A brief history of life
- Archaea: probably the most ancient form of life, these microbes have evolved to be able to live in some of the most extreme environments on the planet including boiling water and concentrated acid.
- Bacteria: indistinguishable from archaea under the microscope, these bugs have very different biochemical pathways. There are more bacterial cells in and on your body than human ones!
- Single-celled Eukaryotes: these include organisms such as yeast and amoebae. Biochemically these bugs are almost exactly the same as animals, plants and humans, which are all multi-cellular eukaryotes.
- Apart from energy, what other critical requirements are there for life?
- Most metabolic processes are energy generating. What do you think is the most energy-expensive process in a cell?
- Can you identify three niches where you would find anaerobic microbes now?
The Biology of Bugs, Brains, and Beasts

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