Natural Selection
Biology: AQA GCSE Higher, topic 6.2.3
Natural Selection
Natural selection was proposed by Charles Darwin in 1859. He theorised that all species evolved from simple life forms that first appeared on Earth more than three billion years ago. Natural selection happens like this:
Genetic variation
- Within a biological population, different individuals have genetic variation (differences in characteristics).
Survival of the fittest
- Individuals possessing genes that make them better adapted to the environment will have a greater chance of survival.
Breeding
- Individuals with the best chances of survival are the most likely to breed successfully (because they survive).
Best characteristics survive
- The characteristics responsible for the increase in the likelihood of survival are more likely to be passed on to the next generation.
Test yourself on Natural Selection
Which of these conditions or outcomes is NOT connected to the process of natural selection?
Natural Selection
Why must an individual survive before it can pass on genes that improve survival chances?
Why does genetic variation within a population affect individuals' chances of survival?
Why are individuals that are better adapted to their environment more likely to breed successfully than others?