Biology_Today_-_October_2016

Biosphere

Biologically inhabited part of earth alongwith its physical environment consisting of lower atmosphere,

land and water bodies.

Biome

A large regional unit delimited by a specific climatic zone, having a particular major vegetation zone and

its associated fauna, e.g., tundra, desert, temperate deciduous forest, tropical rain forest.

Landscape

Unit of land distinguished by a natural boundary and having patches of different ecosystems, e.g.,

Southern Peninsula.

Flow chart: Ecological levels of organisation

ENVIRONMENT, WEATHER AND CLIMATE, HABITAT, NICHE

Environment

s It is the sum total of all biotic and abiotic factors, substances and conditions that surround and potentially influence organisms
without becoming their constituent part. Various components of environment are interlinked as well as interdependent.

Weather and Climate

s Weather is a short team property of the atmosphere such as heat, cold, wind, etc. whereas climate is a long term property of the
atmosphere.
Differences between weather and climate

It remains same over a long period of time

It does not change in such circumstances as it

represents the average of the factors and conditions

It determines the flora and fauna of a place

It is same over a larger area

Climate

It changes from place to place

It changes with changes in any of the atmospheric factors

and conditions

Changes in weather occur from time to time

Its changes have little impact on flora and fauna of a place.

Weather

Local variation of a climate in an area of limited size is called microclimate. Below a tree, temperature is higher than the

surroundings in winter while it is lower during summer. Canopy of tall trees is exposed to strong light and high temperature during

the day while plants occurring below them receive dim light, lower temperature and higher humidity.

Habitat
s Habitat is a specific place or locality delimited by a combination of factors, physical features and barriers where a community
resides, e.g., pond, desert, river, valley, saline soil, etc.

s Plants and animals adapt themselves to specific conditions of their habitat, e.g., aquatic organisms, halophytes.
s The characteristic adaptations related to a particular habitat are not found in organisms of another habitat, e.g., plants of saline
and non-saline soils.
s Due to large scale regional and local variations in each climatic and vegetational zone there are innumerable habitats on earth
e.g., scorching desert of Rajasthan, rain soaked Meghalaya forests, high mountain tops, deep sea trenches, permafrost polar
regions, boiling thermal springs.

s A habitat supports number of species and numerous ecological niches.

Niche
s Niche is specific part of habitat occupied by individuals of a species which is circumscribed by its range of tolerance, range of
movement, microclimate, type of food and its availability, shelter, type of predator and timing of activity.

s Tadpole and adult frog occupy different ecological niches as the former is herbivorous aquatic while the latter is carnivorous
amphibian.
s An ecological niche supports a single species. Each species occupies a distinct niche and no two species occupy the same niche.