Energy is an essential requirement for all living things (organisms). Organisms need energy for things like growth, movement, reproduction and repair/maintenance. If we look closer, we find that the cells that make up these organisms require energy for the same reasons. Organisms obtain energy in physical or chemical form from their environment and transformations occur within the cells. Find out more about these transformations in the videos - 'Food Chains - Autotrophs and Heterotrophs', 'What is Photosynthesis?', 'What is Aerobic Respiration?' and 'What is Fermentation (Anaerobic Respiration)?'. For more Biology video lessons check out www.anytimeeducation.com