THE
BEGINNINGS
OF EARTH
Earth
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Is the third planet from
the sun in the solar
system.
Scientist estimate that
the planet is about 4.5
billion years old.
It started out as an
immensely hot
gaseous mass.
Oblate spheroid
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


Is the third planet from the sun in the solar
system.
Scientist estimate that the planet is about
4.5 billion years old.
It started out as an immensely hot gaseous
mass.
Oblate spheroid
Formative period:
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Was said to be along the path of meteorites,
comets and other planetary bodies.
Some scientist speculate that a large collision with
a foreign body caused its present tilt.
The Primitive volcanoes would continuously and
randomly erupt. At the same time, flying planetary
debris and other masses passed into Earth’s orbit
and crashed on its surface.
Uniqueness
of Earth
There is a life .
Several factors
necessary to support and
sustain life.
Water which in its liquid
form is vital for DNA and
proteins to swim around
and interact with the
environment to carry out
reactions needed for life.
Goldilocks zone- orbits of planets that are neither
too hot nor too cold for life exist.
In case of Earth, its position is exactly on the
habitable zone of the sun. The present location of
Mars (too cold) and Venus (too hot) lie outside this
zone.
MODULE 2:
EARTH’S
STRUCTURE
AND
COMPOSITION
The Systems
of Earth
There are four
subsystems:
Geosphere
Hydrosphere
Atmosphere
Biosphere
Geosphere
 Gaia hypothesis- which states that organisms
interact with their inorganic surroundings and
create a self-regulating, complex system that
helps maintain the condition necessary for life on
the planet.
 Is the solid portion of Earth that includes the
interior structure, rocks and minerals, landforms,
down to the deep depths of the core and the
processes that shape Earth’s surface.
Geologist-scientists that study the part of the Earth.
Lithosphere-which covers only Earth’s crustal part
and upper mantle.
GEOSPHERE’S INTERNAL STRUCTURE
AND SURFACE FEATURES
Earth has
three main
layers:
Crust
Mantle
Core
Modern technology has allowed the
identification of materials in the interior of
Earth through seismic waves.
Two types of waves traveling through Earth:
 p-waves= which travel fast through both
solids and liquids.
 s-waves= which slowly travel only through
solids.
Seismologists and volcanologist study the
components of Earth through seismic waves.
Crust
Mohorovicic discontinuity
 Consists of a 5 to 70 km
thick layer of oceanic and
continental crust overlaying
another thick layer of rocks
and metals.
 Continental crust is thicker
than the oceanic crust.
 It composed of elements
that include oxygen,
silicon, aluminum, iron,
calcium, sodium,
potassium and
magnesium.
 Discovered by Croatian
seismologist Andrija
Mohorovicic in 1909 while
studying the seismic waves
in an earthquake in Croatia.
 Discontinuity- the velocity of
the seismic waves behaved
differently as they traveled
through the layer before the
mantle.
 Moho- the transitional
boundary that divides the
crust and the mantle.
Mantle
 Is made of solid rock.
 Considered the largest part
of Earth and 84% of Earth’s
total volume.
 It lies between the
extremely hot core and the
thin outer layer, the crust.
 Asthenosphere- upper part
of the mantle directly below
the crust.
 The extreme temperature
and pressure in the
asthenosphere causes the
rocks to become ductile
and thus move like liquid.
 Rocks that make up the
mantle are made mostly
of silicate minerals.
 Common silicates found
in the mantle include
pyroxene, olivine, and
garnet.
 Gutenburg
discontinuity
 Name after its German
discoverer.
Beno Gutenburg.
 Transitional boundary
between the mantle and
core.
Core
 Made up of iron (Fe)
and nickel (Ni).
 Iron is important
because it is the
primary source of
Earth’s magnetic
field.
 Without this
magnetic field, solar
winds could destroy
Earth’s atmosphere
and will destroy all
living forms on the
planet.
 Lehmann discontinuity
which was discovered in
1936 by Danish seismologist
Inge Lehmann.
 Lehmann studied the shock
waves and realized that
these waves had traveled
some distance into the core
and then bounced off some
kind of boundary.
 Lehmann believed that there
indeed lies a unique layer
that separates the liquid
outer core from the solid
inner core.
Hydrosphere
 The total amount of
water found on Earth.
 This includes water in
various formswhether in ice, vapor
or liquid.
 It covers 70% of the
entire Earth’s surface
and most of it is
ocean water.
 Associated with the
existence of life.
Hydrological cycle- the
interaction of energy and
matter that prompts the
transformation of water
from one phase to another,
allowing it to circulate and
travels to different regions
on the planet.
Water cycle
 Evaporation-water vapor
rises to the atmosphere
 Condensation Precipitation-Liquid
 Infiltration
Distribution of Water on Earth
All water found on Earth are
natural but all is safe for
drinking.
It divided into two groups
Surface water- found on
Earth’s surface
May either be salt water or
fresh water.
Salt water- have higher
content of salt and larger
bodies such as oceans, seas,
bays and gulfs.
Fresh water-found in lakes,
rivers, streams, springs and
falls.
Ground water-found
below the ground.
The water found beneath
Earth’s surface in the zone
of saturation (where every
pore space between rock
and soil particles is
saturated with water)
Aquifer- a layers of rocks
that carry or hold water.
It may contain large
amounts of minerals such
as magnesium and calcium.
Atmosphere
Composition of
the Atmosphere:
Is composed
78% nitrogen
21% oxygen
1% other gases
such as carbon
dioxide, argon
and water
vapor.
Layers of the
Atmosphere
1. Troposphere
2. Stratosphere
3. Mesosphere
4. Thermosphere
Troposphere
Stratosphere
 Considered to be the
densest among the
layers of the
atmosphere.
 Temperature drops with
altitude.
 Weather variations
occurs.
 Jets and planes would
fly slightly above the
troposphere.
 Tropopause- prior to
reaching the next layer
above the troposphere is
a thin buffer zone.
 Ozone layer-contains a
high concentration of
ozone.
 UV-B = Another type of
radiation
 Hazardous as it
penetrates directly
through the protective
layers of organisms,
damaging DNA
molecules.
 Ozone-depleting
substances (ODS)=
directly destroy the ozone
molecules in the ozone
layer.
Mesosphere
Thermosphere
 Considered to be the
coldest layer because
the heat from the sun is
decreased as absorb
by the thermosphere
which is directly above
it.
 Because of the
absence of radiationabsorbing gases.
 It protects from
planetary debris.
 Mesopause – a thin
buffer zone above the
mesosphere.
 Considered the hottest layer
because it absorbs highly
energetic heat from the sun.
 This extreme heat causes the
atmospheric particles to
become electrically charged
making it possible for radio
waves to bounce off and be
received beyond the horizon.
 Ionosphere- lower part of
thermosphere where most
collisions of oxygen and
nitrogen particles are
electrically charged by the
solar wind.
 Ions- charged particles.
Thermosphere
Solar winds-the ions which
stream continuously from the
sun’s surface.
The energy released during
the collisions causes a
colorful glow around the
poles called auroras.
Aurora borealis –(Northern
lights) regions like the Arctic
and Northern Canada.
Aurora Australis- (Southern
lights) regions like Antarctic
and Southern Australia.
Biosphere
• Is considered an
open system
when it comes to
the transfer of
energy and a
closed system
when it comes to
matter that
makes up all the
living
components of
Earth.
• In this system, an
organism can consume
another organism to allow
energy to transfer to other
orders of consumers in the
ecosystem. Life exist in all
the subsystems of Earth –
on land consumers in the
ecosystem (geosphere), in
water (hydrosphere), and
in the air (atmosphere).
• Biosphere interacts,
exchanges matter and
energy with other system.
Biosphere
Is considered an
open system
when it comes to
the transfer of
energy and a
closed system
when it comes to
matter that
makes up all the
living
components of
Earth.
Biosphere
Is considered an open
system when it comes
to the transfer of energy
and a closed system
when it comes to matter
that makes up all the
living components of
Earth.
12 KM (7 MI)
2
2 STRATOSP
. HERE
49 KM (30 MI)
3 MESOSPH
. ERE
85 KM (53 MI)
4 THERMOSPH
. ERE
700 KM (435 MI)
5 EXOSPHERE
.
700+ KM (500+
MI)
3
1
4
5