Biological Classification PDF

Biological classification Kingdom System of Classification First scientific attempt for classification was performed by Aristotle. Aristotle used simple morphological characters to classify plants into herbs, shurbs and trees.... And animals into anaima (without rbc) & ena...

Biological classification Kingdom System of Classification First scientific attempt for classification was performed by Aristotle. Aristotle used simple morphological characters to classify plants into herbs, shurbs and trees.... And animals into anaima (without rbc) & enaima (with rbc) Carolus Linnaeus gave two kingdom classification :- plantae & animalia He classified based on the following criterias :- 1. Cell wall 2. Locomotion 3. Mode of nutrition 4. Response to external stimulus 5. Contractile system (vacuole) It does not distinguish B/w :- (i) Unicellular & multicellular organisms (Ii) Eukaryotes & Prokaryotes (IiI) Photosynthetic (green algae) & non-photosyntehtic (fungi) (Iv) Chlamydomonas, euglena & slime moulds behave as both plants & animals Ernst haeckel gave three kingdom classification including protista (aquatic eukaryotes) (also known as dustbin kingdom due to irregular boundaries)  Copeland gave four kingdom classification including monera (prokaryotic organisms) RH Whittaker (1969) gave five kingdom classification including Fungi. He classified based on the following criterias :- 1. Cell structure (prokaryotic or Eukaryotic) 2. Thallus (body) organisation 3. Mode of nutrition 4. Reproduction 5. Phylogenetic (evolutionary) relationship 6. Nuclear membrane ⭐⭐ Chlamydomonas, spirogyra, chlorella, paramaecium & amoeba were placed together under kingdom protista. Carl woese proposed six kingdom classification separating monera into archaebacteria & eubacteria on the basis of absence of peptidoglycon & occurrence of branched chain lipids.  Based on 16S ribosomal rna genes, woese gave three domains of life :- 1. Archae 2. Bacteria 3. Eukarya - includes protista, fungi, plantae & animalia ⭐⭐Monera was divided into two domains of life :- archae & bactera Kingdom : monera All are unicellular prokaryotes. Monera shows maximum nutritional diversity. First inhabitants of the earth. Bacteria are the sole diversity of this kingdom. Characteristics :- 1. They can live in extreme habitats such as hot springs. 2. They are unicellular, colonial or filamentous. 3. Nucleoid is composed of naked ds circular dna, rna & histone proteins. 4. Cell wall is made up of peptidoglycon (amino acid + sugar) except archaebacteria & mycoplasma. 5. 70s ribosome. 6. Organelles absent. 7. Asexual reproduction. 8. Respiratory enzymes are associated with plasma membrane. 9. Shows both heterotrophic & autotrophic nutrition. Shapes of bactera 1. Coccus - spherical shaped (micrococcus) 2. Bacillus - rod shaped (lactobacillus) 3. Vibrio/vibrium - comma shaped (vibrio cholera) 4. Spirillum - spiral shaped (pseudomonas) Respiration Both aerobic & anaerobic respiration. 1. Obligate/strict aerobes - can live only in the presence of oxygen. Eg. Bacillus subtilis 2. Obligate/strict anaerobes - Can live only in the absence of oxygen. Eg. Clostridium botulinum 3. Facultative aerobes - can respire both anaerobically & aerobically (in the presence of O2). Eg. Chlorobium 4. Facultative anaerobes - they normally respire aerobically but can switch over to anaerobic to get energy for survival. Eg. Pseudomonas Nutrition Divided on the basis of primary source of carbon, energy, electron & pigments. 1. Photosynthetic autotrophic bacteria (A) Photo-lithotrophic bacteria : Trap solar energy and use for synthesis of food. Due to pigments :- bacteriochlorophyll, bacteriopurpurin, bacterioviridin. ⭐ ⭐ Purple sulphur bacteria ( thiospirillum, chromatium ) :- contains bacteriopurpurin pigment & uses inorganic sulphur compounds (hydrogen sulphide, thiosulphate) as electron & h+ donor. ⭐ ⭐ Green sulphur bacteria ( chlorobium limicola ) :- contains bacterioviridin pigment and uses h2s as electron & h+ donor.  In bacterial photosynthesis, water is not the source of electron. Therefore, it is anoxygenic. (B) Photo-organotroph : Purple non-sulphur bacteria (rhodospirillum) uses non sulphur aliphatic organic compounds as e- & h+ donor. Green non-sulphur bacteria (chloronema) also uses non sulphur aliphatic organic compounds. Most of the photosynthesic bacteria are anaerobes (facultative aerobes). 2. Chemosynthetic autotrophic bacteria Do not utilise light as energy source. Synthesize food by oxidising inorganic substances. Play a great role in recycling nutrients like nitrogen, phosphorus, iron, sulphur, etc. [LEVEL - 2] (A) Nitrifying bacteria NH3 —> N2 Eg. Nitrosomonas, nitrococcus No2 —> no3 Eg. Nitrobacter, nitrocystis (B) Iron bacteria Eg. Ferrobacillus, leptothrix (C) Hydrogen bacteria Eg. Hydrogenomonas (D) Sulphur bacteria Eg. Beggiatoa, thiobacillus thioxidans [Level - 2 ends] 3. Heterotrophic bacteria Most abundant in nature. Majority are decomposers. Saprophytes :- free living bacteria which obtains nutrition from dead & organic remains Symbiotic :- mainly gram -ve & capable of fixing atmospheric n2. Eg. Rhizobium - associated with the roots of legume plants. While azatobactor, klebsiella & beijerinckia are aerobic and fix n2 in free state, whereas clostridium is anaerobic n2 fixing bacteria. Parasitic :- obtain nutrition from living organic host (either plants or animals). Reproduction Mainly asexual but can show sexuAl recombination (true sexual reproduction is -nt) 1. Asexual Most common - Binary fission Under unfavourable conditions, there is endospore formation - contains calcium dipicolinic acid which makes endospore most resistant. Under favourable conditions (nutrient availability, moisture and temperature), daughter cells repeat binary fission and increase population but stops due to :- 1. Space shortage 2. Accumulation of waste products 3. Development of Bacteriophage 4. Lack of nutrients. # Binary fission is amitotic type.  Involves 3 steps :- 1. Replication of dna 2. Mesosome division & cytoplasmic membrane formation :- mesosome begins to divide due to synthesis of membrane b/w dna-mesosome attachment sites. 3. Cross wall formation :- [septum & cross wall formation occurs simultaneously] 2. Sexual/genetic recombination :- No gamete formation & fusion Only exchange of genetic material takes place b/w bacterial cells It includes :- (A) Transformation :- Method of genetic recombination without direct contact b/w 2 bacterial cells. Discovered by "Griffith" Experimented on - Diplococcus & streptococcus pneumonia Competence - ability of bacterial cells to pick up dna from the surrounding. (B) Conjugation :- Method in which bacterial cells come in Direct contact. Discovered by lederberg & tatum. (plasmid was also discovered by them) Experimented on :- e-coli (C) Transduction :- Method via Bacteriophage. Discovered by zinder & lederberg. Experimented on :- SalmonellA typhimurium  Types of bacteria 1. Archaebacteria Primitive bacteria/oldest living fossil Can survive in extreme conditions due to diff cell wall structure consists of [NAT] & branched chain lipids.(decreases memb. Fluidity) They have introns in their genetic sequence. (A) Methanogens Present in marshy habitats & in guts of several ruminant animals. Responsible for the production of methane. Chemoautotrophs & obligate anaerobes Eg. Methanococcus, methanobacterium (B) Halophiles Live in extreme saline environment. Heterotrophs Develop bacterio-rhodospin pigment in presence of sunlight(also +nt in our eyes) to harness sun's energy. Eg. Halobacterium, halococcus (C) Thermoacidophiles Can tolerate temp upto 80°C & ph as low as 2. Found in hot water springs. Facultative anaerobes & chemosynthetic in nature. Eg. Thermoplasma, thermoproteus 2. Eubacteria/true bacteriA Cyanobacteria Gram -ve photosynthesic prokaryotes. Most primitive organisms to have oxygenic photosynthesis. Added oxygen to the atmosphere. Also known as bga (blue green algae) & are classified under cyanophyceae & myxophyceae. Mainly lives in freshwater. Anabaena azollae is associated with azolla. Anabaena cycadae is associated with caralloid roots of cycas. When they live endozoically in protozoans, they are called cyanelle. They are characterized by absence of flagellum throughout the life cycle. ⭐⭐Trichodesmium erythrium imparts red colour to sea⭐⭐ ⭐⭐Most self dependent organisms⭐⭐ Biological nitrogen fixation is an anaerobic process as it requires nitrogenase enzyme for n2 fixation which occurs in heterocysts (nostoc). Heterocysts (lack ps ii activities) - n2 fixation Vegetative cells - co2 fixation Reproduction Asexual (binary fission, fragmentation, heterocysts, hormogonia, akinetes) Typical sexual reproduction -nt. Importance Played major role in evolution. Death & decay of these increases soil fertility. Tolypothrix & aulosira fix n2 symbiocally in rice fields. Nostoc & anabaena used for reclaiming usar soils. Benefit the partner by providing nitrogenous compounds.  Spirulina is edible, non toxic fast growing cyanobacterium cultivated in tanks as source of protein rich animal food. Microcystis aeruginosa & anabaena flos-aquae causes algal blooms & secrete toxins which are harmful to aquatic organisms (causes death) Forms Unicellular :- spirulines (binary fission) Filamentous :- nostoc (fragmentation) - accidental Colonial :- anabaena (daugter colony formation) Heterocysts :- germinates & form new under unfavourable. Mycoplasma Discovered by e. Nocard & e.r. roux (1898) from pleural fluid of cattles. Nowak (1929) placed them under genus mycoplasma. Found in soil, sewage water & infects both plants & animals. Can pass through bacterial filter (not a bacteria) Can also multiply in abiotic medium (not a virus) Heterotrophic mode of nutrition. Some are also saprophytic & parasitic. ⭐⭐ M. Gallisepticum - smallest parasite (0.3-0.5 um)⭐⭐ They are facultative anaerobes. Also known by the names :- 1. PPlo (pleuro pneumonia like organisms) 2. Jokers of plant kingdom 3. Mlo (mollicutes like organisms) 4. Bacteria with their coats off Therefore, bacterial structure is simple but the behaviour is complex. ⭐Bacteria shows most extensive metabolic activity⭐ Kingdom : protista This Kingdom forms a link between Kingdom Monera on one hand and other three kingdoms on the other hand. Protistans are the ancestors of all multicellular Eukaryotes. Protista are Unicellular Eukaryotes. Mostly aquatic. 80 s ribosomes & cell organelles +nt. 9+2 arrangement of cilia & flagella (tubulin protein) Both asexual & sexual reproduction. Life cycle by - zygotic meiosis & gametic meiosis Decomposers, photosynthesic or parasites. Photosynthetic/protistan algae constitutes major portion of phytoplanktons. 1. Diatoms (2n) Golden brown photosynthesic protists. Both aquatic & terrestial Possess various colours Unicellular, but may form pseudofilament & colonies. Lacks flagella except in the reproductive stage. Floats on the surface along the direction of water current. Therefore, also known as phytoplanktons. Cell wall is impregnated with silica & frustule (silicious particle) Cell wall appears like soap box. Pigments :- chl a, c, carotenoids & xanthophyll (dinoxanthin, diatoxanthin) Asexual reproduction (binary fission) Resting spores are called statospores. Reserve food :- chrysolaminarin Responsible for almost 50% of the total organic matter synthesized. Zygote formed during sexual reproduction is called auxospore. Even after the death of diatom, the shell comes at the surface of the water & these rock-like deposits form Diatomaceous earth/diatomite/kiseleguhr (used in filtration & polishing) Eg. Navicula, triceratium, melosora, cymbellA ⭐Very good indicator of water pollution⭐. ⭐Chief producers of ocean⭐. Dinoflagellates Golden brown photosynthesic protists. Mainly marine Unicellular, motile & Biflagellated Body is enclosed by theca or lorica Heterokont flagella :- longitudinal & transverse. Pigments same as diatoms Asexual & sexual reproduction (isogamous & anisogamous) Life cycle involves zygotic meiosis. Also shows bioluminescence (emits light) Eg. Noctiluca, pyrocystis Therefore, known as night light/fire algae/pyrophyte Gonyaulax/gymnodium produce saritoxin into sea which does not harm to shell fish but when consumed by humans causes paralytic shell fish poisoning (psp). Also known as armoured dinoflagellates & whirling whips. Euglenoids Unicellular, flagellate protists found in water or damp soil. Cell wall -nt but periplast or pellice is +nt Have long tinsel type flagella & one reduced flagella. Have photosensitive paraflagellar body. Perform creeping movement with the help of myonemes which is called metaboly/euglenoid movement. Stigma or an eye spot contains photosensitive red-orange pigment called astaxanthin. Photo autotrophic nutrition. Mixotrophic nutrition. Pigments same but instead of chl c, it contains chlorophyll b. Paramylon (reserve food) During unfavourable conditions, palmella stage & cysts are formed for perennation. Eg. Euglena, paranema  Slime moulds Usually free living. Creeps over debris like fallen leaves & logs of wood. Have naked protoplast. Under favourable conditions, they form plasmodium. Under unfavourable conditions, they form fruiting bodies. Spores are resistant and are dispersed by air currents. Both asexual & sexual reproduction. Eg. Physarum, physarella, dictyostellium, polysphondilium Forms connecting link with plants, animals & fungi :- 1. Fungi like feature - formation of fruiting bodies 2. Plant like - cell wall around spores 3. Animal like - plasmodium is without cell wall. Protozoan Locomotion Examples Disease Entamoeba Amoeboid Pseudopodia Dysentry histolytica Trypanosoma Sleeping Flagellated Flagella paladium sickness Ciliated Cilia Paramaecium Multiple Sporozoans Absent Plasmodium Malaria  Plasmodium is the most notorous causing malaria Kingdom : fungi (n) Cosmopolitan (present everywhere) Mostly present in warm & humid areas & terrestial. Shows great diversity. Forms :- 1. Corticolous (bark) 2. Coprophilous (cow dung) 3. Epixylic (wood) 4. Xylophilous (burnt wood) 5. Keratinophilous (keratin) Multicellular except yeast & synchytrium. Fungal body is made up of hyphae. Network of filaments (hyphae) is called mycelium. Cell wall of hyphae is made up of chitin or fungal cellulose Reserve food :- oil & glycogen Cells have unicistarnae golgi body. Heterotrophic nutrition. In vegetative phase, fungus is hidden & is hardly visible. After attaining maturity, it enters into reproductive phase. In Unicellular yeasts, both phase occurs. Eucarpic - when a part of mycelium is used in the reproductive structures. Holocarpic - when entire cell is used Reproduction 1. Vegetative :- Fragmentation Fission  Budding 2. Asexual :- Occurs through spores (mitospores) (A) Zoospore - uniflagellate (synchytrium) or Biflagellate (pythium, saprolegnia) Biflagellate :- -Primary zoospore (pear shaped/pyriform) -Secondary zoospore (kidney/bean shaped) (B) Sporangiospore Thin walled Non motile Under favourable condition, they produces endogenously in sporangium Eg. Rhizopus, mucor (C) Conidia Non motile Thin walled Exogenous spores produced at conidiophore. Eg. Aspergillus, penicillium (D) Chlamydospore Under unfavourable conditions, forms thich walled resting resistant spores Under favourable conditions, germinate to give rise to new ones. Eg. Rhizopus (E) Oidia Non motile Thin walled spores under sugar rich conditions Their budding stage is called torula 3. Sexual reproduction Occurs through oospores, ascospores & basidiospores which are produced in fruiting bodies. Ascospores - non motile & endogenous Basidiospores - non motile & exogenous It involves 3 steps :- 1. Plasmogamy (cytoplasm fusion) 2. Karyogamy (nucleus fusion) - in some, karyogamy is not done right after plasmogamy & this resting phase is called dikaryophase. 3. Meiosis (n) Plasmogamy (A) Planogametic copulation/gametic fusion (2n) :- fusion of two gametes of opposite sex. Eg. Allomyces Isogamy, anisogamy & oogamy (B) Gametangial contact :- two gametes come in contact through a fertilization tube but both gametes never fuse together losing their identity. Eg. Phythium, albugo (C) Gametangial copulation :- direct fusion of gametes with dissolution of walls resulting in single cell. Eg. Mucor, rhizopus (D) Spermatization :- some fungi produce spermatia on spermatiophores which are transferred to the female hyphae via water/air. Eg. Puccinia (E) Somatogamy :- gametes are absent. Direct fusion of hyphae. Eg. Agaricus