Natural Selection + Modern Interpretation

Question 1

what is natural selection?

Answer 1

• The Theory of Natural Selection was put forward in 1859 by Charles Darwin in his book ‘The Origin of Species’
• he had gathered evidence from his observations when working as the ship’s naturalist on the HMS beagle
• much of his important work was done looking at finches on the Galapagos Islands

Question 2

what was Darwin’s theory based on?

Answer 2

• all living things/organisms show variation
• all living things tend to over-reproduce

Question 3

from Darwin’s observations, what were his important deductions?

Answer 3

1. there will be a struggle for existence because organisms over reproduce, and therefore resources will be limited
2. some will be better adapted to their environment than others because they vary
3. those best adapted will survive and reproduce in greater numbers than the less well adapted

Question 4

what has Darwin’s theory taught us about variation?

Answer 4

1. variation occurs due to mutations - these occur randomly and continuously
2. some individuals within a population will have features which make them more able to survive in the environment
3. there individuals with better specialisations are more likely to survive to reproduce
4. they will pass on their advantageous alleles to the next generation
5. therefore the offspring will tend to inherit the advantageous characteristics
6. less favourable alleles tend to become less common in the population
7. this repeats for many generations
8. over time, the specialisations which help organisms to survive will become more common and the characteristics of a species will change