BIOL 1201 Chapter : Biology 1201
Document Summary
4. 2-4. 7 billion years ago life began we have explanations/ hypothenises to explain life. not a theory: ockham"s razor: simplest explantation is the most likely/ most probable keep it simple. observations= explanations. Over time, leads to a theory. scientific method: several observations lead to a theory: no evidence to suggest life started somewhere else besides earth, charles darwin did not discuss how life began, he talked about how life changed. How did life begin? a few centuries ago: people thought that new living things appeared all the time. Spontaneous generation refuted: (proven wrong: mid-1800s louis pasteur (pasteurized milk) boiled to kill microorganisms. Earth before life arose: earth is about 4. 6 billion years old look at the moon by looking at certain elements and their breakdowns. half lives. radioactive dating of meteorites and moon rocks. Life arose about 3. 8 billion years ago. arose as soon as we had liquid water.
