Earth’s Resources, Earth’s Resources, Interactions, and CyclesInteractions, and Cycles

The Earth has renewable, nonrenewable, and inexhaustible resources.

Past events have led to the formation of many of the Earth’s resources.

The Earth’s different systems interact with each other. Earth’s water, carbon and nitrogen are continually

recycled. Because of its atmosphere, soil, oceans, and living

things, Earth’s physical characteristics are different from those of the moon.

Types of Natural ResourcesTypes of Natural Resources

A natural resource is something found in nature that people are able to use to meet their needs.

There are three types:– Renewable Resources– Nonrenewable Resources– Inexhaustible Resources

Renewable ResourcesRenewable Resources

A renewable resource is something that can be replaced.

A renewable resource can be replaced by natural processed such as growth.

Renewable resources must be given time to renew itself.

Examples are forests, livestock, and food crops.

Nonrenewable ResourcesNonrenewable Resources

A nonrenewable resource is formed over a very long period of time and cannot be replaced or renewed.

Examples are oil, coal, copper, and other minerals.

Once used, the nonrenewable resources cannot be replaced.

Inexhaustible ResourcesInexhaustible Resources

An inexhaustible resource is in such a large supply that it cannot be used up by human activity.

Examples are energy from the sun, wind power, and heat from deep inside the Earth.

SoilSoil

Some soils can grow different crops better than others.

Because of this, each type of soil is a renewable resource.

To prevent erosion of the soil, farmers must practice soil conservation.

Examples of soil conservation—planting crops that hold the soil together, strip cropping, contour plowing, and terracing.

GasesGases Since most of the atmosphere is made of nitrogen, this gas

is almost inexhaustible. As air pollution increases, the nitrogen becomes unusable. Oxygen is a renewable resource. Plants produce oxygen

during photosynthesis If we reduce plant life by cutting down rainforests, we may

reduce our oxygen. The breathing of animals and the burning of materials

create a gas called carbon dioxide. Some scientists believe the large amount of of carbon

dioxide now being produced has caused a heating up of Earth’s surface, known as global warming.

WaterWater

Water is needed by all living things to survive.

Fresh water is a valuable renewable resource. It is constantly replaced by the water cycle.

Water pollution threatens this water.

RocksRocksRocks above and below the Earth's surface

contain many valuable minerals and other resources.

Because there is a great deal of sandstone and silicon, they might be considered inexhaustible.

However, because rocks and minerals cannot be replaced after they are taken from the ground, they are considered nonrenewable resources.

Fossil FuelsFossil Fuels

Fossil fuels are burned to release large amounts of energy.

Coal is a brown or black rock formed from plants in forests or swamps 400 million years ago. When burned, coal releases the energy stored by plants from the sum millions of years ago.

Oil and natural gas were formed by very tiny one-celled plants and animals in the ocean.Over millions of years, heat and pressure changed their soft bodies to liquid oil and natural gas.

Fossil Fuels ContinuedFossil Fuels Continued

It takes millions of year for fossil fuels like oil and gas to form.

They can only be burned once.Form this reason, they are important

nonrenewable resources.Some scientists fear their supply on Earth is

being used at a faster rate than new energy resources can be found.

Interactions of Oceans and Interactions of Oceans and Land FormsLand Forms

Rivers carry sediment from the land into the river. Ocean currents take some of this sediment,

accumulated over millions of years, to coastlines where it forms sandy beaches.

Tides come in twice each day as sea levels rise and fall.

Tides and waves erode the coastlines, wearing away rock and dissolving minerals.

Weather PatternsWeather Patterns Weather refers to conditions in the atmosphere at

Earth’s surface—including temperature, rainfall or snowfall, and wind.

Climate is the typical weather of a place over a long period of time.

Weather results form the interaction of several systems—land features, energy from the sun heating the Earth’s atmosphere, and the Earth’s oceans.

The temperature stays cooler over lakes and oceans in the summer and warmer in the winter. This affects air flowing over these areas.

Rainfall PatternsRainfall Patterns

Because air cools as it rises over a mountain, the ocean side of a mountain often has heavy rainfall.

The air loses its moisture and becomes drier by the time it reaches the other side of the mountain, which has less rain.

Winds and TornadosWinds and Tornados

The uneven heating of the atmosphere by the sun create typical wind patterns.

Cold air sinks and warm air rises.Tornadoes are high-speed winds that whirl

in a funnel.A tornado occurs when dry, cool air meets

warm, humid air.

Tropical HurricanesTropical Hurricanes

Hurricanes occur in tropical regions in late summer and early fall when the ocean water is very warm.

The warm ocean water evaporates quickly and rises.

Air around the rising air column begins to spin at high speeds.

The hot air rises until it cools. Then it releases energy and causes heavy rains,

winds, and lightning.

The Earth’s CyclesThe Earth’s Cycles

Cycles are processes that go through a series of steps in which the lat step leads back to the first step. Then the process begins all over again.

Important Cycles on Earth– The Water Cycle– The Carbon Cycle– The Nitrogen Cycle

The Water CycleThe Water Cycle

The water cycle is the process by which the Earth’s water moves into and out of the atmosphere.

Steps in the water cycle– Evaporation– Condensation– Precipitation– Excess precipitation runs off into rivers, lakes and

streams or is absorbed by the ground and becomes groundwater. Then some evaporates and the cycle begins again.

The Carbon CycleThe Carbon Cycle Carbon is continuously recycled among the

atmosphere (as carbon dioxide), plants, and animals.

Steps in the carbon cycle– Algae and plants convert carbon dioxide from the

air into sugars during photosynthesis.– Animals eat the stored carbon in the algae and

plants; these animals return carbon dioxide to the air by breathing and during decay of their bodies and waste.

– The remains of some plants and animals become part of the Earth’s crust by turning into coal, oil, or limestone.

– Fossil fuels return carbon dioxide to the air when they are burned.

The Nitrogen CycleThe Nitrogen Cycle

Although nitrogen is plentiful in the air, it is not in a form plants and animals can use.

Small organisms called bacteria turn the nitrogen into useful nitrates.

Look at the chart of the nitrogen cycle on page 168

The Nitrogen Cycle StepsThe Nitrogen Cycle Steps Waste products and remains of dead animals and plants are

broken down by bacteria, leaving nitrates in the soil.– Some bacteria convert nitrogen compounds into nitrogen gas,

which enters the atmosphere.– Plants obtain nutrients from the soil

Animals eat plants or other animals with nitrogen compounds.

Certain types of bacteria and algae convert nitrogen gas from the atmosphere into nitrogen compounds.

Animals eat these bacteria and algae, and convert their nitrates into their own nitrogen-based compounds

Animals eat plants or other animals with nitrogen compounds.

Human ActivitiesHuman Activities

Problems can arise when human activities interfere with the water, carbon, and nitrogen cycles.

By burning fossil fuels, humans release more carbon dioxide than plants can use.

With the reduction of rainforests, the number of plants conducting photosynthesis is reduced.

When these things occur, the carbon cycle is changed and greater amounts of carbon dioxide build up in the atmosphere.

Comparing the Earth and Comparing the Earth and MoonMoon

The moon is a rocky sphere without water or air. The Earth is made of rocky material that is mostly

covered with water. Earth has an atmosphere. Because the moon has no atmosphere, its surface is

marked by craters from meteors. Temperatures on Earth do not vary as greatly as they

do on the moon, because our atmosphere holds in the heat and reduces the extremes in temperature.

Our atmosphere also traps water vapor and sends it back to Earth as rain or snow.