Exercises: The origin of life

Describe what early Earth was like at the time life emerged: its atmosphere, its oceans and its geological activity.

Look at the diagram of the apparatus with which Miller and Urey carried out their famous experiment in 1953. Identify what the parts labeled ?1 to ?4 represent (the gas mixture, electrical discharges, boiling water and the collection trap), explain what conditions of early Earth they simulated in the laboratory and what type of molecules they obtained.

What is astrobiology? Explain what it studies and why searching for life outside Earth helps us understand the origin of life on our planet.

For centuries, it was believed that living organisms could arise from non-living matter: worms from decaying meat or mice from dirty clothes. Describe what the hypothesis of spontaneous generation consisted of, and explain how it was experimentally disproved by Redi with his jars of meat, Spallanzani with boiled broths and, above all, Pasteur with his swan-neck flasks.

Current hypotheses on the origin of life include chemical synthesis in the "primordial soup", panspermia and hydrothermal vents on the ocean floor. Summarize them briefly and then order and explain the steps necessary to go from individual molecules to the first cell: appearance of hereditary material capable of copying itself, formation of complex organic molecules, appearance of metabolism and formation of membranes.

Why is the search for life on other worlds so focused on finding liquid water? Explain which properties of water make it so important for living things.