1. There are numerous theories as to how life began. Some of the most popular ones include: DIVINE ORIGINS The BIG BANG THEORY METEORITE PRIMORDIAL SOUP BUBBLE THEORY

2. BIG BANG Universe was created by a giant explosion All matter moved out and away from central condensed ball of matter Stars and planets were created Universe is still expanding Relates to meteor theory

3. PRIMORDIAL SOUP Most widely held theory Earth’s oceans were a primordial soup full of organic matter Energy from the sun, volcanoes, and lightning fueled chemical reactions the combined the molecules into amino acids, lipids, and other complex organic molecules

4. PRIMORDIAL SOUP Several billion years ago Earth’s atmosphere had no free oxygen. Elements/chemicals were only in the atmosphere When the earth cooled elements entered the oceans Primitive oceans filled with organic chemicals were called the primordial soup Since the 1950’s scientists have shown that amino acids will link together to form proteins when heated to form parts of a cell Protocell=a primitive cell-like ordered structure that carried out growth, cell division, or metabolism

5. Biogenesis= beginning of life: protocells were formed from inorganic chemicals  precursors to prokaryote cells

6. Endo= inside or within Symbiotic= relationship between living organisms Eukaryotic protocells engulfed prokaryotic bacterial cells which could carry out photosynthesis and cellular respiration The eukaryotic cells then contained pre-chloroplasts and pre-mitochondria which evolved into plant-like protists (ancestors of eukaryotes on earth today)

7. Endosymbiotic diagram