Diversity In Living Organism

Diversity In Living Organisms

Different Forms In Which Life Occurs Microscopic Bacteria - Few Micrometres Blue Whale - 30 Metres Red Wood Trees Of California - 100 Metres Some Pine Trees - Lives For 100 Of Years Insects Like Mosquitoes - Live For Only A Few Days A characteristic is a particular form of a particular function.All living things are identified and categorised on the basis of their body design in form and functionBasic characteristics used for a hierarchical classification. Whether the organism is unicellular or multicellular forms one of the most important basic characteristics of classification. Whether the organism is eukaryotic or prokaryotic. Another characteristic is understanding whether the cells occur singly or in groups. If the cells occur in groups, does it have division of labour or not. Whether the organisms are autotrophic or heterotrophic. What is the level of organisation of the organisms performing photosynthesis (plants). Of the animals, how does the individual's body develop and organise its different parts and what are the specialised organs found for different functions ? CLASSIFICATION AND EVOLUTIONMost life forms that we see today have arisen by an accumulation of changes in body design that allow the organism possessing them to survive better. Charles Darwin first described this idea of evolution in 1859 in his book, The Origin Of Species.The groups of organisms which have ancient body designs that have not changed very much are referred to as primitive or lower organisms.The groups of organisms that acquired their particular body designs relatively recently are referred to as advanced or higher organisms.Biodiversity Biodiversity means the diversity of life forms. It is the variety of life forms found in a particular region Land, water, climate etc. are the factors that affect the diversity of stable communities of different species. Diverse lifeforms share the environment, and are affected by each other too. The warm and humid regions of the earth having tropical climate, between the tropic of Cancer and tropic of Capricorn, are rich in plant and animal life. This is called the region of megadiversity. More than half of the diversity of the planet Earth is concentrated in a few countries, namely, Brazil, Columbia, Ecuador, Peru, India, Mexico, Zaire, Madagascar, Australia, China, Indonesia and Malaysia THE HIERARCHY OF CLASSIFICATION-GROUPS Ernst Haeckel (1894), Robert Whittaker (1959) and Carl Woese (1977) classified all living organisms into broad categories called kingdoms. Whittaker proposed classification that has 5 kingdoms : Monera, Protista, Fungi, Plantae and Animalia They are formed on the basis of : cell structure, mode and source of nutrition and body organisation. Woese modified this classification by introducing division of Monera into Archaebacteria (Archae) and Eubacteria (Bacteria) Further classification is done by naming the subgroups at various levels : Kingdom Phylum (Animals) / Division (Plants) Class Order Family Genus Species The basic unit of classification is species. Species includes all organisms that are similar enough to breed and perpetuate.Monera These organisms are prokaryotic They are unicellular Some organisms have cell wall while others don't They are autotrophic or heterotrophic. Examples : bacteria, blue - green algae or cyanobacteria, mycoplasma, anabaena. Protista unicellular eukaryotics some have appendages, such as hair like cilia or whip-like flagella for moving around autotrophic / heterotrophic examples : unicellular algae, diatoms, protozoans ( paramecium, amoeba and euglena ) Fungi Euaryotic Heterotrophic and Saprophytes Multicellular / Unicellular Have cell walls made up of a tough complex sugar called chitin Examples : Yeast, mushrooms, aspergillus, agaricus, penicillium Some fungal species live in permanent dependent relationships blue-green algae Lichen is the symbiotic association between fungi and blue-green algae Plantae is further divided into sub-groups on the basis of the following : whether the plant body has well differentiated, distinct components whether they have vascular tissues or not whether they have the ability to bear seeds if they bear seeds, whether they are enclosed within fruits