Natural selection~

• The two scientists that proposed theories about evolution were Charles Darwin and Alfred Wallace.
• The idea behind the theory of evolution by natural selection is that all species of living things have evolved from simple forms over a period of time.
• Planet earth is supposedly around 4.5 billion years old.
• Scientists believe that life began around 3 billion years ago.
• How a species evolves due to natural selection


  1. Individuals in a species show a wide range of variation because of differences in their genes caused by random mutations

  2. Individuals with characteristics most suited to their environment are more likely to survive and reproduce (survival of the fittest)

  3. The advantageous genes are then passed down to their offspring

  4. The population of these individuals will increase

  5. Individuals that are poorly adapted to their environment are less likely to survive and reproduce. Their numbers will then decrease

  6. Over a period of time, a species will gradually evolve
• Two populations of the same species become increasingly different in phenotype


  They can no longer interbreed to form fertile offspring, this can result in the formation of two species
• The name for the organisms that have an advantageous gene and are more likely to survive and reproduce are called the survival of the fittest.
• Camouflage as an adaptation is an advantage to prey organisms as they can hide from predators.
• Before the industrial revolution the type of moth that predominated were the light moth.
• The reason for this is because they were adapted to their environment (they could camouflage into the trees away from predators.)
• After the industrial revolution, the moth that predominated was the dark moth as the air pollution was quite high and the trees became dark so that they could camouflage into them.They became more adapted to the environment and they increased in number.
• After the industrial revolution, the light coloured moths started to decrease as they weren't able to camouflage into the trees and they got eaten by predators.
• When Charles Darwin was in the galapagos islands he studied finches.
• Darwin noticed that on the different islands the finches beaks' showed variation.
• The finches beaks were different depending on their local food source.
• He concluded that because the islands are so distant from the mainland, the finches that had arrived had evolved over time.