My dear daughter,
Let’s learn about natural selection!
Up until the XIX century no one was really sure where species came from. Some believed they appeared out of thin air, others believed the modern species were always here and there were no prior species, and many relied on religion, especially christianism, and took what the Bible said for granted – that god had created the world some 6,000 years ago and created all the species that we see today in a couple of days.
Scientists and philosophers had already been thinking seriously about it for some time. They knew fossils of extinct species, geologists already knew the world was a lot older than 6,000 years. A concept of mutation and adaptation already existed.
After many voyages and observations around the world, Charles Darwin published the book “On The Origin of Species” in 1859. You can find a copy on our bookshelf.
What Darwin proposed was in fact an algorithm, a natural algorithm, so simple and elegant it is irrefutable after all these years. It doesn’t require a will or intelligence or a creator. It’s natural selection.
There is a popular concept of evolution which is very wrong and misleading. Many people don’t really understand or don’t want to understand natural selection. I will try to explain why in the future.
Here’s the basics: every species on the planet reproduces. Some more than others, but there’s a lot of reproduction going on all the time. Even in the most simple organisms, composed of a single cell, which usually reproduce by making exact copies, it’s a complex process and there are some random events at play.
If you take any large enough set of reproductions, at some point something will not happen as planned. The genetic material inside the cells contain precise instructions, but sometimes they are not followed to the letter and some random error occurs. That’s where mutations come into play. You can say life itself is the result of random error in some process. We will clarify this concept in another opportunity.
Mutations are not intrinsically good or bad, they just happen. Now, every individual lives in an environment, they feed in the environment and reproduce in the environment. They interact with each other, with other species and with environmental variables.
Sometimes a mutation will render an individual more likely to survive in its environment, or to survive longer. Maybe because it becomes easier for it to feed, or it has access to a new source of nutrition. Or it becomes more skilled at avoiding predators or competitors. Or it becomes more attractive to females if we’re talking about a species with sexual reproduction and two genders.
Anyway, this individual fares better and it has a better chance of leaving descendants. If he passes on that mutation to the descendants, they will also be more likely to leave more descendants of their own, with that specific mutation or set of mutations. There will be more individuals with the mutation and it will become harder for individuals without the mutation to beget the same number of offspring. In time, chances are individuals without the mutation will disappear.
When enough mutations accumulate, a new species is born. They will be so different from their ancestors it will be impossible for them to mate and have fertile offspring.
This will almost certainly happen when two populations of the same species get separated through some geologic process and start developing in two different environments. I’m sure you can already tell why, considering what I have just exposed.
Therefore, evolution is driven by random mutation and environmental selection. It’s a completely natural process and it dispenses any third of exterior factor, intelligence or divine will. It is happening all the time in organisms. Cells are always dividing and multiplying, provided they have a source of nutrition. Every cell division presents several chances of mutation.
Evolution doesn’t mean improvement, not always. It means better adapted to an environment. And individuals don’t develop new characteristics out of the blue to instantly respond to a new environmental hazard they have been exposed to, no matter how frequent.
Sometimes evolution reaches the same results by different paths, like the development of eyes in mammals and octopuses. Sometimes it takes a step back, as with aquatic mammals such as whales and dolphins. It’s all so very interesting.
When people say all humans descend from apes or monkeys, they’re wrong. Modern humans, modern apes and modern monkeys all descend from a common ancestor. That is why not all modern apes have evolved to become humans. They have evolved to become chimpanzees, gorillas or bonobos. They continue to evolve, even though humans have now messed up every single environment on Earth.
Also notice natural selection is not a theory of the beginning of life, it is a theory of evolution. It’s evolution by natural selection. To explain the origin of life, we have abiogenesis, or how organic and inorganic matter combined randomly to produce living, self-replicating beings.
Love,
Dad
Aspergers Dad 