Evolution and extinction Flashcards
What is evolution?
Evolution is the gradual change of inherited characteristics of biological populations over time.
When does speciation happen?
When two animal populations diverge (separate or split) a lot.
What are the two main sources of evidence of evolution?
- Antibiotic resistant bacteria
- Fossils
What are the causes of fossilisation?
- Hardening soft materials
- Mineral replacement
- Where decay isn’t possible –> peat bags and glaciers
What does Charles Darwin’s theory of natural selection propose?
All species have evolved from simple life forms that first appeared on Earth more than three billion years ago.
What are the steps for natural selection?
- Genetic variation
- Survival of the fittest
- Successful breeding
- Best characteristics survive
What opposing points did Darwin face?
- Religion
- Inconclusive evidence
- Genes were yet to be discovered
When does extinction happen?
When there are no individuals of a species left in the world.
What factors can cause extinction?
A change in abiotic (physical) or biotic (relating to organisms) factors can cause extinction if a species cannot adapt or move to another environment.
Geological and atmospheric changes happening over a ____ time scale can cause ____ extinctions.
long, slow
