Darwin’s Contribution to the Theory of Evolution
Hey guys! Welcome to the next video in our Biology series on Darwin’s Contribution to the Theory of Evolution.
First, let’s take a look at who Darwin was. Born in 1809, Charles Robert Darwin had a pretty rough start to life. His mother died when he was eight years old, and he despised his classical education at the Anglican Shrewsbury School. He loved science and collected seashells, bugs, rocks, and more. He found his other school assignments, such as Latin memorization and English writing very tedious. His headmaster and his classmates criticized him for his interests in the natural world. In 1825, at the age of 16, his father sent him to Edinburgh University to study medicine. Darwin found Edinburgh to be an outlet for him to exercise his scientific interests. He joined a club called the Plinian Society which consisted of like-minded students fascinated by scientific philosophy and practice. Their meetings consisted of reading research, discussing findings, and small countryside walks to observe natural phenomena. Darwin was later mentored by Robert Edmond Grant a radical pioneer in evolutionary theory. As Darwin learned and studied under Grant, he grew a desire to go even further into the study of evolution as he studied invertebrate zoology, and, because he could not stand the sight of blood, he ended his studies in medicine.
Darwin’s father arranged for him to attend Christ’s College, hoping his son would join the priesthood afterward. After his graduation, however, Darwin accepted an opportunity to sail to South America as a resident biologist aboard the HMS Beagle. The voyage lasted longer than expected (five years!), and circumnavigated the globe (sorry flat-earthers). It’s what Darwin learned and hypothesized while on the Beagle that most consider to be his great contribution to modern science.
What is the theory of evolution, and what did Darwin contribute?
I’m glad you asked! Evolution, within Biology, can be defined as the change of characteristics of a species over a long period of time, and Charles Darwin would add that this happens by the process of natural selection.
So, if natural selection is Darwin’s contribution to the theory of evolution, what is it exactly?
Within a species, certain individuals will display different physical characteristics or phenotypes. These differences are due to variations within their genes. Well, this theory of natural selection would say that, because some of these characteristics would make certain individuals more prone to thrive or survive within their specific environment that these individuals are also more likely to procreate and pass along their genes to their offspring. Of course, on the other side of that, the individuals who possess the traits or characteristics that make them less inclined to live and therefore less inclined to reproduce, then they will not pass their genes down to their offspring.
Darwin offered a more complete explanation in his book, “On the Origin of Species by Means of Natural Selection,” along with four conditions that must exist for natural selection to work:
- During reproduction, more offspring will be viable than will die.
- Specific traits and characteristics can be passed from parents to offspring through reproduction.
- There must be variation in each organism’s fitness which will relate to their heritable characteristics.
- There is a variation within any population of the same species and is naturally inherited from the organisms most likely to survive.
If that was kind of confusing, no worries, we can break it down together. First, obviously a species must have a higher birth rate than death rate, otherwise, the entire species could die out within a couple generations. Second, an organism, whether it’s a fish, plant, or even you, must get genetic information from someplace, in order to live, and for living creatures, it comes through genes passed down to us from our parents. Those traits help you live and survive. It’s also what makes you have facial features or hair and eye colors like that of your parents. Third, every organism, even you and I, are genetically predisposed to certain activities or survival situations. Imagine a moth that was bright red flying through a green forest… that little guy may not last as long as a green moth, or at least a brown one that can hide against the bark… because predators may be able to spot the red one more quickly. Which leads us to: Fourth, the creatures that survive pass those unique genes onto their offspring and therefore the variations in the gene pool that benefit the species are passed along.
And that is Natural Selection, which Darwin added to the theory of evolution!
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