The six kingdoms of life :

 1 ARCHAEA :

     The first life forms to evolve on earth were the microscopic organisms called archaea. They have a very small structure just a single cell enclosing a tiny drop of watery fluid containing the molecules vital to life. Some archaea live in hostile places such as hot, acidic springs. Archaeans include inhabitants of some of the most extreme environments on the planet. Some live near rift vents in the deep sea at temperatures well over 100 degrees Centigrade. Others live in hot springs (such as the ones pictured above), or in extremely alkaline or acid waters. They have been found thriving inside the digestive tracts of cows, termites, and marine life where they produce methane. They live in the anoxic muds of marshes and at the bottom of the ocean, and even thrive in petroleum deposits deep underground.

Some archaeans can survive the desiccating effects of extremely saline waters. One salt-loving group of archaea includes Halobacterium, a well-studied archaean. The light-sensitive pigment bacteriorhodopsin gives Halobacterium its color and provides it with chemical energy. Bacteriorhodopsin has a lovely purple color and it pumps protons to the outside of the membrane. When these protons flow back, they are used in the synthesis of ATP, which is the energy source of the cell. This protein is chemically very similar to the light-detecting pigment rhodopsin, found in the vertebrate retina.

2 BACTERIA :

 Some bacteria are harmful but must serve a useful purpose. They support many forms of life, both plant and animal, and they are used in industrial and medicinal processes. Bacteria are thought to have been the first organisms to appear on earth, about 4 billion years ago. The oldest known fossils are bacteria-like organisms. Bacteria can use most organic and some inorganic compounds as food and some can survive extreme conditions. A growing interest in the function of the gut microbiome is shedding new light on the roles bacteria play in human health. These are very like archaea, with the same structure. But their chemistry is different showing that they evolved separately. Some bacteria cause diseases while others are essential to our survival. One type, cyanobacteria, produced nearly all the oxygen in the atmosphere.

3 PROTISTS :

 Protists are a diverse collection of organisms. While exceptions exist, they are primarily microscopic and unicellular or made up of a single cell. The cells of protists are highly organized with a nucleus and specialized cellular machinery called organelles. At one time, simple organisms such as amoebas and single-celled algae were classified together in a single taxonomic category: the kingdom Protista. However, the emergence of better genetic information has since led to a clearer understanding of evolutionary relationships among different groups of protists, and this classification system was rendered defunct. Understanding protists and their evolutionary history continue to be a matter of scientific discovery and discussion. Also known as algae and protozoans., these are mainly microscopic single-celled organisms. Unlike bacteria or archaea, each cell has a nucleus that contains the main life-giving molecules. There is also another structure within the cell that makes food or turns it into energy.

4 FUNGI :

    The Kingdom Fungi includes some of the most important organisms, both in terms of their ecological and economic roles. By breaking down dead organic material, they continue the cycle of nutrients through ecosystems. In addition, most vascular plants could not grow without the symbiotic fungi, or mycorrhizae, that inhabit their roots and supply essential nutrients. Other fungi provide numerous drugs (such as penicillin and other antibiotics), foods like mushrooms, truffles and morels, and the bubbles in bread, champagne, and beer. Although they seem to grow like plants fungi feed on other living or dead organisms. Some fungi are single-celled microbes but most fungi from spreading multi-celled root networks. These produce mushrooms and moulds like those that grow on decaying fruit.

5 PLANTS :

 These living organisms are made of eukaryotic cells and are multicellular. The cells have a cell wall that is made of cellulose. These are autotrophic and synthesize food by photosynthesis due to the presence of chloroplasts. Green plants are multi-celled living things that use the energy of sunlight to nake food. In the process, they release oxygen into the air which is vital to animal life. They mostly live on land or in fresh water and range from low growing mosses to magnificent trees.

6 ANIMALS :

   The classification helps in easy identification and also in assigning a systematic position to newly described species. In spite of differences in structure and form of different animals, there are fundamental features common to various individuals in relation to the arrangement of cells, body symmetry, nature of coelom, patterns of digestive, circulatory or reproductive systems. These features are used as the basis of animal classification  Like plants, all animals are multi-celled organisms. But unlike them, they can not make their own food and must eat other organisms instead. Most do so by moving around using their senses to find the food they need and this has led to the evolution of intelligence.