* Natural Selection Favors Beneficial Variations: Natural selection is the process where individuals with traits that make them better suited to their environment are more likely to survive and reproduce. This means that beneficial variations are passed on to future generations, increasing their frequency in the population.
* Harmful Variations Are Less Likely to Be Passed On: Individuals with harmful variations are less likely to survive and reproduce successfully. This means these variations are less likely to be passed on, decreasing their frequency in the population.
Think of it this way:
Imagine a population of rabbits living in a forest. Some rabbits have thick fur that helps them survive cold winters, while others have thin fur. In a harsh winter, rabbits with thin fur are more likely to die from the cold. The rabbits with thick fur are more likely to survive and reproduce, passing on their thick fur gene to their offspring. Over time, the population will have a higher proportion of rabbits with thick fur, as the trait that is advantageous for survival is selected for.
Important Notes:
* Mutations Are Random: It's important to remember that mutations, which are the source of new variations, occur randomly. Some mutations are beneficial, some are harmful, and most are neutral.
* Evolution is Not Goal-Oriented: Evolution doesn't have a goal or a "perfect" outcome. It simply reflects the changes in a population over time as individuals with traits best suited for their environment are more likely to survive and reproduce.
So, instead of harmful variations accumulating, natural selection actually removes harmful variations from the population, leading to the gradual increase of beneficial traits.
