Chapter 1 Section 1
Planet of Life
• Earth is one of the nine planets in the solar
system.
• Earth is the third planet from the sun.
• Mercury, Venus, Earth and Mars are known
as the inner planets and are made mostly of
rock.
• The other five planets are the outer planets
and are made of mostly gases, with the
exception of Pluto, which is rocky like the
inner planets.
• Earth is the only planet to support life or
living things called organisms.
• The lithosphere is the layer of land that
forms Earth’s surface and includes rocks,
soil, and sand.
• The hydrosphere includes all the parts of the
Earth that are made up of water and
includes oceans, lakes, rivers and
underground water and clouds in the air.
• The atmosphere is the layer of air that
surrounds Earth.
• One of the most important reasons Earth
can support life is the presence of liquid
water.
• Although water exists elsewhere in the solar
system, it is usually in the form of ice or
vapor.
• On Earth, liquid water in the hydrosphere
stores heat.
• Water absorbs heat during warm periods
and releases it during cold periods.
• Another reason Earth is able to support life
is its atmosphere.
• Air is a mixture of gases, including
nitrogen, oxygen, carbon dioxide, and water
vapor.
• Most organisms require oxygen to use
energy.
• Plants require carbon dioxide to help
capture and store energy from the sun.
• Almost all energy used by organisms comes
from the sun and travels in the form of
waves.
• Each type of wave has a different range of
wavelengths.
• Most waves are invisible.
• Waves in narrow range of wavelengths,
called the visible spectrum, can be seen by
the human eye.
• Interactions among living and nonliving
parts of the Earth are the subject of ecology.
• Ecology is the study of Earth, the home of
living organisms.