1. Variation: Individuals within a population exhibit variations in their traits, whether it's size, color, speed, or any other characteristic. This variation is largely due to genetic differences.
2. Heredity: These variations, at least to some extent, are heritable, meaning they can be passed down from parents to offspring.
3. Struggle for Existence: Organisms produce more offspring than can survive, leading to competition for resources like food, shelter, and mates. This is known as the "struggle for existence."
4. Differential Survival and Reproduction: Individuals with traits that make them better suited to their environment (i.e., those who are better at surviving and reproducing) are more likely to survive and pass on their advantageous traits to their offspring. This is the core of natural selection.
5. Gradual Change: Over many generations, the frequency of advantageous traits increases within a population, while less favorable traits decrease. This leads to gradual changes in the population's overall characteristics, ultimately potentially resulting in the emergence of new species.
In summary, natural selection acts on variations that are already present within a population, favoring those that are better adapted to the environment and allowing them to reproduce more successfully. This process leads to gradual changes in the population's characteristics over time, ultimately contributing to the evolution of new species.
