The Theory of Evolution by Natural Selection

06/12/2010 § 1 Comment

Today’s class was almost like a flashback to eighth grade science with Ms. Jewett. Our topic of the day was Charles Darwin or Charlie Darwin. In the scientific world, Charles Darwin played a crucial role in helping man move forward to understand how human life and—generally—life on earth evolved and how it currently evolves.

However, Charles Darwin was not exactly the “Father of Evolution” just yet. Many other scientists, philosophers, and other experts way before Darwin also pondered the phenomenon of evolution. Such kind of people including Lucretius, a Roman philosopher who lived about 2000 years ago, Plato, a Greek philosopher who lived more than 2000 years ago, and Charles Lyell, whose book Principles of Geology was a source of information Darwin used during his voyage around the world. So, Darwin wasn’t the only one who thought about how animals evolved and how living creatures turned into what they are now; he simply suggested a new theory of evolution that scientists would later find out would be the most accurate idea.

The first of Darwin’s ideas that we gathered from class included:

Over-reproduction. This idea stated that some species produced more young than would survive to adulthood. Basically, the young would die before they could make any offspring.
Variation. This idea showed that individuals in a species were different from each other in many factors. Even brothers and sisters differed, which is quite true to this day, I would know. With this idea, Darwin thought that some variations in different individuals were preferred during certain conditions while others did not suit the current condition of the time.
Competition. It was and is a big part of evolution. On this planet we live on, earth holds only so much food to feed the mouths of the animals that live on it. Sure, the animals eat one another all the time—even humans, but that supply is also limited and can only last for so long. Therefore, species and individual organisms will compete to last the longest with the food that is available. Those who win; their prize is food. Those who lose; obviously get nothing.
Survival of the Fittest Phenotype: This idea related to natural selection. Organisms that held phenotypes that suit the conditions of the generation and stood strong during that era or period of time would get to survive and pass on their genes to the next generation. These genes get passed on because they were successful in one round of Evolution; they may be useful in the next.
Favorable Combinations Increase: This idea also connected greatly to the concept of natural selection. Generations tended to have more individuals who hold successful and favorable characteristics. In the previous generation, the individuals whose genes were not successful died off and didn’t pass to get to the next round.

(I’ve been thinking of competition and natural selection and looking at the whole idea of evolution as a game with deadly or dangerous rounds. If a species (player) doesn’t succeed in the round, they kind of just die off. No extra lives in this game.)

Darwin began thinking that evolution looked like a tree. The trunk was everyone’s—every single living thing’s—common ancestor. There were branches and twigs that represented all species. Some branches died—and maybe even broke off the tree—while the others grew stronger or stayed the same—they survived a few generations. As far as I know, this was the first time someone had thought of evolution in the form of a tree.

Overall, one of the biggest ideas of today’s class was based on the fact that all animals cannot survive. As mentioned above, there is competition between all the animals for the limited food and sources of shelter found on the earth. For all organisms—including humans, only the right adaptations will keep them alive. So, basically, so far, we, along with millions of other species, have been lucky so far to survive this round of Evolution.

§ One Response to The Theory of Evolution by Natural Selection

  • Dave Ferguson says:

    Kari,

    Good job of defining natural selection, and also of putting Darwin into a historical context. Also, I like your final paragraph which examines one of the implications of natural selection.

    Mr. F.

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