Components of Environment = Four Sphere of Earth - Biosphere Atmosphere Lithosphere Hydrosphere

1. z
Submitted to : Dr. Manisha Yadav
Submitted by : Taruna Deshwal
M.Sc. 1ST Sem (ES)

2. FOUR SPHERES OF EARTH
Everything in Earth’s system is placed into one of
the four subsystems: land, water, living things, or
air.
The subsystems are known as “spheres.”
Specifically, they are known as the geosphere
(land), hydrosphere (water), biosphere
(living things) and atmosphere (air).

3. BIOSPHERE
The biosphere, which includes the
ground and the air, is characterized
as the region of the planet where
organisms live. The biosphere is
defined as the region on, above, and
below the Earth’s surface where life
exists.

4. COMPONENTS OF BIOSPHERE
The biosphere is the region of the Earth where
life can be found, including the soil, water, and
air. The lithosphere, hydrosphere, and
atmosphere are the names for these three
components. The lithosphere is the landmass of
the Earth, except for the mantle and core, which
are inhospitable to life.

5. ATMOSPHERE
 An atmosphere is a blanket of gases that
surrounds Earth. It is held near the surface of
the planet by Earth’s gravitational attraction.
 Definition
 “Atmosphere is a protective layer of gases that
shelters all life on Earth, keeping temperatures
within a relatively small range and blocking out
harmful rays of sunlight.”

6. Composition of Atmosphere – Gases in the
Atmosphere
 Argon, oxygen and nitrogen from the three main
constituents of the atmosphere.
 Dry air from earth’s atmosphere contains 0.038%
of carbon dioxide, 20.95% of oxygen, 78.08% of
nitrogen and 0.93% of argon.
 Traces of hydrogen, neon, helium, nitrous oxide,
ozone and other “noble” gases, but generally a
variable amount of water vapour is also present,
on average about 1% at sea level.

7. LAYERS OF ATMOSPHERE
The atmosphere has five distinct layers that are
determined by the changes in temperature that
happen with increasing altitude.
Layers of Earth’s atmosphere are divided into five
different layers as:
•Exosphere
•Thermosphere
•Mesosphere
•Stratosphere
•Troposphere

8. TROPSPHERE
 Tropo means turning or changing (there is more change in this layer than
any other)
 Lowest layer of atmosphere (closest to earth)
 Shallowest layer (thinnest)
 It is the layer we live in.
 Most of earth’s weather, such as clouds, storms, rain or snow, happens
here.
 Reaches approximately upto 11 kms above our heads.
 The temperature decreases (gets colder) as the altitude increases.

9. STRATOSPHERE
 Strato means layer or spread out .
 Second layer of atmosphere.
 Reaches from troposphere to about 5o kms above surface of earth
 Ozone layer is here (remember it protects living beings from UV radiation from
sun)
 Jets often fly here beacause it is calm.
 The temperature in the stratosphere rises, or gets hotter as the altitude increases.
 This heat is caused by ultraviolet light that is absorbed by the ozone layer.
 At the top of the stratosphere, it gets cold again.

10. MESOSPHERE
 Meso means middle
 Third layer of atmosphere
 Reaches from 50 km to 85 km above Earth’s surface.
 Protects Earth’s surface from being hit by meteoroids (chunk of stone and metal
from space – but some still get through).
 Most meteorites burn up within the Mesosphere because of friction with air
molecules.
 As the altitude increases, temperature decreases. At 85 km above Earth’s surface, it
is the coldest place in the Atmosphere.

11. THERMOSPHERE
 Thermo means heat, thermosphere got its name because of its
extreme heat.
 This layer absorb high solar radiation.
 Uppermost layer of the atmosphere.
 Thickest layer about 319 miles (513 kms)
 Reaches from 85 km above earth’s surface into outer space. There is
no definite upper limit.
 The thermosphere is home to the international space station as it
orbits earth. This is also where you’ll find low earth orbit satellites.
 As the altitude increases, temperature increases .
You would not feel warm here
.Why ?
If you were to hang out in the
thermosphere, though, you
would be very cold because
there aren’t enough gas
molecules to transfer the
heat to you.
This also means there aren’t
enough molecules for sound
waves to travel through.
It has two other layers :
IONOSPHERE AND EXOSPHERE

12. IONOSPHERE
 Lower layer of thermosphere
 Reaches from about 85 km to 400 km
above Earth’s surface
 Energy from the sun causes gas moleceules
here to become electrically charged
particles.
 Auroras happen near the poles because of
the ionosphere (these are the brilliant
streaks of light in night skies)
EXOSPHERE
 EXO means outer
 Outer portion of the thermosphere
 Reaches from about 400 km outward for
thousands of kilometers
 Space shuttles and satellites orbit Earth
here

14. Summary of Layers of Atmosphere
Region Altitude Range (km)
Temperature
Range(0oC)
Important
Characteristics
Troposphere 0-11 15 to -56
Weather occurs
here
Stratosphere 11-50 -56 to -2
The ozone layer is
present here
Mesosphere 50-85 -2 to -92
Meteors burn in
this layer
Thermosphere 85-800 -92 to 1200 Auroras occur here

15. LITHOSPHERE
 The term lithosphere refers to the Earth’s
rigid, rocky outer layer. It is made up of the
crust and the uppermost solid layer of the
mantle.
 Furthermore, it extends to a depth of about
60 miles. It disintegrates into a dozen
separate, rigid blocks or plates.

16. THE EARTH’S LAYER
The interior of the earth can be divided into 3 different
layers – crust, mantle, and core.
 Crust – The Earth’s outermost surface is called
the crust. The crust is relatively light and brittle.
Most earthquakes occur within the crust.
 Mantle - The mantle is relatively flexible so it
flows instead of fracturing.
 Core -
 Outer core –Fluid layer that contains iron. When
it flows it generates the Earth’s magnetic field.
 Inner core – Solid innermost layer of the Earth.

17. IMPORTANT TERMS
 LITHOSPHERE IS MADE UP OF THE CRUST AND THE MOHO
 Crust
The crust is typically about 25 miles thick beneath continents, and abut 6.5 miles
thick beneath oceans.
 Composition of Earth’s Crust
The earth’s crust is layered, with sedimentary rocks on top, granitic and metamorphic rocks
in the centre, and basaltic rocks at the bottom. A number of huge active tectonic plates
make up the earth’s crust.
 Moho
Mohorovic discontinuity is the dividing line between the crust and the mantle.
 Asthenosphere
The asthenosphere is the upper portion of Mantle.

18. THE CRUST
 The crust is the outermost solid part of the earth.
 The Earth’s crust is like the skin of an apple. It is very thin
compared to the other three layers.
 The crust makes up 1% of the Earth.
• It is fragile.
• The crust is made up of heavier rocks having a density of 3 g/cm3.
• The mean density of material in the oceanic crust is 2.7 g/cm3.
 The crust of the earth is broken into many pieces called plates.
• Silica (Si) and Aluminium (Al) are major constituent minerals. Hence it is
often termed as SIAL. Also, sometimes SIAL is used to refer to the
Lithosphere.

19. THE MANTLE
 The portion of the interior beyond the crust is called the mantle
 The mantle is the largest layer of the earth.
 It is in a solid-state.
 It has a density higher than the crust portion.
 The thickness ranges from 10-200 km.
 It is the chief source of magma that finds its way to the surface during volcanic eruptions.
 The major constituent elements of the mantle are Silicon and Magnesium and hence it is also termed as SIMA

20. THE CORE
 Beneath the mantle is the Earth’s core.
• The core-mantle boundary is positioned at the depth of 2,900 km.
• The inner core is in the solid-state whereas the outer core is in the
liquid state.
• The core is made up of very heavy material mostly constituted by
nickel and iron. Hence it is also called the “nife” layer.
 Because the outer core contains iron. When it flows it
generates a magnetic field. This is the source of the Earth’s
magnetic field.
 1/3 of the Earth’s mass
 Very hot

21. Outer core
 The core of the earth is like a ball of very
hot metals.
 The outer core is liquid
 The outer core is made up of iron and is
very dense
 The inner core of the Earth has
temperature and pressure so great that
the metals are squeezed together and are
not able to move.
 The inner core is a solid.
Inner core

22. HYDROSPHERE
 Liquid portion of the earth.
 The Earth is over 70% water!
 The hydrosphere is all the water on, under, or around
Earth
 Water on Earth is found in all the states of matter :
Solid in the form of glaciers and ice caps.
Gas in the form of clouds and water vapor.
Liquid in oceans, rivers and seas.

23. WATER
 One of the most important substances
known to a man without which life would
not be possible.
 Comprises ¾ of the Earth’s surface.
 Approximately 2/3 of the human body
weight.
 Freshwater – 3% (The majority of the world’s
freshwater is locked in the Antartica ice cap)
 Saline water – 97%

25. SOURCES AND REFERENCES
 https://byjus.com/biology/our-environment/
 https://volcano.oregonstate.edu/earths-layers-lesson-1
 https://www.slideshare.net/zeal_eagle/hydrosphere-30396943