Microscopic life
Microscopic organisms were first observed about 300 years ago.
They are known as micro-organisms or microbes and a microscope is needed to
see them.
Microbes belong in the Protist or Monera kingdoms. Microscopic fungi such as
yeasts and moulds can also be classified as microbes.
Protists
Protists live in oceans, rivers, lakes, ponds or in moist soil.
There are two main types
Algae
These are plant-like and contain chlorophyll. They make their own food by
photosynthesis.
Protozoans
These are animal-like as they don’t contain chlorophyll and they move around to
catch and eat food.
There are structures on many protists to help them move through water.
They have cilia on the outside of their bodies or flagella that look like long whiplike tails.
Some protests are large. (Seaweed) These are multicellular protists.
(Diagrams of protists)
Bacteria
Most monerans are unicellular and include bacteria and blue-green algae.
They are very simple and contain no distinct nucleus.
They are too small to be seen even with a normal light microscope. A scanning
electron microscope is needed.
Bacteria can be classified according to their shape.
Rod shaped, Spherical and spiral shaped.
Sometimes rod and spiral shaped bacteria have flagella to help them move.
Sometimes they form chains and sometimes they group together. They have an
outside coating to allow them to stick together and also to stick to other objects.
Bacteria prefer warm wet places to live. They get oxygen from water.
Bacteria die if they dry out.
In swampy areas they feed on decaying vegetation and produce methane gas as a
result.
Bacteria and fungi are known as decomposers as they live on dead organisms.
Some bacteria live inside living organisms and cause disease, (tetanus and food
poisoning)
There are many more bacteria in humans than other cells. (A factor of 100)
Most bacteria is beneficial in humans.