Theories of Evolution • Lamarck believed in acquired characteristics. • The characteristics that help that organism to survive are passed to their offspring. • So if your parents are body builders then you are born that way.
Theories of Evolution • Darwin set out in 1831 on a voyage. • The galapagos islands he saw different features on a variety of finches
Survival of the fittest • Only offspring with the genes that best suit their habitat will stay alive and breed. • This is natural selection.
A fast runner on hard ground • It has one toe forming a hoof • Looks more like the modern horse with one hoof • Slightly bigger • Walks mainly on one toe • Has 3 toes on the ground • To run faster on drier ground • Small • Lives on swampy land • Toes are well spread
Predators • The dodo was a flightless bird. • New predators arrived on shore and they could not escape.
Environmental changes • Scientists believe a big climate change caused dinosaurs to become extinct due to a meteorite crashing into the earth.
Competition • A mutation can give one animal an advantage over another. • Or sometimes one species can not compete with another as they are better adapted to their environment, causing extinction.
Diseases • Diseases can wipe out a whole species quickly when the population live close together.
Predators Competition Environmental changes Diseases Extinction
What are the two different theories proposed by Lamarck and Darwin, describe them. • What is the theory of evolution? • Describe how finches helped Darwin to develop his theory. • What evidence do we have to prove evolution has taken place? • Explain why Darwin’s theory was only accepted gradually (give two reasons). • Describe how natural selection works. Give an example of natural selection. • What is a mutation? And how can this be advantageous for an organisms?