Unit 1. Diversity in the living world
Chapter 1.
THE LIVING WORLD
• BIOLOGY: - The word biology was taken from Greek. Bio means life, logy means study of. Therefore biology means study of life.
• The branch of science, which deals with the study of structure, function, habitat and economic importance of organism is called biology.
• Aristotle was considered as father of biology.
• Life: - The living activity shown by an organism from birth to death is called life.
• Characteristics of living organism: -• Growth: The living things exhibit internal growth
or intersusception growth.
• Reproduction: During the life span all living organism reproduce themselves. Some organisms reproduce asexually & some sexually.
• Metabolism: The living organism have metabolism. The total sum of chemical reaction occurs in side the organism is called metabolism.
• It is classified into 2 types.
1. Anabolism
2. Catabolism
• Anabolism: - It is the chemical reactions in which large molecules are builds from smaller components.
• These are constructive reactions.
• EX: photosynthesis
• Catabolism: - It is the chemical reactions in which break down of large molecules in to smaller components.
• These are distructive reactions • EX: Cellular respiration, in which glucose is
broken down in to CO2 & H2O.
• cellular organization: All living organism have cellular organization. The cell forms the structural and functional unit of life.
• The organisms having only one cell are called unicellular organisms. EX: amoeba, paramecium, euglena etc
• The organisms having millions of cells showing organ and organ systems are called multicellular organism. EX: All plants and animals.
’• Size: The livings organism have definite farm and
size.
• Consciousness: All living organisms show response to stimulus.
• They have interim relation with surrounding environment.
• Biodiversity : Term used to refer to the number of varieties of plant and animals in region on earth.
• Need for classification : living organisms are classified into categories because that could be named, remembered, studied and understood.
• Nomenclature: Binomial nomenclature was first introduced by Carolus Linnaeus. He published the book ‘Systema Naturae’.
• The scientific naming of an organism using two words is called Binomial nomenclature.
• Each scientific name has two components - Generic name + Species name.
• Rules for Nomenclature : 1. Latinised names are used.2. First word is genus, second word is species
name.3. Printed in italics; if handwritten then underline
separately.4. First word starts with capital letter while species
name written in small letter.Ex: Mangifera indica.( mango)
• ICBN : International Code of Botanical Nomenclature (for giving scientific name to plants.)
• ICZN : International Code of Zoological Nomenclature (for giving scientific name to animals.)
• Taxonomy : Study of principles and procedures of classification.
• Systematics : It deals with classification of organisms based on their diversities and relationships among them. Term was proposed by Carlous
• Taxonomic Hierarchy : It is the arrangement of various taxa of classification
• Species → Genus → Family → Order → Class → Phylum (for animals) Division (for plants) →Kingdom
• SPECIES: Group of individuals having fundamental similarities in characteristics and successful reproduction takes place among themselves form a species.
• E.g:Panthera tigris,Panthera leo • Solanum tuberosum, Solanum nigrum.•
• GENUS : • It consists of a group of related species.
Genera are aggregates of closely related species.
• E.g:Panthera leo ,P pardus (leopard) ,P tigris
• FAMILY
• It has a group of related genera.• E.g:family Solanaceae includes genera
solanum(tomato,potato) , petunia & datura. • Family Felidae includes genera panthera
(lion, tiger ,leopard) &Felis(cat)
• ORDER:• It is the group of families which include a few
similar characters. • E.g:order polynomial includes family solanaceae &
convovulaceae. • E.g: carnivora includes family felidae &
cancidae(dog) .
• CLASS :• It includes all related orders having few similar
characters. . • E.g: class mammalia includes order Primata
(monkey, gorilla,gibbon) &carnivora. • E.g:class Dicotyledonae includes order
polymoniales &sapindales(mango)
• PHYLUM or DIVISION:• It includes related classes having few similar
characters. • E.g:phylum Chordata includes classes
fish ,amphibia, reptilia, aves &mammalia. • Division angiospermae includes class
dicotyledonae & monocotyledonae.
• TAXONOMICAL AIDS:• Taxonomic studies of various species of plants,
animals and other organisms require correct classification and identification.
• Identification of organisms requires laboratory and field studies.
• The other taxonomical aids are,• Herbarium• Botanical Garden• Museum• Zoological Park
• Herbarium is a store house of collected plant specimens that are dried, pressed and preserved on sheets.
• Museums have collections of preserved plant and animal specimens.
• Zoological Parks are the places where wild animals are kept in protected under human care.
• Key• Key is another taxonomical aid used for
identification of plants and animals based on the similarities and dissimilarities.