Quick Explanation of Natural Selection (for Deepak Chopra)

Click here for Deepak Chopra's attack on The God Delusion by Richard Dawkins.

Have you ever heard that evolution is a theory of chance? That's a (big) misunderstanding that many people, including Deepak, make. Or have your heard that there must be a God who made everything because you can't have all this order on earth by chance. Well that's true, it can't be here all by chance. How about how an eye is too complex to have evolved? The theory of evolution by natural selection is an elegant and powerful explanation of how we are all here - with eyes - non randomly and with no magic.

"Life results from the non-random survival of randomly varying replicators." Richard Dawkins

Let me unpack that a little for you.

For evolution to occur three factors are required.
1. variation.
2. selection.
3. hereditary.

1. Variation.
Variation is generated randomly by mutation. This is where people get (perhaps understandably) confused. People think evolution is just about the mutation. Mutation can only explain simple changes. Something zigs instead of zags. But that's not the whole story.

2. Selection.
example of how the environment can non-randomly select for and against a property. ImagineSelection is non-random. The environment does the selection. A very simple non-biological you have a bag of flour that has several cups of sand randomly distributed in it. How do you separate the sand and the flour into two separate piles? One way would be to use a sieve. A sieve lets through matter (flour for example) that is small enough to fit through the holes in the mesh. It prevents matter that is in chunks larger than the holes passing through the holes. After sifting, you have separated the flour from the sand and have two highly ordered, non random piles.

3. Hereditary.

I won't go into why Dawkins uses the word Replicator, though I think it is an excellent term. Do some research and I'm sure you will agree. I recommend Susan Blackmore's 'The Meme Machine' for an excellent introduction the General Replicator Theory.

The Hereditary principle is just as important as the principle of variation and selection. You really can't understand any of the three principles without seeing how they work together. The Hereditary principle explains how non-randomly selected single mutations can ACCUMULATE over time. This concept of accumulation is really key. Billions of years of accumulating the randomly produced but non-randomly selected good changes in the recipe that develops an organism from a zygote leads to marvels such as you and me (and the rest of our cousins in the biosphere).

I hope this has been helpful :)

Images from
http://taxonomy.zoology.gla.ac.uk/~rdmp1c/teaching/L1/Evolution/l2/eye.html