What is the probability of creating a fully developed animal or a human being? Creationists often use this argument to challenge science, but that is understandable. What is depressing is to see many scientists, too, falling into their trap.
Look at this mind-boggling probability. Think about one biological molecule in our body – haemoglobin. The molecule consists of 4 chains of amino acids, and each chain is about 146 links consisting of a possible 20 amino acids. So, to get a functional molecule, it needs to get one right out of (20)146 options. How is it then possible to have the whole human body created? Since your random processes can’t explain such ‘beautiful crafts’ of nature, you better accept my design theory!
It is a valid question, except that today’s complex systems are not formed like this. The answer lies in evolution. You and I are today because of the accumulated small changes. Not from any single change. Getting a small change is relatively easy, with about a few million unforced errors happening every day.
The complex systems we see today all originated from simpler systems. And those simpler ones, from even simpler ancestors. Until the stage, when the first life, some RNA-based self-replicating molecule, was formed! And how are they made? By chance in the chemistry laboratory of the earth using simple gases in the presence of heating, cooling and lightning. Stanley Lloyd Miller and Harold Clayton Urey proved that in 1953 by using methane, ammonia, water, hydrogen, and electric discharge to produce amino acids. Subsequent works of scientists synthesised the building bases of RNA from simple molecules.
In my post on SLC24A5 or the one on plant breeding, we have seen that a simple change in a random gene location can produce wonders. Think about it. There have been 3.5 billion years passed since the first life. Millions of trivial changes happened, a few of them passed through the sieves of nature, and a number of them got rejected to extinction. It is called natural selection.
Richard Dawkins: The Blind Watchmaker
Blind Watch Maker
Stanley L Miller, A production of Amino Acids Under Possible Primitive Earth Conditions, Science, 1953
Formation of nucleobases in a Miller–Urey reducing atmosphere, PNAS, 2017
