Living World PDF

# Living World ## Characteristics of Life - Might be absent in some living organisms - Doesn't define life - Can be seen in living things 1. Growth 2. Reproduction ## Defining Feature - Which defines life. - Compulsorily present in all living organisms without exception - Shall be absent in n...

# Living World ## Characteristics of Life - Might be absent in some living organisms - Doesn't define life - Can be seen in living things 1. Growth 2. Reproduction ## Defining Feature - Which defines life. - Compulsorily present in all living organisms without exception - Shall be absent in non-living things - Ex. 1. Cellular organisation 1. Organisation 2. Metabolism 3. Consciousness ## Growth - All living organisms grow - Non-living things do not grow - Growth is the increase in mass - Increase in no. of cells - Both unicellular and multicellular organisms grow by cell division. - Plant - Growth is continuous, occurs throughout life - Animals - Growth is up to a certain age - Non-living things also show growth - Growth is not a defining feature of life ## Reproduction - Production of new individuals (progeny) by parents which are more/less similar to parents - Types: - Asexual Reproduction - Identical offspring: - **Fragmentation:** filamentous algae, fungi, protonema of mosses - **Spore formation:** fungi - **Budding:** yeast, Hydra - **Regeneration:** Planaria - Sexual Reproduction - Offsprings variations - In unicellular organisms, growth and reproduction are mutually inclusive events. - **Cell division (cell No. 1) = Growth = Reproduction** - In multicellular organisms, growth and reproduction are mutually exclusive events *Some Human Couples, Sterile worker bees, Mule can't reproduce but are living. Reproducion is not a defining feature of life* ## Defining Features ### 1. Cellular Organisation - **Cell:** Structural & functional unit of life - **Organisms:** - Unicellular - Multicellular *Viruses - Acellular: Non-living ### 2. Metabolism - Sum total of all the metabolic reactions that are occupying inside cell. - Anabolic Rxn - Catabolic Rxn - Rxn taking place outside cell are 'living Rxn' and not living things. ### 3. Consciousness - Most obvious feature of a living organism - Ability to sense the environment and respond to it - Ability to be aware of surroundings. - Only Humans - Self Consciousness # Diversity in the Living World - Different organisms around us - different species - Living world - includes million of species - **IUCN:** International Union for Conservation of Nature and Natural Resources. - According to IUCN - 1.7 - 1.8 million species are known & described yet. - Large area species - More diversity (1.7-1.8 million species) - Smaller area - less diversity (This is our Biodiversity.) - Each organism is known by its local name which varies from place to place. - Local names create confusion. - **Need:** Standardisation of names so that each organisms is known by one name all over the world. - **Naming of an organism - Nomenclature** ## Authority - Rules and Recommendation - **Plant:** ICBN: International Code for Botanical Nomenclature - **Animal:** ICZN: International Code for Zoological Nomenclature. - **Bacteria:** ICNB: International Code for Nomenclature of Bacteria - **Virus:** ICVCN: International Code for Viruses Classification & Nomenclature - **Cultivated Plant:** ICNCP: International Code for Nomenclature of Cultivated Plants. ## Nomenclature - The that deals & naming of an organism. - Binomial Nomenclature - Trinomial Nomenclature - Important points for Binomial Nomenclature. - **Gate given by Carolus Linnaens.** - **Book - Systema Nature** - Certain rules and regulations is to be followed for naming an organism. - Each organism should have only one scientific name - Names are in latin/latinised/derived from latin - Binomial - one name with two components. - Ex: Mango - Mangifera Indica - 1st word - Genus - 2nd word - Species (specific epithet) - When handwritten - It should be underlined separately. Ex: Mangifera indica - When printed - Italicized to indicate latin origin. - 1st letter of the Genus-should be Capital - 1st letter of the species - should be small (lower case). - Author's name - Ex: Mangifera indica Linn; This plant species -1st described by linnaeus - Author's name: - After species - Abbreviated form - Non underlined/not italicized - Principle of priority: - 1st name - valid name - Later name - synonym. - Ex: Tomato - Lycopersion esculentum (valid name) - Solanum lycopexsiacum (synonym) - **Trinomial Nomenclature:** - Plant - Ex: Babool - *Acacia nilotica nilotica* - Genus, species, variety - Animal - Ex: Human: *Homo sapiens sapiens* - Genus, species, subspecies ## Classification - Millions of species present on earth - Need of classification to understand and study them. - **Process** - anything is grouped into convenient category. ## Taxonomy - **Group/Category:** 'Taxon' - **Taxonomy:** Not a single step process. It involves a hierarchy of steps. - **Taxonomy:** The science which deals with describing, naming and classification of organisms. ### 4 Basic Processes (CICN) - **Characterisation:** Describing observable characters of an organism. - **Identification:** Try to identify organism by comparing its charcteristics with existing organisms/groups. - **Classification:** Try to put this organism into convenient categories. - **Nomenclature:** Name given according to binomial nomenclature. ### Types of Taxonomy - **Classical Taxonomy (Conventional):** Based on morphological features. - **Modern Taxonomy:** Based on external and internal features: - Cell Structure, Developmental process, Ecological information of organism. - **Systrematics:** - Systematics: Arrangement of an organism. - Taxonomy + phylogeny (evolutionary relationship of an organism) ## Taxonomic Categories - **Obligate Taxonomic Categories** - Kingdom - Phylum/Division - Class - Order - Family - Genus - Species - **Intermediate Categories** - **Species:** - Natural population of individual which show similar morphological characteristics and can freely interbreed in nature to produce fertile offsprings. - Ex: - Mango - *Mangifera Indica* species - Potato - *Solanum tuberosum* species - Tiger - *Panthera tigris* species - 3 species - 1 genus - Leo - *Panthera* - Pardus - *Panthera* - Tigris - *Panthera* - 2 genus - *Solanum tuberosum* (Potato) - *Melongena* (Brinjal) - *Nig nigrum* (Makoi) - **Genus** : Aggregate of similar species. Species of same genus show more similiarity in comparism to species of another genus. - **Family:** Group of related genera. - **Plant Family:** Vegetative and reproductive characteristics - Suffix: 'aceae' - 2 genera -> 1 family - *Panthera* -> *Felidae* - *Felis* -> *Felidae* - *Solanum*, *Petunia*, *Datura* -> Family *Solanaceae* - **Order:** Aggregate of related families. - Family *Felidae* -> Order *Carnivora* - Family *Canidae* -> Order *Carnivora* - Family *Solanaceae* (Potato fam) -> Order *Polymoniales* - Family *Convolvulaceae* (Sweet Potato fam) -> Order *Polymoniales* - Suffix: Plant -> 'ales' Animal -> 'X' - **Class:** Group of similar orders - Plant: - *Polymoniales, Sapindales* -> Class: *Dicotyledonae* - *Mango* - Animal: - *Carnivora, Primata* -> Class: *Mammalia* ## Phylum/Division - Class *Mammalia* - Class *Amphibia* - Class *Reptile* - Class *Aves* - *Phylum:* Chordate - Class *Dicotyledonae* - Class *Monocotyledonae* - *Division:* Angiospermae - 11 phyla -> Kingdom: *Animalia* - 5 Division -> Kingdom: *Plantae* # Table 1.1 Organisms with their Taxonomic Categories | Common Name | Biological Name | Genus | Family | Order | Class | Phylum/Division | |---|---|---|---|---|---|---| |Man|Homo sapiens|Homo|Hominidae|Primata |Mammalia|Chordata| |Housefly|Musca domestica|Musca|Muscidae|Diptera |Insecta|Arthropoda| |Mango|Mangifera indica|Mangifera|Anacardiaceae|Sapindales|Dicotyledonae|Angiospermae| |Wheat|Triticum aestivum|Triticum|Poaceae|Poales| Monocotyledonae|Angiospermae|