Bacteria (singular bacterium) are single-cell tiny living organisms (microorganisms) – they are neither plants nor animals – they belong to a group all by themselves. Bacterial cells are so tiny that a gram of soil is estimated to contain about 40 million bacterial cells. A milliliter of fresh water may contain up to one million bacterial cells.
Bacteria come in three main shapes:
- Spherical (like a ball). These are usually the simplest ones. Bacteria shaped like this are called cocci (singular coccus).
- Rod shaped. These are known as bacilli (singular bacillus). Some of the rod-shaped bacteria are curved; these are known as vibrio.
- Spiral. These are known as spirilla (singular spirillus). If their coil is very tight they are known as spirochetes.
Where Are Bacteria are found?
They are found almost everywhere even the most unlikely places where temperatures may be extreme, or where there may be a high concentration of toxic chemicals. Those found in extreme environments are known as extremophiles (an extremophile is any organism adapted to living in conditions of extreme temperature, pressure, or/and chemical concentrations) – these bacteria can survive where no other organism can.
Some of the places where bacteria have been found include:
- Radioactive waste
- Deep in the earth’s crust
- Organic material
- Arctic ice
- Hot springs
- The stratosphere (between 6 to 30 miles up in the atmosphere)
- Ocean depths – they have been found deep in ocean canyons and trenches over 32,800 feet (10,000 meters) deep. They live in total darkness by thermal vents at incredible pressure. They make their own food by oxidizing sulfur that oozes from deep inside the earth.