LESSON
3
Content Standard
The learners shall be able to understand the subsystems
(geosphere, hydrosphere, atmosphere, and biosphere) that make up the
Earth.
Learning Competencies
The learners shall be able to
1.
recognize the uniqueness of Earth,
being the only planet in the solar system with properties necessary to support life (S11/12ES-Ia-e-3).
2.
explain that the Earth consists of
four subsystems, across whose boundaries matter and energy flow (S11/12ES-Ia-e-4)
3.
show the contributions of
personalities/people on the understanding of Earth Systems (S11/12ES-Ia-e-6).
3.
Specific Learning Outcomes
At the end of this lesson, the learners will be able to:
1.
Recognize the difference in the
physical and chemical properties between the Earth and its neighboring planes;
and
2.
Identify the factors that allow a
planet to support life.
3.
Define the concept of a system;
4.
Recognize the Earth as a system
composed of subsystems; and
5.
Discuss the historical development of
the concept of Earth System.
Life of
Earth
Earth is the only habitable planet in our
solar system due to the following:
1. Existence
of Liquid wate
a.
may
originate from volcanism or from icy meteors from space;
b.
water
exists in three (3) phases on earth – liquid, solid (ice) and gas (water vapor)
2. Atmosphere
a.
Gravity is
responsible for having atmosphere
b.
Traps
certain amount of heat from the sun to warm the earth (greenhouse effect)
c.
Protects
the earth from too much radiation from the sun
3. Heat
Source
a.
Radiogenic
heat – comes from the earth’s core – a thermonuclear reactor
b.
Sunlight –
another source of heath from the sun
Goldilocks
Zone
The habitable zone is the belt around a star
where temperatures are ideal for liquid water -- an essential ingredient for
life as we know it -- to pool on a planet's surface. Earth lies within the
habitable zone of our star, the sun. Beyond this zone, a planet would probably
be too cold and frozen for life (though it's possible life could be buried
underneath a moon's surface). A planet lying between a star and the habitable
zone would likely be too hot and steamy.
NASA's Kepler mission is helping scientists in
the quest to find these worlds, sometimes called Goldilocks planets after the
fairy tale because they orbit where conditions are "just right" for
life. Kepler and other telescopes have confirmed a handful so far, all of which
are a bit larger than Earth -- the Super Earths. The search for Earth's twin, a
habitable-zone planet as small as Earth, is ongoing.
Earth
Subsystems
1.
Definition
of a System - A set of interconnected
components that are interacting to form a unified whole.
2.
Components
or subsystems of the Earth System.
3.
Earth
system is essentially a closed system.
It receives energy from the sun and
returns some of this energy to space.
1.
Atmosphere.
A.
The
atmosphere is the thin gaseous layer that envelopes the lithosphere.
B.
The
present atmosphere is composed of 78% nitrogen (N), 21% oxygen (O2), 0.9%
argon, and trace amount of other gases.
C.
One of the
most important processes by which the heat on the Earth's surface is redistributed is through atmospheric
circulation.
D.
There is
also a constant exchange of heat and moisture between the atmosphere and the
hydrosphere through the hydrologic cycle.
2. Geosphere (Lithosphere).
A.
The geosphere or lithosphere includes the rocks of
the crust and mantle, the metallic liquid outer core, and the solid metallic
inner core.
B.
Plate
Tectonics - an
important process shaping the surface of the Earth. The primary driving mechanism is the Earth's
internal heat, such as that in mantle convection.
3.
Biosphere.
A.
The
biosphere is the set of all life forms on Earth.
B.
It covers
all ecosystems—from the soil to the rainforest, from mangroves to coral
reefs,
and from the plankton-rich ocean surface to the deep sea.
C.
For the
majority of life on Earth, the base of the food chain comprises
photosynthetic organisms.
D.
During
photosynthesis, CO2 is sequestered from
the atmosphere, while oxygen is released
as a byproduct. The biosphere is a CO2 sink, and therefore, an important part
of the carbon cycle.
4.
Hydrosphere.
A.
About 70%
of the Earth is covered with liquid water (hydrosphere) and much of it is in
the form of ocean water (Figure 3).
B.
Only 3% of
Earth's water is fresh: two-thirds are in the form of ice (cryosphere), and the remaining
C.
one-third
is present in streams, lakes, and groundwater.
D.
The oceans
are important sinks for CO2 through direct exchange with the atmosphere and
E.
indirectly
through the weathering of rocks.
F.
Heat is
absorbed and redistributed on the surface of the Earth through ocean circulation.
5. The origin
of the systems approach to the study of
the Earth
A.
One of the
first scientist to push for a more integrated or holistic approach in the
understanding of the universe (and by extension the Earth) was Friedrich Wilhelm Heinrich Alexander
von Humboldt. He considered the universe
as one interacting entity.
B.
The term
"biosphere" was
popularized by Vladimir Vernadsky
(1863-1945), a Russian - Ukranian scientist who hypothesized that life is a
geological force that shapes the Earth.
C.
In the
1970s, the Gaia Hypothesis was
jointly developed by James Lovelock,
an English scientist/naturalist, and Lynn
Margulis, an American microbiologist.
According to the Gaia Hypothesis.
the biosphere is a self-regulating system that is capable of controlling
its physical and chemical environment.
D.
In 1983,
NASA advisory council established the Earth
Systems Science Committee. The
committee, chaired by Moustafa Chahine,
published a ground breaking report Earth System Science: A Program For Global
Change in 1988. For the first time,
scientist were able to demonstrate how the many systems interact.
Alternative Learning Resources
Watch the following Youtube videos:
DOWNLOAD THE PDF VERSION HERE.
thank u very much.
ReplyDeletethank u very much.
ReplyDelete