Bacterial cells are about 10 times as many as human cells in the human body. And there are so many bacteria that we can ever imagine. Actually, our body is packed with different kinds of bacteria. These bacteria are found mainly all over our skin and in our digestive tract. Even though they are tarnished for their part in causing human diseases not all of them are damaging to our body as we have thought. There are good species that are necessary to a healthy body. Bacteria that live in our intestine are in reality helpful. They make necessary vitamins and have the defensive effects that aid our immune system fight against sure diseases.

On the Other hand there is as well what we called bad bacteria. These bad bacteria are accountable for causing infectious diseases for example strep throat, tuberculosis, syphilis, whooping cough, pneumonia, leprosy and many more. Bacteria or bacterium are very small unicellular microorganisms although be able to just be seen by the use of a powerful microscope.

Yet, there are discoveries of a kind of bacteria that can be seen straight by our bare eyes. They are million times bigger than a usual bacterium, and they can be found inside a tropical fish. The scientists believed that bacteria have existed long ago on earth for about three and a half million years by now. They are everywhere in every habitat on earth as well as adapted to all kinds of environment. Bacteria are broadly distributed. These bacteria can survive in either extreme cold like in arctic snow or even in boiling hot springs. These bacteria can also grow in soils, radioactive waste and down on the ocean floor.

NASA Team even found bacteria 19 miles or 30 kilometers out in space. Bacteria are spread all over the world and have been estimated to make up to 5 up to 25 times the total mass of all other animal life combined. The word bacteria were usually practical to all microscopic, single celled prokaryotes. Not like animals as well as other eukaryotes, bacterial cells do not have nucleus or other membrane bound organelles.

Yet, two divided evolutionary domains called Bacteria along with Archae where known to have consist the prokaryotic life. Bacteria and Archae are at first called Eubacteria and Archaebacteria. Yet, introduction to molecular systematic as well as their analysis of genome sequences, bacterial classification remains a changing as well as expanding field.