Evidence for Evolution (OCR GCSE Biology A, Combined (Gateway Science Suite)): Revision Notes
📚 Revision Notes
6.3.4 Evidence for Evolution
The theory of evolution by natural selection, first proposed by Charles Darwin, is now widely accepted due to substantial supporting evidence.
Key Evidence for Evolution:
- Fossils:
- Fossils are the preserved remains or traces of organisms that lived millions of years ago, found in layers of rock.
- They provide a historical record of life on Earth, showing how species have gradually changed over time.
- Fossil records demonstrate the existence of species that are now extinct and reveal transitional forms that illustrate the gradual process of evolution.
- Antibiotic Resistance in Bacteria:
- Antibiotic resistance occurs when bacteria evolve in response to the selective pressure exerted by the use of antibiotics.
- Mutations in bacterial DNA can lead to resistance, allowing those bacteria to survive and reproduce in the presence of antibiotics.
- Over time, these resistant strains become more common, providing a real-time example of natural selection and evolutionary change in response to environmental pressures.
