Charles Darwin and Natural Selection

Darwin’s Ideas Influenced by: Voyage on the Beagle (1831-1836) Lamarck’s Theory of Evolution Also influenced by…

Geologists James Hutton and Charles Lyell Processes that form rock, mountains, and valleys are very slow Earth is much more than a few thousand years old Lyell Geological processes we observe now have occurred for millions of years Explains why marine fossils are at tops of mountains

Thomas Malthus, Economist Babies born faster than people dying If population growth continued, people would run out of food, water and space War, famine and disease prevents this

Fossils

Artificial Selection Breeders select best traits to produce next generation

Darwin’s Theory of Evolution by Natural Selection Living things overproduce

Darwin’s Theory of Evolution by Natural Selection There is variation among offspring

Darwin’s Theory of Evolution by Natural Selection There is a struggle to survive

Darwin’s Theory of Evolution by Natural Selection Those that survive are most fit

Natural Selection: “Survival of the Fittest” Fitness = ability to survive and reproduce Fitness is the result of adaptations – inherited characteristics that increase an organism’s chance of survival

Descent with Modification Over time, natural selection produces organisms with different structures Today’s species look different from their ancestors Each species descended with changes over time

Descent with Modification Implies that all living things are related to one another COMMON ANCESTOR