Evolution of life on Earth Flashcards
When did life on Earth begin? What kind of life was it?
3500 million years ago, very primitive and simple bacteria and organisms
How have we evolved from being these simple life forms.
Mutations change the genetic information in a cell and affect an organisms characteristics. If a mutation occurs as sex cells are produced, the mutation is inherited by the offspring. Most are harmful but sometimes new mutations are useful and will be passed on throughout the population
What is the current theory for how we are what we are today?
Darwin’s theory of evolution, it provides the best explanation for the enormous number and variety of organisms.
In which ways can useful characteristics be passed on?
Natural selection, where randomly a new mutation occurs and spreads as the organisms displaying this are best suited to surviving (survival of the fittest.
Selective breeding is an artificial process in which specific organisms will be bred to produce offspring with the specific require traits.
How are new species created?
If a species of organism become separated and live isolated in different environments, natural selection will act on each group differently and over time they will become distinct and unable to reproduce. A new species
What was the previous theory for evolution and why was it discredited?
Previously people believed in Lamarck’s theory, however with understanding of genetics and the evidence for inheritance Darwin could prove his theory he developed on the Galapagos island.
When and where did Darwin propose his theory?
He proposed the theory with Alfred Russel Wallace in 1859. He had thought of it after studying mockingbirds on the Galapagos island. He knew they must have come from the mainland, but from island to island they were different
