Bare Bones Biology 012

If you see me sitting in my car way out at the end of the driveway on a Sunday morning at 6:55, you will know I’m trying to listen to Bare Bones Biology to make sure I post the correct transcript. And here it is.

Evolution. How it Does Work

It will not surprise you to hear that the nose of a pug dog is different from the nose of a greyhound. Those traits are known as phenotypes. In fact all inherited traits are known as phenotypes, and these particular ones are caused by differences in the gene pools of pugs compared with greyhounds. The shared gene pool of Chihuahua dogs does not include genes for large size, while the shared gene pool of St. Bernard dogs — does. Those are also phenotypes. The behaviors of a normal Poodle and of my Catahoula Hound are very similar because they are both dogs with all the common traits of dogs. But some Poodle behaviors are quite different from the innate chasing and killing instinct that is bred into most hunting hounds. These behaviors are also phenotypes. The phenotype is the physical expression of the genotype.

These differences among the dogs did not happen by magic. They are the result of human selection over many generations. They happen because humans in the past chose which of the many pups born in a generation were able to pass on their genes to the next generation. That’s known as selection. Certain dogs were selected for reproduction. And so by selection, we humans changed the gene pools of the different breeds of dogs, and when the gene pools were changed the phenotypes changed.

We humans should not get big heads over this. We have not and can not change the laws of nature. What we did was to learn how the natural law works and we used it to make domestic animals that suit our needs. Humans used the natural law of selection to change the gene pools of domestic animals.

Biological evolution is a change in the gene pool over time as a result of selection. At its most basic it is just that simple. A change in the gene pool as a result of selection, only in the case of nature it’s natural selection rather than human selection. It is not survival of the fittest according to how humans imagine fitness. It is the successful transmission of genes to the next generation by those individuals who best fit into the balance of nature. So there is no point arguing about this aspect of evolution, because there are many, many proofs, both in domestic animals and in nature.

Evolution is happening all around us, all the time. Living things, to stay alive, must constantly interact with the changing realities of life, or they wouldn’t stay alive very long. Humans must adjust to change to stay alive. We must be able to come in out of the cold and find our food. Our digestive system needs to know how to respond if we eat a loaf of bread or an omelet. We have to breath. Our living bodies can do all this because of our genes. All the genes in our bodies, that is our genomes, working together in response to the conditions of life.

The requirements of life are fundamentally the same at all the levels of life. The information for a cell to survive comes from the genes in the cell turning on and off so they change the phenotype of the cell in response to conditions in its environment.

The information for you to survive depends on the behaviors of your genes as they turn on or off at the right time and place in your body, making proteins when and where they are needed, so your nervous system can react to the hot stove and your digestive system can respond to the first sweet wild plums of June that we picked yesterday. Your genes turning on and off make it possible for you to respond to your environment and therefore stay alive.

The information for the ecosystem to stay alive comes from the gene pools of all the organisms that that live in the ecosystem and change over time in response to their environments. Changes in the gene pools over time is evolution. If there were no evolution there would be no life on earth because evolution is the process by which he ecosystem is able to respond to change and therefore stay alive.

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