The Earth's System

WHY DOES IT MATTER?

















Earth’s supply of matter is finite and cycles continuously among Earth’s four major reservoir systems. Energy, on the other hand, must be supplied constantly to maintain this cycling and support life processes.

CHAPTER OUTLINE:
Earth: A Unique Planet Earth
Basics Earth’s
Earth's Interior
Earth as a Magnet
Earth’s Gravity

Energy in the Earth System
Earth-System Science
Earth’s Four Spheres
Earth’s Energy Budget
Cycles in the Earth System

Ecology
Ecosystems
Balancing Forces in Ecosystems
Energy Transfer
Human Stewardship of the Environment

Energy in the Earth System

Why it Matters?????

Viewing Earth as a system helps scientists study ways that matter and energy interact to create and support Earth’s life forms and living conditions.

Direct observation of Earth’s interior has been limited to the upper few kilometers that can be reached by drilling. So, scientists rely on indirect methods to study Earth at greater depths. For example, scientists have made important discoveries about Earth’s interior through studies of seismic waves. Seismic waves are vibrations that travel through Earth. Earthquakes and explosions near Earth’s surface produce seismic waves. By studying these waves as they travel through Earth, scientists have determined that Earth is made up of three major compositional zones and five major structural zones.

​Earth’s Interior

Compositional Zones of Earth’s Interior

The thin, solid, outermost zone of Earth is called the crust. The crust makes up only 1% of Earth’s mass.

The mantle, the layer that underlies the crust, is denser than the crust. The mantle is nearly 2,900 km thick and makes up almost two-thirds of Earth’s mass.

The center of Earth is a sphere whose radius is about 3,500 km. Scientists think that this center sphere, called the core, is composed mainly of iron and nickel.

Structural Zones of Earth’s Interior

The three compositional zones of Earth’s interior are divided into five structural zones. The uppermost part of the mantle is cool and brittle. This part of the mantle and the crust above it make up the lithosphere, lithosphere, a rigid layer 15 to 300 km thick. Below the lithosphere is a less rigid layer, known as the asthenosphere. Below the asthenosphere is a layer of solid mantle rock called the mesosphere.

Earth’s Four Spheres

Matter on Earth is in solid, liquid, and gaseous states. The Earth system is composed of four “spheres” that are storehouses of all of the planet’s matter.

The Atmosphere The blanket of gases that surrounds Earth’s surface is called the atmosphere. atmosphere. The atmosphere provides the air that you breathe and shields Earth from the sun’s harmful radiation.

The Hydrosphere Water covers much of Earth’s surface, and 97% of this water is contained in the salty oceans. The remaining 3% is fresh water. All of Earth’s water makes up the hydrosphere.

The Geosphere The mostly solid part of Earth is known as the geosphere. This sphere includes all of the rock and soil on the surface of the continents and on the ocean floor.

The Biosphere Another one of the four subdivisions of the Earth system is the biosphere. The biosphere biosphere is composed of all of the forms of life in the geosphere, in the hydrosphere, and in the atmosphere.

Ecology

Ecology is the study of the complex relationships between living things and their nonliving, or abiotic, environment. Some ecologists also investigate how communities of organisms change over time.