The environment needs to change for natural selection to occur. Populations have some genetic variation. Nature selects organisms with specific traits to survive and reproduce.
Natural selection is an evolutionary process that occurs as a result of environmental changesOrganisms adapt to their environment as it changes and the traits are then passed to their offspring for survival while those who aren't able to adapt die.
Natural selection occurs chooses traits which have an advantage and the organisms having different traits is what is referred to as genetic variation.
