My first exposure to evolution came through Pokémon. I can recall watching in awe as a creature became enveloped in an aura and morphed into a new monster. It looked something like this:
As you and I both know, this is not how evolution works. Aside from a protein named after Pikachu (Pikachurin), Pokémon does not offer a faithful lesson in biology. While evolution has become required in most classrooms in the US and the rest of the world, many misconceptions about the most established fact in science abound. In this new segment I will address the most common of these misunderstanding. Have any questions of your own? Please suggest them in the comments or message me directly. Enjoy!
Why species, not individuals, evolve
This common question has an easy answer. As defined, evolution is the change in inherited characteristics in a biological population over successive generations. Sound like a mouthful? Put simply, evolution is all about genes.
You, a dust mite, and all other life on Earth contain DNA, the building block of life. DNA consists of molecular sequences, called genes, that determine characteristics such as eye color or blood type. Each time a creature reproduces, it passes its genes to its offspring. For creatures that produce sexually (i.e. humans), each parent contributes half of its genes to the child, while organisms that reproduce asexually make copies of themselves. Note that an organism cannot change its DNA—this unique code is determined solely by one’s parents. The survival of a characteristic depends on which genes are passed on.
Evolution is the process by which these inherited characteristics change in a population. It marks the transformation of a species’ DNA over time as genes are passed on, altered, or phased out. These changes in the gene pool can occur in three ways: natural selection, mutation, and genetic drift. Natural selection, often described as survival of the fittest, is the process by which the characteristics best-suited to an environment become widespread. Mutation occurs when a gene is incorrectly replicated during reproduction, and genetic drift accounts for random inheritance patterns over time. I will go explain more about these in a future post.
It follows from this that only species can evolve because changes in genes occur only during reproduction. Though an individual can learn and adapt to an environment, it cannot alter its DNA. For example, a population of tree moths becoming darker to better evade predators is evolution while a dog learning to come when called is not. This is because the moths’ gene pool has changed while the dog’s has remained the same. Since an individual cannot change its DNA, it cannot evolve. Sorry, Pokémon fans.
Does this make sense? I hope so! Let me know in the comments section below. Be sure to leave any questions you have as well. I will answer them either in the comments or (if they are big enough) in a future post. As always, please like, share, or reblog this post if you enjoy it. That small click really helps me out! Be sure to check me out on Twitter and Facebook as well. Thanks for reading! Don’t forget to subscribe for new content every Wednesday! IT’S FREE!
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Comment question of the week
Does this make sense? What questions do you have about evolution?