Biology_Today_-_October_2016





Class XII

Analysis of various PMTs from 2012-2016

2012

2013

2014

2015

2016

AIPMT/NEET

23136

AIIMS

112–1

AMU

3115–

Kerala

3–325

K.CET

––3–4

J & K

2–211

Organisms and Populations

s Ecology is the branch of biology concerned with the study of interrelation amongst
organisms and interaction with their environment.

s Term ecology was coined by Ernst Haeckel.

Synecology

Ecology that deals with group of organisms or

communities and study of environmental factors which

affect communities and populations.

Autecology

Ecology of individual species,their

requirements and interrelation with

the environment

Branches of Ecology

LEVELS OF ECOLOGICAL ORGANISATION

s Arrangement and coordination of small components into larger components in a
hierarchy, where each level is formed by components of lower level and itself becomes
constituent of higher level is called biological hierarchy.

Ecosystem

Segment of nature consisting of a biological community and its physical environment, both interacting

and exchanging materials as well as energy, e.g., pond ecosystem.

Population

Group of similar individuals in a particular geographical area or space.

Biotic Community

Assemblage of populations of different species of plants, animals, bacteria and fungi which live in a

particular area and interact with one another through competition, predation, mutualism, etc.

Individual

Basic unit of ecological hierarchy as it continuously exchanges materials and information with its

environment. It is distinct living entity which carries out all life processes in its body, separate from those

in other individuals. New individuals develop from pre-existing ones.