Living World PDF

Summary

These notes cover characteristics of life, growth, reproduction, and defining features for living organisms. It includes descriptions of different types of reproduction, unicellular and multicellular organisms, and the importance of nomenclature in classifying and understanding different organisms.

Full Transcript

# 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|

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