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Biological Classification, , , , , , , , , , , , , , , , @) INTRODUCTION, _ | There have been many attempts to Classify living organisms since the dawn of Civilisation. Aristotle was the earliest to attempt a more, , | | Scientific basis for classification He used simple morphological characters to classify plants into trees, shrubs and herbs. He also Pe, | divided animals into two gropus. with RBCs and without RBCs. Many of them five in or on other ad ite, They are grouped under four categories based on th, spherical (Coccus), rod shaped (Bacillus), comma shaped (, spiral shaped (Spirillum). es ork, ARCHAEBACTERIA :, Are special bacteria since they live in some of the harsh habitats, , as extreme salty areas (halophiles) hot springs (thermoacidophiles), and marshy areas (methanogens). Ae, , Have different cell wall structure than other bacteria. This feature is, responsible for their survival in extreme conditions., , Methanogens produce methane and found in gut of ruminant animals., EUBACTERIA or True Bacteria, Cyanobacteria (Blue green algae), e Maybe unicellular, colonial or filamentous,, fresh water/marine or terrestrial., e Have chlorophyll a similar to green plants., e Are photosynthetic autotrophs., Mycoplasma ., e Smallestliving known cells., e Can survive without oxygen. ~, . © Completely lack cell wall., e Are pathogenic to both plants and animals., , , , , , , , , , , , , , , , , , , , , , , , (2) TWO KINGDOM CLASSIFICATION SYSTEM, Given by Linnaeus., , Organisms were divided into two kingdoms Plantae, and Animaiia., , Disadvantages: This system did not distinguish between, _ | eukaryotes and prokaryotes, unicellular and multicellular, , @) FIVE KINGDOM CLASSIFICATION SYSTEM, » Given by R.H. Whittaker., , > All organisms were divided into five kingdoms, Monera, Protista, Fungi, Plantae and Animalia., , > Fungi were placed in separate kingdom called, kingdom fungi., , , , , , , , , , , , , , , , o, , , , , , , , , , , , , , , °, , , , °, , °, , , , , , , , , , , Present, (cellulose), , , , , , , , , , , , , , , , , , , , , , , , , , , o, , , , c . Five Kingdoms, mae [7 “Wonere_[Protsts [Fungi [Plantae | Animate |, Cell type Prokaryotic Eukaryotic Eukaryotic, Cell wall | Noncellulosic Present in Present with, | (Polysaccharide+ some chitin, amino acid), Nuclear Present Present | Present, membrane, || Body Cellular Cellular Multicellular/ | Tissue/ Tissue/organ/, Organisation loose tissue organ organ system, iti i Autotrophic Heterotrophic | Autotrophic, (Photosynthetic) | (Saprophytic/, and Heterotrophic | Parasitic), , , , Heterotrophic, (Photosynthetic)} (Holozoic/, , Saprophytic, etc., , , , , , , , , , , , , , 2 Bacteria are simple in structure but very complex in behaviour., 2 Show most extensive metabolic diversity. :, 2 Majority of bacteria are heterotrophic but can be photo or, chemoautotrophic. f, , - 9 Chemosynthetic autotrophs oxidise various inorganic substances, and play great role in recycling nutrients like nitrogen., , Heterotrophic bacteria: Majority are decomposers and arehelpful in making curd from milk, production of antibiotics, fixing. t, nitrogen in legumes etc. ee, poe are oe cause disease like cholera, typhoid, i as anus,, , , , , , , , , , , , , , , , 2 farlier classification systems included bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and, angiosperms under plants due to presence of cell wall., , 2 Chlamydomonas and Spirogyra were placed under algae., , 2 Kingdom Protista put together Chalamydomonas, Chlorella with Paramoecium and Amoeba., , ° Over time, an attempt has been made to evolve a classification system which reflects not only the, morphological, physiological and reproductive similarities but also phylogenetic i.e. is based on evolutionary, relationships. , :, , , , , , °
