Natural Selection

Traits are characteristics that things have such as hair color, eye color, and foot length.

Living things get their traits from their parents, but traits can also come from other places. For example, a person can be born with brown hair but can artificially change it to purple if they choose.

Natural selection is when an organism lives because of its traits or something it can do better than other organisms of the same kind. For example, slower animals usually get caught.

Humans can affect traits of other things by mixing them together. For example, I have a Pomsky dog, which is a Pomeranian and a Husky mixed together.

If an animal is the same color as its environment, it blends in better and can hide. This can help an animal hide from predators or hide to capture prey.

If an animal with the same trait is always caught, it cannot have babies. So eventually, no more animals in that population would have that trait.

Trait variation is when organisms in a population have differences in the traits they have. For example, the giraffes have long necks, but not all their necks are the same length.

A change in the environment can affect an animal’s ability to hide from a predator. For example, we saw that when the environment changed, the hawk ate the light-colored pocket mouse instead of the dark one because light one was easier to see.

Natural selection is a process in which some living things survive better in their environment and are able to reproduce and pass on their genes.

Artificial selection is a process in which humans choose what traits they want other organisms to have.

Natural selection can lead to evolution of a population because if an organism doesn’t survive, it cannot reproduce and pass on its traits. If traits are not passed on, then they eventually go away—like what happened to giraffes with short necks.

One way natural selection could affect humans is when bacteria that can make us sick changes. For example, the bacteria we saw in the video has changed to become resistant to the medicine that used to kill it.