Y4 Unit 3: Natural and artificial selection

what is natural selection

organisms with desirable characteristics are selected or favoured to survive and pass on their traits/characteristics to their offspring

What is evolution

gradual change in the inheritable characteristics of a population over time (several generations)

4 steps to describe process of natural selection

1. Pre existing variation (what is currently present)

2. Selection pressure/force (how is variation selected that fits environment)

3. Differential survival and reproduction (with variation → survive + reproduce to pass favourable trait to next generation)

4. Evolutionary change (over generations, variation will be passed on)

How does evolution via natural selection work

1. Variation + competition for survival

   1. Organisms die due to competition and predatory behaviour

   2. Variation and competition → deferential survival and reproduction by organisms best fitted to environment

2. Survival of the fitter

   1. Favourable characteristics = better adapted = likely to survive

3. Reproduction, pass on favourable traits (that are heritable)

Factors driving natural selection

1. Competition for resources

2. Predation

3. Destruction by humans

4. Environmental factors

5. Habitat loss

What is artificial selection

Specifically chosen parents with certain traits, offspring with desired trait kept, offspring without desired trait directly killed or removed