Sixth Semester Notes (Botany) Kashmir University Free Pdf Download


Environmental factors
Environment may be defined as the surrounding of a living organism. With the realization of
a direct interference of man with environment and vice versa, environment also encompasses
the social and cultural forces of human society. Environmental factors are external forces
either living or non-living that affect the life of the organisms. The non-living environment
can further be classified into atmosphere, lithosphere and hydrosphere, whereas biotic
environment is called biosphere. Environmental factors are substances (soil, rock, water, air),
conditions (light, temperature, humidity, rainfall), forces (wind, gravity), and organisms
(plants, animals, microorganisms, human being). Broadly the environmental factors are
classified as:
1. Climatic factors: These factors denote the long term average weather conditions of a place
for examples temperature, precipitation, wind, humidity, fog, cloud cover and atmosphere
2. Physiographic factors: These include the factors of physical geography of earth such as
latitude, longitude, altitude, terrain, angle of slope and aspects.
3. Edaphic factors: These include processes related to the formation of soil and physical,
chemical and biological characteristics of soil.
4. Biotic factors: These factors denote all kinds of influences caused by living organisms
including man
Environmental factors do not act individually, but many factors interact to influence the
existence and success of an organism, known as interaction of environmental factors. The
intensity, importance and time scale of factors, however, vary with organisms and ecosystem
Climatic Factors
Climate is a product of weather, which is day-to-day condition of light, temperature,
precipitation, humidity, and wind and air pressure. Climatic factors are mainly concerned
with aerial environment of organisms. Following are important climatic factors.
Solar radiation
The sun makes all life on earth possible. It provides habitable temperature, otherwise the
average temperature of the planet would approach -33O C when all water would be frozen.
Sun’s energy is utilized by photosynthetic organisms to convert in food molecules required
by almost all forms of life. The amount of solar radiation that reaches a point just outside the
earth’s atmosphere (at a height of 83 km) measured perpendicular to the sun’s rays is known
as solar constant. Solar constant is estimated as 1.98 langley min-1 or 1.94 cal cm-2 min-1

WhatsApp Group Join Now
Telegram Group Join Now

Leave a Comment