Charles Darwin's Theory Of Natural Selection

Evolution is the change in the heritable characteristics of biological populations over successive generations. Evolution is based on the idea that all species are related and gradually change over time. The theories that Charles Darwin presented are the basis of modern explanations of evolution. Darwin used the phrase descent with modification to explain that all species had descended from only one or a few original kinds of life. He also presented the theory of natural selection. He had four main parts of his theory of evolution by natural selection: overproduction, genetic variation, struggle to survive, and differential reproduction. He believed that more individuals are produced in each generation that can survive, phenotypic variation

He also used the expression “survival of the fittest” to describe natural selection and how species adapt and change by natural selection and the best adjusted mutations become the most dominant. Darwin’s ideas of natural selection show that natural selection is the mechanism of evolution. His theories were the core of evolution as we know it today.

A mutation is an alteration in the nucleotide-base sequence of a gene or DNA molecules. Mutations can produce variation in the body shape and function of the creature who inherits the modified DNA. Mutations can either happen in the germ-cells, which is the gametes, or in the somatic-cell, which are body cells. Some mutations are lethal and may result in death. Examples of diseases caused by lethal alleles are cystic fibrosis, sickle-cell anemia, and Tay-Sachs disease. Mutations can happen in chromosomes or in the gene. Some mutations are actually beneficial to an individual. Chromosome

The ancestors of whales were originally land animals, like humans. The last land ancestor of the whale was the Indohyus. They only went in the water for a small amount of time before having to come up to breath air into their lungs. They usually went into the water to get food because there was an abundance of food in the water. One whale had a mutation that made its nose a little further up on its body. Instead of its nose on its face, the nose was now on the top of it’s head. This is now known as the blowhole of the whale and it allows the whales to stay under the water longer and more efficiently. The whale now had an advantage because they could get more food than the other whales. When the whale reproduced, the population of the whales that were able to get all the food from the ocean. They had an advantage and because of their advantage, they were able to survive. This mutation is one of the many mutations that led to the evolution of the Indohyus to the whale as we know it