Theory of evolutionSpec 4.6.3.1
Charles Darwin proposed the theory of evolution by natural selection as a result of observations on a round the world expedition. His ideas were backed by years of experimentation and discussion, and linked to developing knowledge of geology and fossils.
- Individual organisms within a particular species show a wide range of variation for a characteristic.
- Individuals with characteristics most suited to the environment are more likely to survive to breed successfully.
- The characteristics that have enabled these individuals to survive are then passed on to the next generation.
Darwin published his ideas in On the Origin of Species (1859). There was much controversy about these revolutionary new ideas. The theory developed over time, using information gathered by many scientists.
Why the theory was only gradually accepted
- It challenged the idea that God made all the animals and plants that live on Earth.
- There was insufficient evidence at the time it was published to convince many scientists.
- The mechanism of inheritance and variation was not known until 50 years after the theory was published.
Lamarck
Other theories, including that of Jean-Baptiste Lamarck, are based mainly on the idea that changes that occur in an organism during its lifetime can be inherited. We now know that in the vast majority of cases this type of inheritance cannot occur.