Charles Darwin was an English naturalist whose ideas revolutionized Biology. He is considered the father of evolution and created the theory of natural selection. In this theory, he had five key points.
More offspring are produced than survive
This idea states when offspring are created, there will not be a 100% success rate. Only the offspring with favorable traits will be able to survive. In every environment, there are limited resources such as food and water. Other factors such as disease and predators will also affect offspring. Therefore, species may need to produce more offspring to compensate for the loss or protect their children. Both sides of this spectrum are seen in the wild. For example, starfish lay 2.5 million eggs. However, only a small percentage survive and reproduce. Elephants, on the other hand, have a significantly slower reproduction rate. One pregnancy period may last 22 months. To make sure these babies survive, the mothers take care of the children for 16 years, the longest in the animal world.
All populations of species have variation.
Regardless of what species, there will always be variations. This starts with allele mutation in the genes of a species. An example of variations in color, size, diseases immunity, and others. Some variations may be better than others. For example, when there is a mutation for a bird to have a bulky beak. If they need to crush large nuts, it would help them. However, if they need to catch small grubs, it would harm them. It is important to remember that nature selects the adaptations or variations that are helpful to the species.
Competition
When variations or mutations occur, competition is affected. In environments, there are limited amounts of food and water as well as diseases and predators. This means all animals will have to obtain the food before their competitors or escape a predator. The variations will mean that animals in a species will have an advantage or disadvantage. For example, if a shark gets a mutation that allows them to smell exponentially better, it will be able to get to its food and survive. Another example is if there is a virus or parasite (such as COVID-19), the immune animals will be able to survive. The ones that are not immune will die and not be able to continue their generation.
“Survival with the fittest”
The meaning of “survival of the fittest'' has been misinterpreted by many people. To start with, “fitness” in biology does not relate to size or physical strength. The fitness of an animal is based on how likely they are to survive in the wild and continue to reproduce. Therefore, the phrase, “survival of the fittest” means the animals that have the most beneficial adaptations will survive to reproduce. These adaptations are created from the mutations or variations in animals, mentioned in the second point.
Descent with Modification
The idea of descent of modification means species will change over time as generations pass. It wraps up and summarizes all the points prior. An example of descent with modification is humans. When the first species of humans were born, they lived near the equator in Africa. Due to this, a large majority of the humans had large amounts of Melanin. Melanin is the pigment that leads to dark skin. Melanin also protects your skin to a certain extent from sun rays. This means, close to all humans at the time had dark skin. However, as humans moved away from the equator, there was no need for dark skin. The human population grew, and the variety of skin colors did as well. As generations passed, humans had different skin colors, and there were modifications.
Understanding evolution is a salient concept. It helps people appreciate everything around them and gives them a new perspective. People tend to value things significantly more when they fully understand it.
https://www.chesapeakebay.net/S=0/fieldguide/critter/common_sea_star
https://www.nationalgeographic.org/encyclopedia/charles-darwin/
https://www.smithsonianmag.com/science-nature/the-evolution-of-charles-darwin-110234034/
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