Origin of Life
Planet Earth formed 4.6 billion years ago
The early atmosphere contained H2, H2O, CO, CO2, N2, NH3, CH4
No oxygen
Lightning, volcanic activity and UV radiation were intense - no Ozone layer
How did life originate on early Earth
Miller Urey Experiment - simulate early Earth
Boiling Chamber - oceans
Spark Chamber - atmosphere
Electrodes - lightning
Results: monomers
Amino acids
Monosaccharides
Nucleotides
Nucleotides
Components to make lipids
Creation of first real cells
Certain molecules, such as polypeptides can self-assemble into fluid-filled spheres
Prokaryotes
oldest life forms
when first organisms rose, there was little or no oxygen in existence. thus the first cells were anaerobic
these cells were all prokaryotes
archaebacteria
live in extremely harsh conditions
Cyanobacteria
ancient photosynthetic prokaryotes are the oldest known fossils
primary producer of O2 as early as 3.5 bya
Change in Atmosphere
with more photosynthetic prokaryotes, the atmosphere became more aerobic
oxygen catastrophe
mass extinction
new niches available
oxygen eventually became plentiful and completely changed the organisms found on Earth
Anaerobic to aerobic
click to edit