Charles Darwin's Explanation Of Natural Selection

Discussion for Chapter Four: Genetics and Evolution
Fitness is measured by the ability of an organism to survive and reproduce in an environment. Charles Darwin’s explanation of natural selection involves three principles. The first principle is variation which states that every species is composed of a great variety of individuals. Some of these individuals have adapted to their environment than others have. The second principle of natural selection is heritability. This is where offspring inherit traits from their parents in some degree or another. The third principle is differential reproductive success which is where better adapted individuals produce more offspring over the generations than poorer- adapted individuals. The frequency of adaptive traits gradually increases in subsequent generation.
Disadvantageous or maladaptive traits will generally decline in frequency. They do not disappear completely because some traits are linked to others that might have advantages that outweigh the disadvantages. Natural selection does not account for all variation in the frequencies of traits. All in all disadvantageous and maladaptive traits will not disappear because the benefits must
Human populations that live in arctic climates tend to be bigger and more robust because it helps them stay warm in harsher environments than warmer environments. In the tropical climates human populations tend to be smaller and skinny because it helps them stay cooler. Also the body parts in arctic climates are shorter than those who live in warmer climates whose body parts are longer and limber. Those who live in warmer climates tend to have more melanin in their skin which makes their skin darker to protect them from the sun and from tropical diseases. Human populations adapt to what environmental conditions they inhabit and they grow to adjust to those