Living World Notes PDF

Living World © 2022, Aakash BYJU'S. All rights reserved Key Takeaways Living vs non-living 1 2 Metabolism 3 4 Taxonomy © 2022, Aakash BYJU'S. All rights reserved Reproduction 5 Nomenclature Systematics 6 7 Taxonomic aids 8 Summary © 2022, Aakash BYJU'S. All rights reserved Taxonomic categories Livin...

Living World © 2022, Aakash BYJU'S. All rights reserved Key Takeaways Living vs non-living 1 2 Metabolism 3 4 Taxonomy © 2022, Aakash BYJU'S. All rights reserved Reproduction 5 Nomenclature Systematics 6 7 Taxonomic aids 8 Summary © 2022, Aakash BYJU'S. All rights reserved Taxonomic categories Living vs Non-living Growth is the increase in size, mass or height of an organism. This occurs by cell division. Animals grow only up to a certain age. In the later years, there is only replacement and repair of worn out cells. Hence their growth is termed definite. Plants, on the other hand, can grow throughout their lifetime. Thus, the word indefinite is used for growth in case of plants. o For example: The Great Banyan Tree in AJC Bose Indian Botanical Garden in West Bengal is 250 years old and is spread across 14,500 m2. © 2022, Aakash BYJU'S. All rights reserved Living vs Non-living In unicellular organisms, growth and reproduction are synonymous. In plants and animals, growth and reproduction are two separate phenomena. Living organisms grow due to addition from inside, also called intrinsic growth. Growth can be extrinsic too as seen in non-living matter by the accumulation of material on the surface. o Sand dunes and glaciers are good examples of extrinsic growth. Growth is a property of living beings but cannot be considered as a defining characteristic of living beings. © 2022, Aakash BYJU'S. All rights reserved Reproduction Production of new individual organisms or offspring by their parents Not essential for survival of individual but essential for the survival of a species Types of reproduction Asexual reproduction Sexual reproduction Does not involve the fusion of gametes Involves the fusion of gametes Offspring identical to the parent Offspring varies genetically from the parents Asexual reproduction is uniparental Sexual reproduction is generally biparental © 2022, Aakash BYJU'S. All rights reserved Asexual Reproduction Spore formation in fungi Fungi multiply and spread easily due to the millions of asexual spores they produce. These are quite resistant structures and do not damage easily. Budding in yeast Regeneration in flatworms Fragmented parts of organism regenerate the lost part of their body and becomes new organism. Binary fission in bacteria New individuals form from outgrowths (buds) on the bodies of mature organisms. Most common form of reproduction in prokaryotes and a few unicellular eukaryotes. Examples : Yeast and Hydra Example: Bacteria and Amoeba. © 2022, Aakash BYJU'S. All rights reserved Metabolism Catabolism Anabolism  Sum total of all the chemical reactions occurring in a coordinated manner to support life is called metabolism.  Occurs in both unicellular and multicellular organisms.  Non- living objects do not perform metabolic processes. Smaller units Energy Molecules Energy Smaller units Catabolism  Molecules are broken down and energy is released  E.g. - breakdown of food during digestion. © 2022, Aakash BYJU'S. All rights reserved Molecules Anabolism  Energy is utilised to combine smaller molecules to yield larger, more complex molecules.  E.g. – photosynthesis. Important Points Reproduction   All living beings cannot reproduce ○ Infertile couple : Inability of a couple to become pregnant and produce an offspring. ○ Worker bee : Amongst a swarm of bees, the worker bee is sterile while only the queen bee is fertile. ○ Mule : Cross between male donkey and female horse; doesn’t produce gametes. Hence, reproduction is not a differentiating character between living and nonliving organisms. © 2022, Aakash BYJU'S. All rights reserved Metabolism  Chemical reactions performed in a test tube are neither living nor non-living.  Metabolic reactions performed outside can be referred to as living reactions but not living things. Cellular Organisation  All living beings are made up of cells. ○ Cells aggregate to form tissues which in turn aggregate to form organs.  Each cell, further, consists of several organelles.  Organelles interact with each other for the proper functioning of the cell. It is a very organised process.   Each organelle may be involved in individual function. The functions performed by cells are a result of cumulative activities of all the organelles. Thus, cellular organisation is a defining property of living beings. © 2022, Aakash BYJU'S. All rights reserved Organ Tissue Cell System Organism Consciousness  It is the state of awareness of the surroundings and response to external stimuli.  Examples are: ○ Sense organs ○ Photoperiod  All cells (prokaryotes to eukaryotes) respond to external factors. ○ Example: Folding of leaves in Mimosa pudica (Lajwanti or chhuimui) occurs due to external stimulus of touch.  Consciousness is a defining property of living organisms. Note Human beings in coma have no self-consciousness. They are supported by machines. Some come back to normal life, some don't. It is difficult to define the living state in such cases, living or non-living or dead. © 2022, Aakash BYJU'S. All rights reserved Nomenclature  About 1.7 - 1.8 million species on Earth have been identified and described.  Biodiversity is the term used to describe the enormous variety of life on Earth.  Identification is the process by which the features or characteristics of an organism are known, so that one can identify the organism in any part of the world.  Identified organisms are named in accordance with a standard procedure, accepted all across the world. This is called nomenclature. © 2022, Aakash BYJU'S. All rights reserved Nomenclature Binomial nomenclature  Most accepted system  Given by Carolus Linnaeus ○ Known for two works, namely Species Plantarum (1753) for plants and Systema Naturae (1758) ○ In Systema Naturae, using the binomial nomenclature system, Carolus named 4,400 animal species and 7,700 plant species ○ Two terms are used to denote a species of living organism in this system: Generic name - E.g. - Mangifera Specific epithet - E.g. - indica o Eg: Mangifera indica (Mango) © 2022, Aakash BYJU'S. All rights reserved Nomenclature  Uses Single scientific name to replace multiple vernacular names.  Description of any organism enables people to arrive at the same name.  Ensures that a name has not been used for more than one known organism. Rules of binomial nomenclature  Biological names are generally in Latin. They are Latinised or derived from Latin irrespective of their origin.  The first word in a biological name represents the genus while the second component denotes the specific epithet.  Both the words in a biological name, when handwritten, are separately underlined, or printed in italics to indicate their Latin origin.  The first word denoting the genus starts with a capital letter while the specific epithet starts with a small letter. o E.g. : Mangifera indica © 2022, Aakash BYJU'S. All rights reserved Nomenclature    There are 2 major codes for naming organisms: ○ International Code for Botanical Nomenclature (ICBN) for naming plants. ○ International Code of Zoological Nomenclature (ICZN) for naming animals. Note Animal species having the same name for both genus and species are known as tautonyms. Examples : Eurasian eagle owl (Bubo bubo), European grass snake (Natrix natrix). © 2022, Aakash BYJU'S. All rights reserved Taxonomy  Scientists have grouped organisms into convenient categories based on their characters. This process is called classification of organisms.  Taxon is a group of one or more populations of an organism or organisms. It can refer to any category in the hierarchy of classification system.  Taxonomy is the branch of study that deals with principles and procedures of identification, characterisation, classification and nomenclature of organisms.  Based on characteristics living organisms can be classified into different taxa.  Earliest classifications were based on the ‘uses’ of various organisms such as, a. Basic needs of food - small animals like rabbit, deer, carrot, apple. b. Clothing - hides of animals, leaves from trees. c. Shelter - coconut leaves, bamboo, etc - to build homes.  Earliest classification system was not very efficient. © 2022, Aakash BYJU'S. All rights reserved Taxonomy Basis of modern classification: External characteristics Development process © 2022, Aakash BYJU'S. All rights reserved Structure of cell Ecological information of organisms Taxonomy Steps involved in modern taxonomy a. Characterization - morphological and all other characters are described b. Identification - determining similarities with already known organisms c. Classification - placing the organism under a particular taxa or category d. Nomenclature - giving a proper scientific name © 2022, Aakash BYJU'S. All rights reserved Systematics  Systematics is the study of evolutionary relationships among organisms.  Derived Latin word ‘systema’ which means the systematic arrangement of organisms.  Study of one organism gives information about the whole group.  Taxonomy, systematics and classification are often used synonymously but technically are not the same. © 2022, Aakash BYJU'S. All rights reserved Specimen Taxonomy (Description) Classification (Arrangement) Nomenclature (Naming) Morphology (Terminology of parts) Taxonomic vs Systematics Taxonomy Systematics Process of classification Includes taxonomy and nomenclature Importance Identify, name, describe organisms Describes evolutionary relationships among organisms Abiotic conditions They are indirectly related They are directly related Change with time Subject to change with time Does not change with time Definition © 2022, Aakash BYJU'S. All rights reserved Taxonomic Categories SPECIES GENUS FAMILY ORDER CLASS PHYLUM KINGDOM © 2022, Aakash BYJU'S. All rights reserved  It is also called the Linnaean hierarchy/ taxonomic hierarchy as it was first proposed by Linnaeus.  A taxon is a group of organisms and a category represents the rank of the taxon. Taxonomic Categories Kingdom  It is the highest category of classification in which certain common fundamental characters are used as the basis of classification.  For example: Kingdom Animalia comprises organisms that are multicellular, heterotrophic and eukaryotic. R.H Whittaker came up with a 5 kingdom classification that is widely accepted today. Monera Protista © 2022, Aakash BYJU'S. All rights reserved Fungi Plantae Animalia Taxonomic Categories Phylum  A phylum is a category below Kingdom, where classification is based on common features. Kingdom Plantae  Organisms in a phylum share the same set of characteristics which distinguishes them from another phylum. Division Thallophyta  The same category is called division in the Kingdom Plantae. Algae Fungi Sub-division © 2022, Aakash BYJU'S. All rights reserved Taxonomic Categories Class  This is the category below phylum.  Category between phylum and class is subphyla.  For example : Kingdom animalia > phylum chordata > subphylum vertebrata (has notochord) > Class pisces and aves.  Human beings fall under the class Mammalia. © 2022, Aakash BYJU'S. All rights reserved Order  This is the category which comes below class. A group of closely related orders forms a class.  For example: Kingdom animalia > phylum chordata > subphylum vertebrata (has notochord) > superclass tetrapoda (bears limbs) > class mammalia > order primate or primates.  Another example is : Order Carnivora comprises flesh eating animals like tiger, cat and dog. Taxonomic Categories Family  This category is below order.  A group of closely related families forms an order.  Genus It is the category below family and forms the first word of a scientific name.  Category below family but above genus is a sub-family.  A group of closely related species forms a genus.  For example: Kingdom animalia > phylum chordata > subphylum vertebrata (has notochord) > superclass tetrapoda (bears limbs) > class animalia > order primate > family hominidae > sub family hominidae > genus homo © 2022, Aakash BYJU'S. All rights reserved Species  It is the lowest category of classification and forms the second word of a scientific name. Taxonomic Categories Example of taxonomic categorisation Benefits of taxonomy Kingdom Animalia  Categorisation of organisms for ease of study. Phylum Chordata  Compares similarities and differences between organisms. Sub Phylum Vertebrata  Shows evolutionary relationships.  Same name is used for an organism worldwide  Knowledge of bioresources and their diversity Class Mammalia Order Primate Family Hominidae Genus Homo © 2022, Aakash BYJU'S. All rights reserved Taxonomical Aids Herbarium Botanical garden  It is a collection of plant specimens that are dried, pressed and preserved on sheets.  They are specialised gardens with collections of living plants.  The description on the sheet: a. Date and place of collection b. English, local and botanical names c. Family name d. Collector’s name  Plant species are also grown for identification purposes.  Plant is labelled indicating : 1. Botanical/scientific name 2. Family  It is a repository for future use. © 2022, Aakash BYJU'S. All rights reserved Taxonomical Aids Museums  Collections of preserved plant and animal specimens    Zoological parks  Specimens are used for study and reference. Wild animals are kept in protected environments under human care.  Generally, set up in educational institutes Food habits and behaviours of the animals are studied.  The animals are provided with their natural living conditions. Specimens are preserved in the containers with preservative solutions. © 2022, Aakash BYJU'S. All rights reserved Taxonomical Aids Catalogue   List which methodically enumerates all species found in a particular place is called catalogue. Monograph  Manual Complete global record of a taxon is called a monograph. © 2022, Aakash BYJU'S. All rights reserved Records that provide information of species found in an area are called manuals Key     It is a tool that helps to identify an unknown organism. Keys provide two contrasting characteristics which are called couplets. Each statement in the key is called a lead. Separate taxonomic keys are required for each taxonomic category. Summary Types of reproduction Sexual reproduction Asexual reproduction Non-identical offspring Identical offspring Spore formation Budding Binary fission Metabolism Catabolism © 2022, Aakash BYJU'S. All rights reserved Anabolism Regeneration Summary Characteristics of living organisms Reproduction Metabolism Cellular organisation Consciousness Growth 5 Kingdom classification R.H Whittaker came up with a 5 kingdom classification that is widely accepted today. Monera Protista © 2022, Aakash BYJU'S. All rights reserved Fungi Plantae Animalia Summary Steps of modern taxonomy 1.Characterization 3. Classification 2. Identification 4. Nomenclature Taxonomic categories SPECIES GENUS FAMILY ORDER CLASS PHYLUM KINGDOM © 2022, Aakash BYJU'S. All rights reserved Summary HERBARIUM KEYS MONOGRAPH MANUAL TAXONOMICAL AIDS MUSEUM CATALOGUE ZOOLOGICAL PARK BOTANICAL GARDEN © 2022, Aakash BYJU'S. All rights reserved