Summary Easy to Follow GCSE Notes on Evolution and Natural Selection

Evolution and Natural Selection


Charles Darwin, formulated the idea of natural selection and created the
term, ‘Survival Of the Fittest’


Darwin’s Theory of evolution states:
- Individuals in a species show a range of variation caused by differences
in genes
- Individuals with characteristics most suited to the environment have a
higher chance of survival and more chances to reproduce
- Therefore, these characteristics are passed to their offspring at a
higher rate from those with characteristics less suited to survive
- This idea of natural selection became known as ‘Survival of the fittest’


Antibiotic Resistance in Bacteria:
- An example of natural selection is the rise of antibiotic resistance in
bacteria
- Antibiotics are chemicals that kill bacteria
 They often do this by punching holes into the bacterial cell wall
- A mutation might produce a new allele that is resistant to a particular
antibiotic
 This allele will give the bacteria increased survivability
- Due to natural selection, this allele will spread through the population,
leading to infections being difficult to control