As we all know, humans evolved from monkeys. But what does that mean? In this article we will be covering evolution and the process of how it works. The three main topics we will be covering are natural selection, multicellular life, and mass extinctions. These topics are part of how evolution is possible, and how it works and are part of the study of Cosmology. Cosmology is the study of how the universe came about, works, and how it is changing. This is based off of the Crash Course Big History playlist on YouTube.
“Natural Selection” means that all the different traits of different living beings all have been chosen naturally. An example is giraffe's long necks that are used to get leaves off of tall trees. Its long neck was chosen to be that way naturally because of evolution's motivation to survive. For example, humans have unusually large brains to make up for our puny bodies, and weak muscles. The selection of these traits is done so with the drive to stay alive, and to reproduce. Knowing that death may be around the corner motivates nature to give us some good traits, like legs! If we just flopped around like fish, it would be very hard to run away from a lion who is trying to eat us.
Long ago, Earth used to be a giant ball of ice. And as you can probably guess, earth was probably not the best place for life. There may have been some organisms that lived off photosynthesis in places with some heat and water… but that was pretty much it. But over time, these individual cells would start working together to create complex multicellular life. The reason why these cells combined is because it would make it easier to survive if they had multiple cells to work with. Multicellular life has gone through five mass extinctions. What we will be focusing on next, is how those mass extinctions worked.
The competition for life is grouped in something called niches. Niches are groups of different animals that get food and reproduce the same way. When there are more multicellular beings in a niche, there is more competition. SPOILER ALERT: Usually all this competition ends in a mass extinction. When there is a mass extinction within a niche, there is barely any competition between species allowing rapid adaptation and then the niche can be quickly filled again. This process keeps repeating in between small niches and large niches. The only reason why there are so many mammals today is because the niche with the dinosaurs got wiped out allowing it to be filled rapidly with mammals somewhat like the ones alive today.
Today we talked about natural selection, multicellular life, and mass extinctions. Natural selection helps biological life improve and become better at surviving and have longer lifetimes. Multicellular life has made it so that there are even beings to evolve. In addition, mass extinctions allow for evolution to fill the empty niches with new and more advanced beings. The evolutionary epic is part of cosmology, the story of the universe, and has brought us here today.