Organisms can adapt to their environment within one generation

Organisms can adapt to their environment within one generation if they are selected naturally by the nature.

Explanation:

Organisms can survived which can withstand or tolerate the harsh climate of the environment while some organisms removed from that environment due to low survival ability in that harsh climate. This selection is done by nature in which well suited animals and plants can survive in that environment due to certain adaptations. Those organisms can adapt to their environment within one generation due to survival ability and high fitness.

For example, in deserts, bears did not survive because it requires cold climate so only reptiles such as snakes and lizards can survive in this environment.