Evolution Biology

Evolution is change over time THEORY: best explanation science has to offer about where different organisms came from This theory changes as new scientific information becomes available

Scientists of Note – John Lamarck Early theory that acquired traits (like “big muscles”) could be passed on from parents to offspring Disproven

Charles Darwin Father of modern evolution theory Formed his theory after traveling around the world on the Beagle Important stop: Galapagos Islands

Darwin’s observations: Variation: differences between members of the same species Variation is important to survival! Why?

What causes variation? Mutations *organisms do not mutate because it will benefit them.

Darwin’s observations: Finches (type of bird) 13 species of finches Found on different islands Beak size and shape varied Ate different food

The bird’s with the best beaks were able to survive!

Darwin called these mutations or changes ADAPTATIONS Variety in a species that make it easier to survive

Natural Selection Organisms with traits well suited to the environment survive and reproduce at a greater rate You have the genes to be successful in your environment or you don’t Variety already exists, some varieties better fit to environment than others

“Survival of the fittest” If you are better fit for your environment, you will survive You will reproduce Over time, population will be more like those that reproduce