The spontaneous origin of life on Earth Branched Timeline Activity Complete the diagram on the next slide

Spontaneous origin of life Four essential processes; the non-living synthesis of simple organic molecules the assembly of these molecules into polymers the origin of self-replicating molecules that made inheritance possible the packaging of these molecules into membranes with an internal chemistry different from their surroundings.

UV radiation & lightning the Earth”s atmosphere contained ■ nitrogen, water vapour and carbon dioxide; ■ smaller amounts of methane, ammonia, carbon monoxide, sulphur dioxide, hydrogen sulphide and hydrogen cyanide. Describe the evidence from Miller and Urey’s experiments …………………………………………………………………………………………………… Non-living synthesis of organic molecules What recent evidence suggests that Comets brought complex organic Compounds to Earth ? ……………………. …………………… ………………….... complex organic compounds e.g. glucose, ……….…… … ............................................ …………add some of your own ……

Formation of Protobionts Identify what is needed for each of the steps below… The polymers exist in small packages which become different from the surroundings Larger molecules Polymers, big enough to have biological functions Inheritance of the molecules is now possible Organic Molecules If some of the organic molecules function as …………… Causing …………………. If some molecules form primative ………. ……….. That hold the Polymers in one place If a polymer of RNA is surrounded by a ……………… and it replicates and then the membrane ……………………. Into two loops..

Summary – what you have to know Outline the experiments of Miller and Urey into the origin of organic compounds. State that comets may have delivered organic compounds to Earth. Discuss possible locations where conditions would have allowed the synthesis of organic compounds. Outline two properties of RNA that would have allowed it to play a role in the origin of life. Include the self-replicating and catalytic activities of RNA State that living cells may have been preceded by protobionts, with an internal chemical environment different from their surroundings. Examples of Protobionts include coacervates and microspheres. ToK –"falsification of hypothesis" is a problem for many of these theories. Scientists can’t actually travel back in time 4000 million years! The ability to test if the hypothesis is false is an essential ingredient of Science. The idea of Creation – is not Scientific because it can never be tested.