Understanding evolution
- Organisms are adapted to live efficiently in their environment. For example, fishes can breath underwater while cats cannot: fishes are adapted to life in water.
- Inside a species there can be variation in one trait, meaning that the trait is slightly different from one organism to another. For example, the peppered moth is a butterfly that can have wings either dominantly white or black, which allow them to hide on trees.
- Changes in the environment means that different traits become more adapted than others. For example, in forests with most trees having dark trunks, the black version of the peppered moth survives better, and vice-versa.
- The change of a proportion of a trait is called evolution. It is thus populations that evolve (individuals never evolve!).
- If the same species live in different environments, then they will eventually evolve into different species. This diversity in environments and the variation in traits is at the origin of diversity in the living world. For example, the peppered moth can eventually evolve into a black species and a white species, depending on the color of the trunks of the trees.
