Theory of Evolution

• Charles Darwin, as a result of observations on a round the world expedition, backed by years of experimentation and discussion and linked to developing knowledge of geology and fossils, proposed the theory of evolution by natural selection
• • 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)
• The theory of evolution by natural selection was only gradually accepted because:

  • The theory challenged the idea that God made all the animals and plants that live on Earth
  • There was insufficient evidence at the time the theory was published to convince many scientists
  • The mechanism of inheritance and variation was not known until 50 years after the theory was published.
• Jean-Baptiste Lamarck theories are based mainly on the idea that changes that occur in an organism during its lifetime can be inherited
• Alfred Russel Wallace independently proposed the theory of evolution by natural selection
• Alfred Russel Wallace published joint writings with Darwin in 1858 which prompted Darwin to publish On the Origin of Species (1859) the following year
• Wallace worked worldwide gathering evidence for evolutionary theory
• Wallace is best known for his work on warning colouration in animals and his theory of speciation