I will give a micropalaeontology lecture tomorrow to the first year geology students.
I was asked to give this lecture because I did my PhD on the pattern of microfossil extinction in the Silurian.
Microfossils are a little known group, usually only a few thousandths of a millimetre across, that are very important in climate change and global ecosystems. Amazingly, up to 1/3 of all photosynthesis takes place in microscopic algae in the sea. Microfossils are also incredibly important in the carbon cycle. When they make their shells, they take carbon dioxide out of the atmosphere. This effectively acts as a thermostat by stopping the planet from getting too hot through the greenhouse effect.
It is incredible to think that the White Cliffs of Dover and Flamborough Head are both made out of millions and millions of microscopic fossils.