What are the key principles of Darwin's theory of natural selection?

Darwin's theory of natural selection is based on variation, inheritance, high rate of population growth, and survival of the fittest.

Charles Darwin's theory of natural selection, also known as Darwinism, is a fundamental concept in biology. It explains the process by which species evolve over time through changes in their inherited characteristics. The theory is built on four key principles: variation, inheritance, high rate of population growth, and survival of the fittest.

The first principle, variation, refers to the differences in physical traits among individuals within a population. These variations can be as simple as eye colour or as complex as resistance to a disease. Darwin proposed that these variations are not random, but are influenced by the environment in which the species live.

The second principle, inheritance, is the process by which these variations are passed on from parents to offspring. Darwin suggested that those traits that are beneficial for survival are more likely to be inherited by the next generation. This is because individuals with these traits are more likely to survive and reproduce.

The third principle, high rate of population growth, suggests that most species produce more offspring than can survive. This leads to a struggle for resources, such as food and space, resulting in competition between individuals.

The final principle, survival of the fittest, is perhaps the most well-known. This principle suggests that those individuals with traits that give them an advantage in their environment are more likely to survive and reproduce. Over time, these advantageous traits become more common in the population, leading to evolution.

In summary, Darwin's theory of natural selection explains how species evolve over time. It suggests that individuals with advantageous traits are more likely to survive and reproduce, leading to these traits becoming more common in the population. This process of 'natural selection' is what drives evolution.