Environment

1. In simple words, environment is defined as the natural world in which people,
animals and plants live. The term Environment is derived from French terms
‘virer (to turn) or ‘in/viron’ meaning to encircle; and denotes the interaction
between natural surroundings and organisms including human beings. Thus,
environment is the surroundings in which living and non-living things live,
interact, grow and perish. The conditions present in the surroundings govern
the life of creatures therein.
The Four Spheres of The Earth

2. The four spheres of the Earth.
 The four spheres of the Earth are: the lithosphere, hydrosphere,
biosphere, and atmosphere
 The biosphere includes all living life on Earth: animal, plant,
fungi, protist and Monera
 All four spheres must work in harmony to allow for the balance of life
to succeed of Earth. Any threat to one sphere, will have drastic effects
on the others.
The earth can be split into one of four major subsystems, namely: land, water,
air, and all living things. These categories are known as spheres, and are the
lithosphere, hydrosphere, atmosphere and biosphere, respectively. The first
three of these spheres are abiotic, meaning they are not living things, while the
fourth - the biosphere - contains all biotic, or living creatures and organisms
(everything from plants, to animals, to bacteria).
Atmosphere
The atmosphere of Earth, which we casually refer to as simply ‘air’, is actually
made up of a mixture of gases and vapours. The Earth’s atmosphere forms
a

3. barrier, or bubble around the Earth, and is held there by the force of gravity.
This keeps the vapours of the atmosphere from escaping into outer space. It is
also this atmosphere which makes the earth inhabitable. The combination of
chemicals in the air, as well as the way in which the atmosphere creates a
barrier between the Earth and the harmful rays of the sun, makes an
environment in which animals, plants and human life can thrive.
The layers of the Earth's atmosphere.
The atmosphere can be separated and identified in several of its own layers, of
which there are 5: the troposphere, stratosphere, mesosphere, thermosphere
and exosphere. The Troposphere is the layer which holds the majority of the
atmosphere and is closest to the surface of the earth. This is also the area in
which most organic life lives, on Earth. The other layers extend outward from

4. the surface, and are encompassed by the last layer, the Exosphere, before our
atmosphere completely dissolves into Outer Space.
The atmosphere of Earth is actually primarily made from nitrogen, with a
composition of 78 percent. The second most common gas in our atmosphere is
Oxygen, which makes up 21%, and is the most important for both human and
animal life. The third most prominent gas is argon, which is only 0.9 percent.
This leaves the remaining 01. percent, which is classified as ‘other’ as no one
gas is dominant enough to be significant. However, this ‘other’ section does
include water vapor, neon, carbon dioxide, and methane.
Hydrosphere
Water cycle allows the hydrosphere to function.

5. The hydrosphere is the water sphere of Earth. This includes the total amount of
water that can be found on the whole planet, from that on the surface - like in
lakes, oceans, rivers etc. as well as water underground, and in the air. Because
it includes all water, this also means that it encompasses water that is found in
liquid, vapor, or solid (i.e., ice) form.
Liquid
The first type of water most commonly thought of, is liquid water. This can be
seen in a variety of places and forms across the earth. Everything from lakes
and seas, to streams, lagoons, rivers, creeks and springs are forms of liquid
water which connect to form the hydrosphere. There is also an entire system of
underground water that is also in liquid form. This water is usually accessed via
aquifers, natural springs or wells. The underground water system is known as
the water table and contains all types of water that has become trapped below
the surface. Groundwater fills the spaces between sediment and rock, creating
pockets of trapped water. Often, these pockets are tapped by humans via

6. pipelines and wells, but in some cases the water naturally finds its way to the
surface via springs and the like. This natural water source is also extremely
useful for large plant life like trees, that need considerably more water than that
which they can absorb through rain and atmospheric moisture.
Vapor
Water vapor is any type of water that has evaporated, and now takes on a
gaseous state. This includes things like fog and clouds. Water vapor forms an
integral part of the water cycle. When liquid water evaporates, it turns into a
gas, and becomes part of the atmosphere. Here, it can be redistributed into
other parts of the world. For example, a puddle - liquid - can be dried up in the
sun, forcing the water molecules to change and evaporate. Now, in gas form,
they form a cloud. This cloud is then blown through the air, where it collects
more moisture until the cloud becomes so heavy with water vapor that the
vapor becomes liquid again, falling back to the earth’s surface as rain.
Solid

7. Water in its solid form can be seen on earth as ice. This includes everything
from the polar ice caps to frozen lakes and bays, frost, snow, glaciers, and
icebergs. This protein of the hydrosphere can actually be subsection into what
is known as the cryosphere. While the cryosphere may not be the first thing
associated with water and the hydrosphere in general, it does play an important
part in the larger system. It helps to regulate the global climate and is home to
a variety of animals which rely on this frozen world to live.
Lithosphere
Layers of the lithosphere.
The lithosphere is the ‘earth’ or land portion of the Earth. It more specifically
refers to the rocky outer surface of the Earth’s crust, and upper portion of the
mantle. The Earth itself is split into several layers: the crust, upper and main
mantle, the outer core and the inner core. Though all of this is Earth, it is
only

8. the more solid upper portion that is included in the lithosphere. This means it
is the generally solid, minimally viscous portion, as opposed to the more liquid
molten lower layers. The lithosphere is the land on which biological life - i.e. the
biosphere - exists.
Biosphere
Illustration of the hierarchy of biological organization.
The biosphere is the sphere of the earth which includes all organic, living
life.
Whether this life is on the earth’s surface, in the atmosphere, or below
the

9. ground, it is part of the larger biosphere system that makes up life on this
planet. In this way, the biosphere blends with the other three spheres of Earth.
The range of the biosphere is thought to be roughly 20 kilometers, or 12 miles
from its highest point, to its deepest. Generally speaking, though, most of the
Earth’s life is much closer to the surface and can be found within about 500
meters or 1,640 feet below sea level, and 6 kilometers, or 3.75 miles above the
ocean’s surface.
From the tallest mountain to the deepest ocean, all organic life is part of the
biosphere. This includes all types of life, from insects to fungi, animals and
birds, plants and organisms like bacteria. This life is then divided into a series
of classifications: kingdoms, phylum, classes, orders, families, genus, and
species. There are 5 different kingdoms, known as: animal, plant, fungi, protist
and Monera, and all of these encompass the entirety of the biosphere. The
large biosphere is then further broken down into biomes and ecosystems,
which are more specific working systems of animals and plants in any given
area. Together, they form an intricate web of life which, when kept in balance,
allows our Earth to run in harmony.