Tiêu đề Biological Classification 4.0.pdf ✅

Biological Classification 1 Biological Classification Introduction Biological classification is the scientific method to classify the organism into different group on the basis of their similarities or dissimilarities. Criteria for classification has been changed with time because knowledge regarding organism is increasing. Overtime an attempt has been made to evolve a classification system which reflect not only the basic observable character but its phylogeny also. Different Biological Classification • Aristotle was the earliest to attempt a more scientific basis for classification. • This classification based on one or two morphological characters. Living organisms Plant Animal Herbs Shrubs tree Anaima animal without RBC Enaima animal with RBC (i) Two Kingdom Classification: • Given By Carolus Linnaeus • Mainly based on presence of cell wall, Locomotion & Mode of Nutrition. Living world Kingdom plantae Kingdom Animalia Cell wall present Locomotion absent Autotrophic mode of nutrition e.g. plant, bacteria, fungi Cell wall absent Locomotion present Heterotrophic mode of nutrition e.g. All animals from protozoa to mammals Demerits :- • Prokaryotic bacteria are placed in plantae along with eukaryotic plant and fungi. • Autotrophic plants are placed along with heterotrophic fungi in plantae. • Unicellular and multicellular organism are placed in same kingdom. e.g. Chlorella, Chlamydomonas and Spirogyra in plantae. • Plants with cellulosic cell wall were placed in plant alone with fungi. 2
2 Biological Classification (ii) Five Kingdom Classification: Given by R. H. Whittaker (1969) R.H. Whittaker (1969) proposed a five-kingdom classification. The main criteria used by him for making classification are:- (i) Cell structure (Complexity of cell) (ii) Thallus organization (complexity of organism)/Body organization (iii) Mode of nutrition (iv) Reproduction (v) Phylogenetic relationship Five Kingdom: 1. Monera: All the prokaryotes (Archaebacteria, Eubacteria, BGA, Mycoplasma) 2. Protista: All the unicellular eukaryotes (Dinoflagellates, Diatoms, Euglenoids, Slime moulds (false fungi) and Protozoans. 3. Fungi (mycota): True fungi 4. Plantae: All the multicellular plants - Algae, Bryophyta, Pteridophytes, Gymnosperm, Angiosperm 5. Animalia: All the multicellular animals Demerits :– • Virus, viroid, prions and Lichens are not included in five kingdom Classification.
Biological Classification 3 Table: - Characteristics of the Five Kingdoms Characters Five kingdoms Monera Protista Fungi Plantae Animalia Cell type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic Cell wall Nonecellulosic (Polysaccharide + amino acid) Present in some Present with chitin Present (cellulose) Absent Nuclear membrane Absent Present Present Present Present Body Organization Cellular Cellular Multicellular/ loose tissue Tissue/ organ Tissue/organ/ Organ system Mode of nutrition Autotrophic (chemosynthetic and photosynthetic) and heterotrophic (saprophytic/parasitic) Autotrophic (Photosynthetic) and Heterotrophic Heterotrophic (Saprophytic/ Parasitic) Autotrophic (Photosynthetic) Heterotrophic (Holozoic/ Saprophytic etc.) Six Kingdom Classification: • Three domain system has also been proposed that divided the kingdom monera into two domains i.e. Archaea & Bacteria • All remaining eukaryotic organisms in the third domain eukarya and there by a six kingdom classification. Carl Woese: He gave three domain theory. In these three domains 6 kingdoms are included. He suggested separate kingdom for Archaebacteria. It is based on 16S rRNA gene analysis. Living world Archaea Eukarya Archaebacteria Kingdome Protista Fungi (mycota) Plantae Animalia 3 Domains On the basis of sequence of rRNA Bacteria Kingdome Kingdome Eubacteria 1. Who used simple morphological attempt for classification of plants? (1) Linnaeus (2) Aristotle (3) Theophrastus (4) All 2. Which of the following kingdom classification is unable to distinguish between prokaryotes and eukaryotes, unicellular and multicellular? (1) Five kingdom (2) Four kingdom (3) Two kingdom (4) Three kingdom Concept Builder
4 Biological Classification 3. The criteria/criterias for five kingdom classification is: (1) Cell structure (2) Nutrition (3) Body organisation (4) All of the above 4. Carl Woese proposed: (1) Three-domain system (2) Five kingdom classification (3) Four kingdom classification (4) Two kingdom classification 5. Phylogenetic classification is mainly based on: (1) Evolutionary relationship (2) Morphological characterization (3) Morphological and anatomical features (4) All cellular character Que. 1 2 3 4 5 Ans. 2 3 4 1 1 Concept Builder (Answer-Key) Kingdom Monera (All Prokaryotes) Main characteristic of prokaryotes: - (1) Cell Wall: Cell wall of prokaryotes is made up of peptidoglycan. (2) Cell Membrane: (A) Like eukaryotes the cell membrane of prokaryotes is made up of lipoprotein [lipid + protein] (B) The space between cell wall and cell membrane is known as periplasmic space. (3) Cytoplasm: (A) The cytoplasm of prokaryotes lack membrane bound cell organelles. (B) In prokaryotic cell, the nucleus is indistinct. (C) In prokaryotes ribosomes (site of protein synthesis) are of 70S type. (D) In prokaryotes ribosomes are found in cytoplasm and associated with the plasma membrane of the cell. Examples of Prokaryotes (1) Archaebacteria (2) Eubacteria (3) Blue Green Algae (4) Mycoplasma Eubacteria Shape: • Bacteria show large variations in their shape. • On the basis of their shape bacteria are of different types. Coccus/Cocci • These Bacteria are spherical • These are the smallest bacteria • Maximum resistant bacteria e.g. Streptococcus pneumoniae Bacillus/Bacilli • This group includes most of the bacteria • These are rod- shaped e.g. E. coli, Bacillus vulgaris Spirillum/Spirilla • These are spiral shaped bacteria e.g. Spirillum volutans, Troponema Comma/Vibrio • These are comma shaped bacteria e.g. Vibrio cholerae