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L AB.1 Introduction - Biological diversity and its classification - Plant nomenclature Kingdom: BACTERIA Phylum: Eubacteriophyta Class: Eubacteriae Class:Cyanobacteriae Lab manual :pp. 1-3 Biological diversity: Definition: Sum total of all living things in a given space. Our planet has 40 million species of which only about 2 million species are identified and named to this date. 300,000 species are members of Kingdom Plantae 65,000 species are members of Kingdom Protista 99,000 species are members of Kingdom Fungi 10,500 species are members of Kingdoms Bacteria and Archaea Without plants, there is no life They are the only source of food and oxygen for the whole world, which they produce through the process of photosynthesis. Therefore, the functioning of the planet, and the survival of mankind and all other living things, depend upon plants. Owing to the large number of species and their diversity, it is necessary to classify them, in order to study and manage them better. Classification of organisms: All known living organisms are categorized in six kingdoms based on: - The structure of the body - Mode of nutrition - Mode of reproduction These six Kingdoms are : Archaea, Bacteria, Protista, Fungi, Plantae and Animalia The major categories of plant classification in a decending hierarchical order are: Kingdom, phylum, class, order, family, genus and species. There can be additional categories in between. • Example of classification of onion: Kingdom: Plantae Phylum: Magnoliophyta Class: Liliopsida Order: Liliales Family: Amaryllidaceae Genus: Allium Species: Allium cepa Genus Specific epithet Scientific naming Binomial Nomenclature Rules of Binomial nomenclature: In 1753, Carl Linnaeus (Swedish biologist) started using this system of naming the species and it is continued to the present day. 1. The scientific (Latin) name of the species has two parts: • First part is the genus name. • The second part is the specific epithet. Scientific name = Genus name + specific epithet 2. Scientific names are always written in Latin and follows the rules of that language. The two parts together represent the name of the species e.g., Allium cepa or Allium cepa = Onion The name should be written in italics or underlined. Rules of Binomial nomenclature 3. No two species can have the same name 4. The specific epithet may be descriptive 5. The name of the genus is always capitalized, specific epithet is not 6. The genus name can be used alone, but the specific epithet cannot stand alone 7. The name of the author is combined with the binomial to make it more authentic, especially in scientific publications. E.g.: Allium cepa L. (Onion) Kingdom Bacteria Prokaryotic Cells : Genetic material and other organelles are without membranes. Prokaryotic organisms are separated into two kingdoms: Archaea and Bacteria They differ in the chemistry, metabolism and RNA molecules of the cells. ◦ Kingdom Archaea : methane bacteria, salt bacteria, sulfolobus bacteria. ◦ Kingdom Bacteria: all the other known bacteria. Owing to their many similarities, only Kingdom Bacteria is dealt with in the lab exercises. Features of the Kingdom Bacteria Prokaryotic Cells Cells are : - Unicellular - Colonies or chains - Filaments Cell wall material - No cellulose. Features of the Kingdom Bacteria Nutrition Most bacteria are heterotrophic (saprophytes and parasites). Food is usually absorbed through the cell wall or membrane. Some bacteria have symbiotic association with other organisms. Some are autotrophic 1. Chemosynthetic (obtain their food and energy through chemical reactions). 2. Photoautotrophic (their cells contain chlorophyll, enabling them to make their food by photosynthesis) Reproduction Asexual reproduction: 1- Binary fission: the division of a single cell into two or more resembling the original. 2- Formation of spores: Spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavorable conditions. New wall growing inward in a dividing bacterial cell Kingdom: Bacteria Phylum : Eubacteriophyta Class : Eubacteriae (True bacteria) Class : Cyanobacteriae (The Blue-Green Bacteria) Kingdom: Bacteria Phylum: Eubacteriophyta Class Eubacteriae Commonly known as true bacteria. Some true bacteria are autotrophic, some are heterotrophic (saprophytes and parasites). Nutrition is by absorption of food in solution through the cell wall. Some true bacteria are very useful to man (e.g. in composting, diary industry), while some others are harmful causing various diseases (e.g. Anthrax, Cholera, Leprosy, Tetanus, Tuberculosis, Typhoid) Classification of Bacteria is based on several features. One main feature used to classify bacteria is cell shape Form 1. Cocci (coccus or spherical shape) 2. Bacilli (rod or cylindrical shape) 3. Spiral or helical Copyright slideshare.net Kingdom: Bacteria Phylum: Eubacteriophyta Class: Eubacteriae Genus: Bacillus Unicellular Rod-shaped or cylindrical shaped bacteria 1. Bacillus (rod or cylindrical shape) Kingdom: Bacteria Phylum: Eubacteriophyta Class: Eubacteriae Genus: Streptococcus Coccus or spherical (round) cells forming a chain 2. Streptococcus (coccus or spherical shape) Kingdom: Bacteria Phylum: Eubacteriophyta Class: Eubacteriae Genus: Spirillum Spiral or helical-shaped cells 3. Spirillum (spiral or helical shape) Kingdom: Bacteria Phylum: Eubacteriophyta Class: Eubacteriae Genus: Sarcina Cuboidal cells forming 3-dimensional structures 4. Sarcina (cuboid shape). Source: Graphic design by A. Al-Arbash Kingdom: Bacteria Phylum: Eubacteriophyta Class: Eubacteriae Genus: Rhizobium Rhizobium cause the root nodules in leguminous plants.. This coccus-shaped bacterium is established inside the root nodules of legumes (Fabaceae). The relationship between the plant and the Rhizobium is beneficial (useful) for both organisms (symbiotic). Rhizobium fix atmospheric nitrogen and provide it to the plant as nitrates and nitrites that helps the plant to grow better. Root nodules provide protection and nutrients to the bacterial cells. 5. Rhizobium Legume Plant root root nodules Kingdom: Bacteria Phylum: Eubacteriophyta Class: Cyanobacteriae They are known as blue-green bacteria ◦ Cyanobacteria are autotrophic and produce their food by photosynthesis ◦ Pigments in Cyanobacteria:- Chlorophyll a (green color), - Phycobilins (phycocyanin - blue, phycoerythrin - red) and carotenoids (yellowish). Kingdom: Bacteria Phylum: Eubacteriophyta Class: Cyanobacteriae Body forms : unicellular, colonial to filamentous forms. Their body is usually covered by a moist, gelatinous sheath. Many filamentous forms have the ability to fix atmospheric nitrogen into nitrogenous compounds like ammonium, nitrate and nitrites, in a structure known as heterocyst. Hence are beneficial to farmers who use them to enhance the growth of their crop plants. Kingdom: Bacteria Phylum: Eubacteriophyta Class: Cyanobacteriae Genus: Gloeocapsa It is unicellular organism, covered with a gelatinous sheath, that keeps the cell surface moist and helps the cells to unicellular glide. It forms a false colony produced by binary fission, within the gelatinous sheath. Occasionally the sheath breaks open releasing the unicellular organisms. 6. Gloeocapsa (unicellular) gelatinous sheath Kingdom: Bacteria phylum : Eubacteriophyta Class : Cyanobacteriae Genus : Merismopedia http://www.7bscience.com/ The body consists of a one-cell gelatinous sheath thick false colony. Ellipsoidal cells are arranged in Ellipsoidal cells arranged in columns columns. Cells are surrounded by a gelatinous One cell thick false colony sheath. 7. Merismopedia (colonial) Kingdom: Bacteria Phylum : Eubacteriophyta Class : Cyanobacteriae Genus : Oscillatoria gelatinous sheath Necredium Hormogonium •Filamentous body structure interrupted with necredia (dead cells) •The necredia (dead cells) are weak points in the filament where a segment of the filament (=hormogonium) can break and detach. •Each filament consists of several vegetative cells arranged in a line and enclosed by a gelatinous sheath. End cells are rounded. 8. Oscillatoria (filamentous with dead cells) Kingdom: Bacteria Phylum : Eubacteriophyta Class : Cyanobacteriae Genus : Anabaena Filamentous with rounded cells Akinete is a structure that is formed under unfavorable conditions . It also aids in asexual reproduction. Heterocyst is a thick-walled structure that helps in fragmentation and nitrogen fixation. Anabaena is used by farmers to enrich the soil and enhance plant growth (provide fixed nitrogen). 9. Anabaena (filamentous with heterocysts and akinetes) Vegetative cells akinete heterocyst