Living World and Classification of Microbes PDF

1. Living World and Classification of Microbes 1. What is the hierarchy for classification of living organisms? Can you recall? 2. Who invented ‘bionomial system’ of nomenclature? 3. Which levels of hierarchy are considered while w...

1. Living World and Classification of Microbes 1. What is the hierarchy for classification of living organisms? Can you recall? 2. Who invented ‘bionomial system’ of nomenclature? 3. Which levels of hierarchy are considered while writing the name in binomial nomenclature? Biodiversity and need of classification Last year we learnt that all the living In History...... organism on earth have adapted according to Carl Linnaeus in 1735 divided geographic regions, food ingestion, defence etc. living world in 2 kingdoms - While adapting, many differences are observed Vegetabilia and Animalia. in the organisms of same species too. Haeckel in 1866 considered 3 According to 2011 census, around 87 million kingdoms- Protista, Plants and species of living organisms are found on the Animals. earth- including land and sea. To study such a In 1925 - Chatton created vast number, it was essential to divide them into two groups Prokaryotes and groups. So groups and subgroups were created Eukaryotes. considering the similarities and differences In 1938 Kopland divided living among the living organisms. organisms into 4 kingdoms- This process of dividing living organism Monera, Protista, Plants and into groups and subgroups is called Biological Animals. classification. Robert Harding Whittaker (1920-1980) was an American Ecologist. In 1969 he divided living organisms into 5 groups. For this classification Whittaker considered following criteria 1. Complexity of cell structure : Living Organisms Prokaryotic and Eukaryotic. 2. Complexity of organisms : Prokaryotes Eukaryotes Unicellular or Multicellular. 3. Mode of nutrition : Plants - Autotrophic- Unicellular Unicellular Multicellular Photosynthetic Fungi- Saprophytic- Absorption Kingdom1. Monera Kingdom 2. Protista from dead organisms. Animals- Heterotrophic and ingestive. Kingdom 3. Kingdom 4. Kingdom 5. 4. Life style : Fungi Plantae Animalia Plants - Producers Cell wall Cell wall present No cell wall Animals - Consumers present and organisms Fungi - Decomposers but organisms can performs can’t perform photosynthesis 5. Phylogenetic relationship : photosynthesis. Prokaryotic to Eukaryotic, unicellular to multicellular. 1.1 Five Kingdom system of classification 1 11  Clostridium tetani Vibrio choleri Try this Treponema pallidum Kingdom 1 : Monera Streptococcus Activity : Take a small drop of curd or pneumoniae buttermilk on a clean glass slide. Dilute it with a little water. Carefully keep a Legionella cover slip. Observe it under high power of pneumoniae Salmonella compound microscope. What did you see ? typhi Moving, small rod-like microbes are lactobacilli bacteria. Staphylococcus Clostridium All type of bacteria and blue green algae aureus botulinum are included in the kingdom Monera. Characteristics : 1. All the organisms are unicellular. 1.2 Organisms from Kingdom Monera 2. They may be autotrophic or heterotrophic. 3. These are prokaryotic cells without distinct nucleus or cell organelles Kingdom 2. Protista Activity : Prepare a temporary mount of one drop of pond water on a glass slide. Paramoecium Observe it under low power and high power Volvox of microscope. You will find some motile microbes with irregular shape. These are amoebae. Characteristic : 1. Protista are single celled organisms with Euglena Amoeba well defined nucleus enclosed in a nuclear 1.3 Organisms from Kingdom Protista membrane. 2. They have pseudopodia or hair like cilia or whip like flagella for locomotion. Sporangium 3. Autotrophs- eg. Euglena, Volvox contain chloroplast. Columella Heterotrophs- eg. Amoeba, Paramoecium Kingdom 3. Fungi Apophysis Activity : Take a moist piece of bread or bhakri and keep it in a container with lid for Hypha Sporangiophore 2-3 days. After 2-3 days a fine cotton thread like tuft is found growing on the surface of the bread. Prepare a temporary mount of Rhizoids few threads from this culture and observe it under the microscope. 1.4 Fungi Institutional Work : National Institute of Virology, Pune is involved in research on viruses. This institute has been founded in 1952 under the jurisdiction of Indian Council of Medical Research. 2 12 Characteristics : 1. These are non-green, eukaryotic, heterotrophic organisms. 2. Most of them are saprotrophs. They feed upon decaying organic matter. 3. Their cell wall is made up of tough and complex sugar called ‘Chitin’. 4. Some fungi are thread like and many nuclei are present in the cytoplasm. 5. Examples- Baker’s yeast, Aspergillus (Fungus on corn), Penicillium, Mushrooms. Though many systems of classification are introduced after the Whittaker's, his five kingdom system is widely accepted. Use your brain power Explain merits and demerits of Whittaker’s classification. Classification of Microbes Among the living organisms, microorganisms are largest in number. Hence they are classified as follows. 1.5 Some Fungi Microorganisms With reference to size of microbes, remember- 1 meter = 106 micrometer (mm) Prokaryotes Eukaryotes 1 meter = 109 nanometer (nm) Bacteria Protista Fungi Algae 1.6 Classification of Microorganisms 1. Bacteria (size – 1 mm to 10 mm) 1. Unicellular, independent / parasitic Coccus organisms. Sometimes many bacteria together form colonies. 2. Bacterial cell is prokaryotic with cell wall, Cocco-bacillus but distinct nucleus or cell organelles are absent. Spirillum 3. They reproduce by simple binary fission. 4. In favourable conditions, bacteria grow Bacillus vigorously and can double their number in 20 minutes. Vibrio (Comma shaped) 1.7 Some Bacteria 3 13 2. Protozoa (size - approximately 200 mm) 1. Protozoans are found in soil, fresh water and sea water. Some are found in the body of other organisms and are pathogenic. 2. These are unicellular organisms with eukaryotic cell. 3. There is great variation in cell structure, organs of locomotion and modes of nutrition among protozoans. Paramoecium 4. These organisms reproduce by simple cell division. Eg.- Amoeba, Paramoecium - Free living in dirty water. Entamoeba histolytica - causes amoebiasis. Plasmodium vivax- causes malaria Euglena - autotrophic 3.Fungi- (size- approximately 10 mm to 100 mm) 1. These are found on decaying organic matter and dead bodies of plants and animals. Entamoeba 2. These are eukaryotic organisms. Some are unicellular and others are visible with naked eyes. 3. Saprotrophic, absorb their food from decaying organic matter. 4. They reproduce sexually and asexually by cell division or by budding. Eg. Baker's yeast, Candida, Mushroom. 4. Algae- (size- approximately 10 mm to 100 mm) Plasmodium 1. They are aquatic. 2. Eukaryotic, unicellular, autotrophic organisms. 3. Photosynthesis is carried out with the help of chloroplast present in the cell. Eg. Chlorella, Chlamydomonas very few species of algae are unicellular. Most of them are multicellular and visible with naked eyes. 5. Viruses-( size- approximately 10 nm to 100 nm) Saccharomyces Generally, viruses are not considered as living organisms or they are said to be “Organisms at the edge of living and nonliving.” They are studied under microbiology. 1. Viruses are extremely minute i.e. they are 10 to 100 times smaller than bacteria and can be seen only with electron microscope. Chlorella 2. They are found in the form of independent particles. Virus is a long molecule of DNA (Deoxyribo Nucleic Acid) or RNA (Ribo Nucleic Acid) covered by a protein coat. 3. Viruses survive only in living plant or animal cells and produce their own proteins with help of host cell and create their numerous replica. Then they destroy the host cell and become free. These free viruses again infect new cells. 4. Viruses cause many diseases to plants and animals. Tomato Wilt Virus 1.8 Some Microorganisms 4 14  Do you know? Internet My Friend Human – polio virus, Influenza virus, HIV – AIDS virus etc. Collect pictures and Cattle- picorna virus characteristics of different Plants- Tomato- Wilt virus, Tobacco mosaic virus etc. microbes. Prepare a chart. Bacteria- Bacteriophage (viruses attack bacteria). Exercises 1. Use Whittaker method to classify b. Write the characteristics of viruses. bacteria, protozoa, fungi, algae, c. Explain the nutrition in fungi. prokaryotic and eukaryotic microbes. d. Which living organisms are included in the kingdom monera ? 2. Complete the five kingdom method of classification using- living organism, 6. Who am I ? prokaryotes, eukaryotes, multicellular, a. I don’t have true nucleus, cell organelles unicellular, protista, animals, plants, or plasma membrane. fungi. b. I have nucleus and membrane bound cell orgenelles. Living organisms c. I live on decaying organic matter. d. I reproduce mainly by cell division. e. I can produce my replica. f. I am green, but don’t have organs. 7. Draw neat and labelled diagrams. Unicellular Unicellular a. Different types of bacteria. b. Paramoecium c. Bacteriophage. 3. Find out my partner 8. Arrange the following in ascending order A B of size Bacteria, Fungi, Viruses, Algae. Fungi Chlorella Project : Protozoa Bacteriophage 1. Prepare a chart showing infectious Virus Candida bacteria and the diseases caused by them. Algae Amoeba 2. Visit a nearby pathology lab. Get the Bacteria Prokaryotic information about pathogenic microbes, methods to observe them, different 4. State whether the following statements microscopes from the technicians there. are true or false. Explain your statement. a. Lactobacilli are harmful bacteria. b. Cell wall of fungi is made up of chitin. c. Organ of locomotion in amoeba is pseudopodia. e. Tomato wilt is a viral disease. 5. Give answers. a. State the merits of Whittaker’s method of classification. 5 15