Facts At Your Fingertips: The living world – Evolution
Over millions of years, living things change in response to differences in their environment. This is called evolution and it happens through a process called natural selection.
Changes that are more likely to help a plant or animal survive are passed to future generations, but living things with changes that are not suited to survival die out.
Adaptation
Natural selection has produced living things that are superbly adapted to life in the places where they live.
Species that have adaptations better suited to an environment are more likely to survive than those that do not. Plants in deserts need to be able to save water, while animals in the Arctic need to survive the cold.
Human evolution
Humans evolved from apelike ancestors over millions of years.
In that time, different species evolved and were replaced until modern humans first appeared about 200,000 years ago.
Ardipithecus ramidus (4.5 million years ago)
Australopithecus afarensis (3 million years ago)
Homo habilis (2 million years ago)
Homo erectus (1.5 million years ago)
Homo heidelbergensis (500,000 years ago)
Homo sapiens (200,000 years ago)
Extinction
Changes to the environment, such as climate change, can lead to the disappearance of a whole species in a process called extinction.
Extinction is an important part of the evolution process because it gives other species the chance to replace extinct ones.
The dinosaur Corythosaurus became extinct about 75 million years ago