* Evolution is a change in the genetic makeup of a population over time. It's about the frequency of different genes within a group of organisms, not changes within a single organism's lifetime.
* Individuals don't evolve, populations do. A single organism might develop adaptations or changes during its life (like getting a tan), but these changes aren't passed on genetically to its offspring.
* Evolutionary changes are driven by natural selection. This process favors individuals with traits that help them survive and reproduce more successfully in their environment. Over generations, these advantageous traits become more common in the population, leading to evolutionary change.
Think of it like this: Imagine a population of butterflies. Some butterflies have a camouflage pattern that helps them hide from predators. Others have a more noticeable pattern. If the environment changes and camouflage is more advantageous, the butterflies with the camouflaged pattern are more likely to survive and reproduce. Over time, the camouflaged trait will become more common in the population, leading to evolution.
In short: Evolution happens at the population level through the changes in gene frequencies over generations. Individual organisms don't evolve, they simply exist within a changing population.
