7.1 Theories of Evolution

Life has been estimated to have begun on Earth 3 billion years ago. Before the 18^th century there were few scientific idea in how evolution works.

Jean-Baptiste Lamarck suggested a theory call ‘the inheritance of acquired characteristics’. His theory stated that the characteristics which develop during an organism’s lifetime can be passed on to the next generation. People found this difficult to believe. For example, if two parents were to build up their muscles in a gym, Lamarck’s theory would predict that this characteristic would be passed on to their offspring.

Charles Darwin suggested the theory of ‘natural selection’ after he had made a journey to the Galapagos Islands. He recorded many observations about life on the islands. His theory stated that small changes in organisms took place over a long time. All organisms in a species vary and therefore some are more likely to survive (natural selection). Those that are the best adapted breed and pass on their characteristics/genes.