“Evolution forged the entirety of sentient life on this planet using only one tool: the mistake”.
The above quote is from Dr Robert Ford, one of the main protagonists in a popular, TV show, Westworld. A simple sentence, but one which sums up evolution and one of the forces behind it quite succinctly. In truth, the quotation applies, not only to sentient live, but to all life on our planet, and if life has evolved elsewhere, and enjoys a healthy competition for resources, then it will probably apply there too.
Each of us is built from a combination of genes that we have received from our parents. Half from our mother, the other half from our father. And so it is with most animals and plants. The genes that define us are written in DNA. Each of our cells has an exact blueprint in DNA, made up of millions of genes, detailing how we are built and operate. DNA is generally quite good at making exact copies of itself and so our genetic information is passed accurately to our children and our children’s children. On occasion, however, errors creep in when DNA makes copies of itself and these mistakes can also passed to our offspring.
Most of the time these mistakes or mutations in our genes are harmless and so pass by unnoticed. Sometimes, they are negative and may cause a disease or a negative trait to express itself. Over the course of time the negative mutations tend to die out because they do not offer any biological advantage to the organism. Occasionally, the mistake is positive and leads to a tangible benefit for the animal or plant. These benefits tend to confer a biological advantage to an organism over its competitors and so will be passed on from generation to generation and eventually spread throughout a population.
The accumulation of these mistakes over time can change a plant or animal significantly. Eventually the sum of all changes will be enough so that a new species will have been created. Over the billions of years of evolution these simple mistakes have allowed life to evolve, adapt, diversify and colonise almost the entirety of our planet. Each and every species that we see today has got here through the accumulation of a multitude of mistakes. Without these mistakes, life as we know it would not have happened.