Evolution: Understanding the Debate

This is a topic that has been rehashed millions of times on the internet and I’ve never really felt the need to actually add a drop of my own to the very stormy sea, but it just struck me that I’ve never actually seen a place where you see all the basic definitions in one place. Of course, they’re all out there somewhere… I’m just collecting them together. Disclaimer: This list is by no means exhaustive, it’s just a good place to start if you’re curious.

  1. Evolution – In biology, evolution is the process of change in the inherited traits of a population of organisms from one generation to the next. Though changes between generations are relatively minor, differences accumulate with each subsequent generation and can, over time, cause substantial changes in the organisms. Inherited traits come from the genes that are passed on to offspring during reproduction.
  2. Intelligent Design Intelligent design is the assertion that “certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection.”It is a modern form of the traditional teleological argument for the existence of God, modified to avoid specifying the nature or identity of the designer as a method to avoid scrutiny from the courts.
  3. Natural Selection Natural selection is the process by which favorable heritable traits become more common in successive generations of a population of reproducing organisms, and unfavorable heritable traits become less common. Natural selection acts on the phenotype, or the observable characteristics of an organism, such that individuals with favorable phenotypes are more likely to survive and reproduce than those with less favorable phenotypes.
  4. Universal common descent – Universal common descent is the hypothesis that all living, terrestrial organisms are genealogically related. All existing species originated gradually by biological, reproductive processes on a geological timescale. Modern organisms are the genetic descendants of one original species or communal gene pool.
  5. Irreducible complexity – This refers to the concept of a single system which is composed of several well-matched interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. This is an argument from the ID side to prove that some subsystems could not have been added gradually but should have been “designed” and added whole, as otherwise they would not have been useful. The major (and accepted) critical objections are that something that would be merely advantageous at first could evolve to something necessary as systems that interact with it also evolve, and that there could be “scaffolding” to hold up an apparently complex system until it becomes whole.
  6. CreationismCreationism is a religious belief ( as opposed to ID, which is pseudo scientific) that humanity, life, the Earth, and the universe were created in their original form by a deity (often the Abrahamic God of Judaism, Christianity and Islam) or deities, whose existence is presupposed.
  7. Genetic drift – In population genetics, genetic drift (or more precisely allelic drift) is the evolutionary process of change in the allele frequencies (or gene frequencies) of a population from one generation to the next due to the phenomena of probability in which purely chance events determine which alleles (variants of a gene) within a reproductive population will be carried forward while others disappear. It is distinct from natural selection.Genetic drift and natural selection do not act in isolation; both forces are always at play in a population. However, the degree to which alleles are affected by drift and selection varies according to population size.( Small population–>drift is more important whereas..etc)
  8. Teleological Argument – A teleological argument, or argument from design, is an argument for the existence of God or a creator based on perceived evidence of order, purpose, design, or direction—or some combination of these—in nature. The word “teleological” is derived from the Greek word telos, meaning end or purpose. Teleology is the supposition that there is purpose or directive principle in the works and processes of nature.
I know this is still not very simple for anyone who doesn’t have much experience with science, but the basic arguments aren’t really that complex. Creationism says God created the earth. Intelligent Design tries to prove it by using concepts such as irreducible complexity and the teleological argument, but fails. Evolution says that living things change in order to survive, and we are all the result of billions of years worth of such changes on basic unicellular organisms. Genes are the units of evolution, and natural selection is its mechanism. Genetic drift is another mechanism of evolution that explains the few aberrations in the theory. Forgive me if I sound “biased”: I am. There really isn’t much scope for neutrality here.
Finally, here’s something you should probably keep in mind:

“… there are many reasons why you might not understand [an explanation of a scientific theory] … Finally, there is this possibility: after I tell you something, you just can’t believe it. You can’t accept it. You don’t like it. A little screen comes down and you don’t listen anymore. I’m going to describe to you how Nature is – and if you don’t like it, that’s going to get in the way of your understanding it. It’s a problem that [scientists] have learned to deal with: They’ve learned to realize that whether they like a theory or they don’t like a theory is not the essential question. Rather, it is whether or not the theory gives predictions that agree with experiment. It is not a question of whether a theory is philosophically delightful, or easy to understand, or perfectly reasonable from the point of view of common sense. [A scientific theory] describes Nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you can accept Nature as She is – absurd.

I’m going to have fun telling you about this absurdity, because I find it delightful. Please don’t turn yourself off because you can’t believe Nature is so strange. Just hear me all out, and I hope you’ll be as delighted as I am when we’re through. ”

– Richard P. Feynman (1918-1988),
from the introductory lecture on quantum mechanics reproduced in QED: The Strange Theory of Light and Matter (Feynman 1985).

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