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.