BIOLOGY: The Living World


Characteristics of Living Organisms : Growth, reproduction, metabolism, cellular organization, consciousness (ability to sense environment), self-replicating and self regulation.
• Reproduction and growth are NOT defining properties.
• Metabolism, cellular organization and consciousness are defining properties.


Term used to refer to the number of varieties of plant and animals on earth.
Nomenclature: standardize the naming of living organism such that a particular organism is known by the name all over the world.
Identification: nomenclature or naming is only possible when the organism is described correctly and we known to what organism the name is attached to.
Need for classification: To organize the vast number of plants and animals into categories that could be named, remembered, studied and understood.

Rules for Nomenclature

1.Latinized names are used, written in italics
2.First word represents the 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.

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.
Binomial Nomenclature: Given by Carolus Linnaeus. Each scientific name has two components – Generic name + Specific epithet.
Systematics: It deals with classification of organisms based on their diversities and relationships among them. Term was proposed by Carolus Linnaeus who wrote ‘Systema Naturae’.

Taxonomic Hierarchy: Arrangement of various steps (categories or taxa Species → Genus → Family → Order → Class → Phylum (for animals) /Division (for plants) Kingdom→


All the members that can interbreed among themselves and can produce fertile offsprings are the members of same species. This is the bio-logical concept of species proposed by Mayer.
Three Domains of Life: Proposed by Carl Woese in 1990 who also proposed the six kingdom classification for living organisms. The three Do-mains are Archaea, Eubacteria and Eukarya.



Storehouse of dried, pressed and preserved plant specimen on sheets.
Botanical Garden: Collection of living plants for reference.
Taxonomical aids: Zoological Park (Places where wild animals are kept in protected environment.)

• Keys (Used for identification of plant and animals on the basis of similarities and dissimilarities.)
• Fauna: (Index to animal species found in a particular area)
• Flora (Index to plant species found in a particular area.)
• Manuals (Provide information for identification of name of species in an area.)
• Monograph (Contain information on one taxon.)