EARTH AND LIFE: Quarter 1- Week 1 (A): THE UNIQUENESS OF EARTH

[Musika]

Good day everyone. Welcome to Teacher

Julie Channel.

[Musika]

Hello everyone. We have our new lesson

in Earth and life science which is all

about the uniqueness of Earth. This will

be the first quarter topic and week one.

This topic is milkbased.

For the most essential learning

competencies after going through this

lesson, you are expected to first is to

recognize the uniqueness of Earth being

the only planet in the solar system with

properties necessary to support life.

The second one is to explain that the

earth consist of four subsystems

across whose boundaries matter and

energy flow.

What makes the Earth a unique planet?

Earth is a unique planet. It is the only

planet capable of sustaining life

because of the right combination of

elements, molecules, and ions that react

under the right physical conditions to

make up the processes supportive to

life.

It has an atmosphere that serves as a

thermostat that is necessary to regulate

its surface temperature. It is also

contains the right amount of liquid

water and oxygen that serves as

essential compounds needed in biological

processes such as cellular respiration

and photosynthesis.

In the Milkyway galaxy alone, there are

about 1 billion planets. However, only

the Earth is habitable. Other planets

may be too hot or too cold. They may

also be too big or too small. Other

planets may not have an atmosphere or a

magnetic field or may not be in an orbit

at all. Fortunately, planet Earth

possesses all the features and

characteristics that make it habitable

for all living forms.

Let us go through with each one of the

Earth's characteristics.

The first one is the Earth's location.

Earth is the third planet in the solar

system. It is one of the inner planets

next to Venus. Its distance from the sun

is about 93 million mil and it takes

about 500 seconds for sunlight to reach

the earth surface. This distance from

the sun is enough to support life. The

distance between the earth and the sun

is strategic enough to put this

essential chemical equation to work. If

the earth had been too close to the sun,

its surface would have been dry and

lifeless just like Mercury and Venus. If

it had been too far like Uranus and

Niptune, it would have been cold and

dark. Earth's tactical location also

prevents it from planetary collisions.

The fact that Jupiter is the biggest

planet in the solar system puts planet

Earth at an advantage as far as life is

taken into consideration.

Between Mars and Jupiter are asteroid

belts. Since Jupiter is so massive, its

gravity is so strong that it pulls

asteroids and other space debres towards

itself, warding it away from the earth.

The second earth's characteristics is

the earth's atmosphere. The atmosphere

is the gasous layer that envelop the

earth. It regulates the planet's surface

temperature. Most of the element that

make up the atmosphere is nitrogen and

it consists about 78%.

If we compare the earth to an apple, the

atmosphere is relatively the size of its

peel. However, due to its cooling

mechanisms, it protects the living

things to the uh directly affected by

harmful radiation.

Photissociation is the process by which

the ozone molecules in the atmosphere

break down into decomposition reaction

into elemental oxygen and diatomic

oxygen.

The ozone absorb high energy solar

radiation and then converts it into low

energy radiation. This way harmful high

energy radiation will not go directly

into the earth surface.

Another characteristics of Earth is the

Earth's size and mass. The size of the

Earth also play a vital role in keeping

its life support system afloat. The size

of the planet is directly related to its

gravitational pool. The acceleration due

to gravity helps the planet maintains it

atmosphere.

If the earth had been bigger than it is,

its gravity would have been stronger to

the point of not keeping an atmosphere

around it. If it had been too small, on

the other hand, it would not had been

able to sustain a gasous layer since its

gravity is too weak. Earth interact

gravitationally with the sun. Its

gravity because of its mass also keeps

the moon along its orbit. The moon is

the only natural satellite of the earth

plays a vital rule in the existence of

all life forms.

Another earth's characteristics is the

earth's magnetic field. Our planet is

like a big ball magnet. Its geographic

north serves as its magnetic south and

its geographic south serve as its

magnetic north. The region around the

earth that is dominated by the magnetic

field is called the magnetosphere

which extends about 65 km in space. Its

magnetic properties are the result of

its internal activities involving

electrical current flowing in the molt

core made possible by its rotation. The

inner core is the solid layer of the

earth and is made predominantly of iron.

Since it is compressed by pressure due

to earth's gravity, it is a solid in

form and the outer core on the other

hand is a liquid in form and it's made

up predominantly of iron and nickel.

As the earth spins, the flow of liquid

iron and nickel in the outer core

produces an electrical current

producing a magnetic field. The

invisible magnetic field then passes

through the earth's layer and in the

space. This magnetic field shelds earth

from the harmful surge of charged

particles from the sun called the solar

winds and the other space weather. Most

of the particles of solar winds cannot

cross the earth because it gets

deflected by the magnetic field. Without

the magnetic field, the earth would have

been as hot and lifeless as Mars.

Another characteristics of Earth is the

presence of water. Life, as we know, it

is impassible without biologically

essential compound called the water. 3/4

or 71% of the earth surface is covered

with water. The scientists have found

out that there are other planets of the

universe that contain water. However,

this compound may exist as an ice or

water vapor alone.

On the earth. However, water exist as

gas forming clouds, as a liquid in the

form of oceans and lakes, and as a solid

in the form of ice caps. This is due to

the hydrologic cycle. Earth has the

right amount of water to keep its

habitability.

Water has a calling effect due to its

heat capacity. It has the

characteristics to absorb heat without

raising its temperature. As a result,

life on earth will be benefited from the

cooling effect of water.