Thursday, April 21, 2011

The Five Kingdom of Life and The Characteristics Of Living Things

Until fair recently, all living things were classified as either plants or animals this simple division is perfectly adequate for non scientific purposes, but most biologists now recognize five separate kingdoms of life, based largely on microscopic structure and bio chemical activity, these are the bacterial kingdom, or Prokaryote; the Protoctista; the Fungal kingdom; the Plant kingdom and the Animal kingdom.
Although we cannot give a simple definition of life, there are seven distinctive features that are shared by all living things and distinguish them from inanimate objects.

These characteristics are:
Movement
Excretion
Respiration
Reproduction
Irritability
Nutrition
Growth
The initial letters of these features form the word MERRING, a convenient mnemonic for keeping them in mind.
The Kingdom of Prokaryote:
This kingdom contains the bacteria. These are all microscopic, single celled organisms, but their structure is very different from that of other single celled organisms, with no obvious nuclei or other well defined structures – organelles- within the cell division, sometimes as often as once every 15 minutes. Some bacteria can carry out photosynthesis, using the energy of sunlight just as plants do, but most of them rely on other chemical reactions to provide their energy. Bacteria play a major role in the natural world, where they are heavily involved in the breakdown of dead plants and animals and return back to the soil.