Darwins concept He was born February 12th 1809 Darwin developed the biological theory of evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors. In 1831, he began a 5 year voyage on the HMS Beagle that would change his life. Darwin thought about the patterns he’d seen on his voyage He realized that there were many similarities between the animals he’d seen There was evidence that suggested that species were not fixed and that they could change by some natural process Proposed that the use or disuse of organs caused organisms to gain or lose traits over time. These new characteristics could be passed on to the next generation. Lamarck’s hypotheses were incorrect in many ways However, Lamarck was one of the first to: Suggest that species are not fixed Explain that evolution uses natural processes Recognize that there is a link between an organism’s environment and its body structures Lamarck’s work paved the way for later biologists, including Darwin In 1798, Thomas Malthus noticed that people were being born faster than people were dying. How this helped Darwin He reasoned that what Malthus proposed for human populations also applied to all living things. Struggle for Existence From Malthus’ theory of supply and demand, Darwin reasoned that if more individuals are produced than can survive, they will have to compete for food, living space and other necessities of life Darwin described this as the struggle for existence Individuals have natural variations among their inheritable traits Fast predators capture prey more efficiently Prey that are faster, better camouflaged or better protected avoid being caught. Any heritable characteristic that increases an organisms ability to survive and reproduce in its environment is called an adaptation’’ Ability to survive and reproduce in a specific environment is called FITNESS Fitness is a result of adaptation Good adaptations allow organisms to survive and are passed on to their offspring. Good fitness: reproduce Low fitness: few offspring/extinction