Transcript Earth`s Resources, Interactions, and Cycles

Earth’s Resources,
Interactions, and Cycles
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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 Resources
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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 Resources
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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 Resources
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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 Resources
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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.
Soil
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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.
Gases
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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.
Water
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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.
Rocks
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Rocks 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 Fuels
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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 onecelled 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 Continued
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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
Land Forms
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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 Patterns
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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 Patterns
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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 Tornados
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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 Hurricanes
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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 Cycles
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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 Cycle
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The water cycle is the process by which the
Earth’s water moves into and out of the
atmosphere.
 Steps in the water cycle
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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 Cycle
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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 Cycle
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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 Steps
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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
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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 Activities
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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
Moon
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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.