The Kingdoms of Organisms - Essay Example

Kingdoms of Living Organisms" (http winnivangessel.home.insightbb.com/MMSK/5_kingdoms.htm) Introduction Life started off on the planet with simplest form and gradually with evolution and passage of time new species derived from these simple forms, creating more than 1.8 million species of various kinds. Based on resemblances or variations of characteristics, species are classified into various categories by numerous scientists. The widely accepted one is The Five Kingdom Classification given by Carl Linnaeus.

This classification categorize living beings on the basis of approach for nutrition and their cellular association. This classification is in contrast to the previous classification encompassing two categories, plants and animals. In this classification viruses, the connecting link between the living and the non-living world are not included. The Linnaean system includes-I. Kingdom Monera- This kingdom includes prokaryotes, organisms with primitive form of nucleus as the nucleus does not possess any defined nuclear membrane.

The organisms are single-celled and absorb nutrition through their cell wall.E.g. Bacteria, Cyanobacteria or blue-green algae (popularly called as BGA, are prokaryotes and are connecting link between chlorophyll containing algae and bacteria) and spirochetes, the spiral single cellular organisms. Lately, the kingdom is further divided into two categories, Eubacteria or true bacteria and Archebacteria or bacteria like organisms capable of surviving in extreme environmental conditions like hot springs and volcanic expels. II. Kingdom Protista- This kingdom includes eukaryotes (Organisms with well defined nucleus, nuclear membrane and membrane bound cellular organelles are present).

The organisms belonging to this category are single celled and are neither plants nor animals as they are diverse forms and need a separate group in the classification. Some of the organisms belonging to this category possess chlorophyll and therefore like plants, they can produce their own nutrition, while others procure nutrition by means of absorption and ingestion processes.E.g. Amoeba, Algae, sea kelp. Euglena, Chlamydomonas etc. III. Kingdom Fungi- This group includes organisms that possess many cells and are called multicellular organisms.

They are non-motile and their structure encompass hyphae and mycelium. These organisms do not possess chlorophyll and are dissimilar to plants. This group includes organisms of diverse size from microscopic yeast cells to large mushrooms. Fungi derive their nutrition by means of absorption. They proliferate on the dead as well as decaying organic matter and procure nutrition.E.g. molds, yeasts, mildew, smuts and mushrooms.IV. Kingdom Plantae- This kingdom includes multicellular organisms, with well defined nucleus, enclosed by nuclear membrane and cellular organelles.

They possess chlorophyll, the photosynthetic pigment responsible to perform photosynthesis and fix carbon-di-oxide in the presence of water and sunlight, produce sugar, convert sugar into starch and store it for the consumption of herbivores and omnivores. During the process, oxygen is released which is the vital gas for the survival of living beings on the planet. E.g. Algae, mosses, ferns, flowering and non-flowering plants. V. Kingdom Animalia- They are multicellular, eukaryotic and motile organisms.

They do not possess chlorophyll and are solely dependent on plants, either directly or indirectly for their food. They therefore possess ingestion as the mode of nutrition.E.g. insects, worms, fish, reptiles, amphibians, birds and mammals. Conclusion All these kingdoms are correlated on the cellular basis. The genetic composition of all living organisms is the same as the DNA, RNA and proteins are conserved across the kingdoms and throughout the evolution.References"5kingdoms of Living Things".

22nd November 2011. .