7.3 | Natural Selection

A change to an organism's appearance

A change to an organism's behaviour

A change to an organism's genetic material

By natural selection

By Radiation

By Variation

Changes in the environment

Mutation

Isolation

Less well-adapted individuals cannot reproduce

Most well-adapted individuals can reproduce

Reproduction involves passing on genes

Those that make an organism more likely to survive and reproduce

Those that are present in all the organisms in a population

Those that are the result of the genes an organism possesses

The organism can change to help it survive and reproduce in its environment

The organism has characteristics that help it to survive and reproduce in its environment

The organism is unable to survive and reproduce in its environment

A giraffe increasing its neck length by stretching to reach the top of a tree

A human increasing the size of their muscles as a result of training

An increase in the number of drug resistant bacteria in a population

Competition for food

Mutation

Variation

The disease affects adult and juvenile rabbits equally.

The disease reduces the ability of the rabbits to reproduce.

Some rabbits are resistant to the disease, and they pass the resistance to their offspring.

No rabbits are resistant to the disease, and all die when the disease strikes them.

A volcano erupts and kills many individuals in a population.

A mutation produces sea stars that are less visible to predators.

An insecticide is sprayed in a community to combat mosquitoes.

Cattle are treated with antibiotics to prevent the spread of infections.