In the year 1859, English biologist Charles Darwin published his book On Origin of the Species, the first ever book that suggested that there existed a theory called Natural Selection. Natural Selection is the process in which individuals can adapt and change to their environments over different generations as a result of them passing on certain traits. (1)
History of Natural Selection
In 1831, Charles Darwin was offered a chance to embark on a five-year-long voyage on a ship called the HMS Beagle. On that voyage, Darwin saw the world far and wide, allowing him to study different species in various areas. While on his voyage, Darwin suspected that an environment can actually manipulate species, causing them to change over time. (2)
On his second trip aboard the HMS Beagle, Darwin noticed that bird populations grew exponentially while food grew arithmetically. This meant that there was a limited amount of food for the exponential number of birds living in that same area. Darwin concluded that the limited amount of food would impact different demographics of birds, leading to a struggle for survival amongst them all. However, once he had this idea, he wanted to have some evidence to back it up before he published it.
Darwin found evidence for his theory through artificial selection, in which he bred pigeons to have offspring with exaggerated features. Since the pigeons tended to pass off different traits to their offspring, Darwin had some concrete evidence of his natural selection theory. Eventually, he published his book, On the Origin of Species, and it shook the scientific world. (3)
How Does it Work?
The idea of natural selection is that there are a variety of different traits in different individuals in a species. However, because of environmental pressures, some species with specific traits will be unable to reproduce to their full extent anymore. For example, if there is a species of spiders that either come in colors brown or white, the brown ones will be more successful in reproducing since they can blend in with their environment better. White spiders will die off and, as a result, reproduce less due to them being more visible to predators. As a result, only the brown spiders will reproduce more, making them the more advantageous trait. Eventually, all spiders of that species will be brown in color unless some other environmental pressure comes along. (4)
How Does it Relate to Evolution? While natural selection applies to the traits of one species, it can also relate to a species as a whole. If one species isn't fit to survive in an environment, it can result in them evolving into a different species.
Controversy
Natural Selection was considered a very controversial theory for a variety of different reasons:
Lack of Evidence: Darwin didn't have enough evidence to back this theory up entirely. He had a lot of evidence from his travels, but most of the evidence that makes up the theory today requires a lot from the geology and paleontology fields, which were not as advanced back in Darwin's time.
Religion: Many religious people at the time held beliefs that conflicted with Darwin's theory. It basically challenged the idea of divine creation, which is a core belief in many religions, leading many people to be displeased with his findings.
Lack of Scientific Understanding: During Darwin's time, many of the scientific fields that play a role in natural selection were very underdeveloped, specifically genetics, which plays a huge role in understanding natural selection.
Other Theories: Many scientists preferred Lamarck's theory of inheritance since it was more reasonable at the time. (5)
Why Does it Matter Now?
Natural Selection is still happening to this very day, including humans. If you compared the human species to what we were around 200 years ago, you could see that there were certain traits being passed on to give us a better chance of surviving. It's also very present in other species. (6)
One species in particular is the Cypripedium orchid flowers. This genus of orchids has a very low sexual reproduction success rate, forcing them to rely on reproduction through cloning. Because a majority of these orchids simply clone themselves, there is little genetic variation throughout the species. If there's little variation, if environmental pressure affects them in any way, they will all go extinct because they're all essentially the same. We can utilize our knowledge of natural selection and discover ways to help species like these to have a more diverse population.
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