Lamark’s theory of evolution

• In the 19th century, scientists were developing theories of evolution
• Lamarck's theory of evolution

  Jean-Baptiste Lamarck was a French biologist who thought that all organisms were linked by what he called a fountain of life, and that organisms evolved to suit their environment. His idea was that every type of animal evolved from primitive worms, and the change from worms to other organisms was caused by the inheritance of acquired characteristics.
• Lamarck's theory


  1. Organisms' behaviour affects the features of their body - a case of use it or lose it

  2. If animals used something a lot over a lifetime, Lamarck thought this feature would grow and develop

  3. Any useful changes that took place in an organism during its lifetime would be passed from a parent to its offspring

  4. If a feature wasn't used, Lamarck thought it would shrink and be lost
• Lamarck's theory


  • The neck of the giraffe is a good example
• Lamarck's theory influenced the way Charles Darwin thought
• There were several problems with Lamarck's ideas, including no evidence for his 'fountain of life' and people didn't like the idea of being descended from worms
• People could also see quite clearly that changes in their bodies, such as big muscles, for example, were not passed on to their children
• We now know that in the great majority of cases, Lamarck's idea of inheritance cannot happen
• However, Lamarck's ideas paved the way for the scientists such as Darwin who followed him