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.