Biology 1201A Chapter Notes - Chapter 3: Reducing Atmosphere, Termite, Homeostasis
15 Jul 2015
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Seven characteristics shared by all life-forms: order, harnesses, utilizes energy, reproduces, responds to stimuli, exhibits homeostasis, grows, develops & evolves, viruses: lack cellular machinery to synthesize own proteins; why they infect living cells. Characteristics of life are emergent: emerge from many simpler interactions, that in themselves, do not have properties found at higher levels, ex. termite cathedral, earth is 4. 6 billion years old, homo-sapiens: 150,000 years old, pg. Biologically important molecules can be synthesized outside of living cells: 1. > primordial- water vapor, hydrogen, carbon dioxide, ammonia, methane; almost complete absence of oxygen. > today: oxidizing atmosphere- presence of high levels of oxygen prevents complex, electron- rich molecules from being formed. > ozone layer (03): developed after oxygen levels increased in atmosphere. > miller grey experiment: placed components of reducing atmosphere (h2, ch4, nh4, water vapor) into closed apparatus, exposed gases to energy source (sparking electrodes: 2. > near sites of volcanic or tectonic activity.
