natural selection was evolution at work and we should need no further proof.
Natural selection is very easy to understand. In any given environment, the organisms that are fit to thrive and reproduce in that environment grow in number, while those not suited to the environment are less successful at survival and reproduction and become rare or even die out.
In this way, nature “selects” certain traits in the gene pool of an organism. For instance, in a species of moths with varying patterns on their wings, those with wing patterns that camouflage them against their environment more effectively will become more common.
So, could this process not drive evolution? Use some basic critical thinking skills with me for a moment.
1) Natural selection never creates any new genetic information.
In order for a species to evolve into a higher species, it must acquire new genetic material. But natural selection does not introduce even one bit of new genetic information into the gene pool of a species, it simply changes the prevalences of various traits within the gene pool in that specific setting.
Natural selection didn’t create moths with certain wing patterns, or finches with certain sized beaks, it simply made those traits, which were already present in the gene pool to begin with, more common in that area.
I’m sorry if you know your science and find this kind of review condescending. But it amazes me how many young people who subscribe to macroevolution think that natural selection demonstrates it.
2) Genetic limits within species.
Dogs are a great illustration for this point because they have such an amazing degree of genetic variability within their gene pool. Starting with wild dogs and given a few centuries, we have bred them into everything from chihuahuas to great danes and bull mastiffs.
This wasn’t just natural selection. This was guided, intelligent selection on a huge scale. So, if we wanted, could we breed dogs into cheetahs? What about whales? Stupid questions. A dog will always be a dog because there are genetic limits in its DNA. It can only present the morphologies that correspond to its genetics, and all of our breeding introduces no new genetic material.
Once again, we are changing the prevalences and frequencies of genetic information, but we are not creating any of it. Not macroevolution.
3) Natural selection would almost surely work against many of the changes that would have been necessary between species.
If reptiles evolved into birds, explain to me how scales evolved into feathers and arms evolved into wings. Remember that every step we take must be more fit to the animal’s environment that the one before it, or natural processes won’t select it.
Its going to take some very creative thinking to dream up why nature would select an arm/wing-scale/feather hybrid over a fully functioning, elegantly designed normal reptile. Natural selection won’t tolerate those kinds of ridiculous morphological leaps.
The real question is whether or not genetic mutations are capable of introducing new, beneficial genetic information into the genetic makeup of an organism in ways drastic enough to drive evolution. For instance, can a species feasibly change its number of chromosomes? (Chimps have 48, humans have 46) Can we explain the emergence of two distinct, codependent sexes through mutations alone?
These things haven’t been demonstrated satisfactorily for me. And that is where the discussion needs to happen. Mentioning natural selection to me again is not fruitful.
Lampstand 