Cycles in Nature

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Chapter 19
Cycles in Nature
Preview
Section 1 The Cycles of Matter Section 2
Ecological Succession
Concept Mapping
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Section 1 The Cycles of Matter
Chapter 19
Bellringer
What are the three different physical states of
water that are found on Earth? Name one way that
you use water in each of these states in your
daily life. Write your answers in your science
journal.
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Section 1 The Cycles of Matter
Chapter 19
Objectives

• Diagram the water cycle, and explain its
  importance to living things.
• Diagram the carbon cycle, and explain its
  importance to living things.
• Diagram the nitrogen cycle, and explain its
  importance to living things.

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Section 1 The Cycles of Matter
Chapter 19
The Water Cycle

• The movement of water between the oceans,
  atmosphere, land, and living things is known as
  the water cycle.
• How Water Moves During evaporation, the suns
  heat causes water to change from liquid to vapor.
• In the process of condensation, the water vapor
  cools and returns to a liquid state.

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Section 1 The Cycles of Matter
Chapter 19
The Water Cycle, continued

• The water that falls from the atmosphere to the
  land and oceans is called precipitation. Rain,
  snow, sleet, and hail are all forms of
  precipitation.
• Most precipitation falls into the ocean.
• The precipitation that falls on the land and
  flows into streams, rivers, and lakes is called
  runoff.
• Groundwater is precipitation that seeps into the
  ground and is stored between or within rocks.
  Groundwater slowly flows back into the soil,
  streams, rivers, and oceans.

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Section 1 The Cycles of Matter
Chapter 19
The Water Cycle
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Section 1 The Cycles of Matter
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The Water Cycle, continued

• Water and Life Without water, there would be no
  life on Earth. All organisms, from bacteria to
  animals and plants, are composed mostly of water.
• Water helps transport nutrients and waste within
  an organism.
• Water helps regulate temperature.
• All water taken in by an organism is eventually
  returned to the environment.

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Section 1 The Cycles of Matter
Chapter 19
The Carbon Cycle

• Besides water, the most common molecules in
  living things are organic molecules, or molecules
  that contain carbon.
• The exchange of carbon between the environment
  and living things is known as the carbon cycle.

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Section 1 The Cycles of Matter
Chapter 19
The Carbon Cycle, continued

• Photosynthesis and Respiration During
  photosynthesis, plants use carbon dioxide from
  air to make sugars.
• Most animals get the carbon and energy they need
  by eating plants. Plants and animals break down
  sugar molecules to release energy in a process
  called respiration.
• Respiration uses oxygen and releases carbon
  dioxide and water back into the environment.

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Section 1 The Cycles of Matter
Chapter 19
The Carbon Cycle, continued

• Decomposition and Combustions The breakdown of
  substances into simpler molecules is called
  decomposition.
• For example, when fungi and bacteria decompose
  organic matter, carbon dioxide and water are
  returned to the environment.
• Combustion is the process of burning a substance,
  such as wood or fossil fuels. Combustion of
  organic matter releases carbon.

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Section 1 The Cycles of Matter
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The Carbon Cycle
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Section 1 The Cycles of Matter
Chapter 19
The Nitrogen Cycle

• Living things need nitrogen to build proteins and
  DNA.
• The movement of nitrogen between the environment
  and living things is called the nitrogen cycle.

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Section 1 The Cycles of Matter
Chapter 19
The Nitrogen Cycle, continued

• Converting Nitrogen Gas Although about 78 of the
  Earths atmosphere is nitrogen gas. Most
  organisms cannot use nitrogen gas directly.
• Bacteria in the soil are able to change nitrogen
  gas into forms that plants can use. This process
  is called nitrogen fixation.
• Other organisms get the nitrogen they need by
  eating plants or animals that eat plants.

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Section 1 The Cycles of Matter
Chapter 19
The Nitrogen Cycle, continued

• Passing It On On When organisms die, decomposers
  break down the remains.
• Decomposition releases a form of nitrogen into
  the soil that plants can use.
• Certain types of bacteria in the soil convert
  nitrogen to a gas, which is returned to the
  atmosphere.

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Section 1 The Cycles of Matter
Chapter 19
The Nitrogen Cycle
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Section 1 The Cycles of Matter
Chapter 19
Many Cycles

• Other forms of matter on Earth also pass through
  cycles. Many of the minerals that living cells
  need, such as calcium and phosphorous, are cycled
  through the environment.
• Each of the cycles is connected in many ways.
• Living organisms play a part in each of the
  cycles.

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Section 2 Ecological Succession
Chapter 19
Bellringer

• Imagine that you have been hired to oversee the
  maintenance of a public forest. Answer the
  following questions to describe how you would
  approach the task
• How would you evaluate the health of the forest?
• What actions would you take to keep the forest
  healthy?
•  
• Record your answer in your science journal.

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Section 2 Ecological Succession
Chapter 19
Objectives

• Describe the process of succession.
• Contrast primary and secondary succession.
• Explain how mature communities develop.

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Section 2 Ecological Succession
Chapter 19
Regrowth of a Forest

• Succession The replacement of one type of
  community by another at a single place over a
  period of time is called succession.
• The regrowth of a forest after a forest fire is
  an example of succession.
• Succession takes place in all communities, not
  just those affected by disturbances such as
  forest fires.

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Section 2 Ecological Succession
Chapter 19
Primary Succession

• Sometimes, a small community starts to grow in an
  area where other organisms had not previously
  lived.
• Over a very long time, a series of organisms live
  and die on the rock. The rock is slowly
  transformed into soil. This process is called
  primary succession.

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Section 2 Ecological Succession
Chapter 19
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Section 2 Ecological Succession
Chapter 19
Secondary Succession

• Sometimes, a community is disturbed in some way.
  If soil is left intact, the original community
  may regrow through a series of stages called
  secondary succession.

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Section 2 Ecological Succession
Chapter 19
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Section 2 Ecological Succession
Chapter 19
Ecological Succession
Click below to watch the Visual Concept.
Visual Concept
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Section 2 Ecological Succession
Chapter 19
Mature Communities and Biodiversity

• In the early stages of succession, only a few
  species grow in an area. As a community matures,
  it may be dominated by a well-adapted,
  slow-growing climax species.
• The variety of species that are present in an
  area is referred to as biodiversity. Having
  biodiversity helps communities lessen the impact
  and spread of disturbances such as insect
  invasions.

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Section 2 Ecological Succession
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Mature Communities and Biodiversity, continued

• Mature communities tend to have biodiversity. A
  mature community simply has organisms that are
  well adapted to live together in the same area
  over time.

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Cycles in Nature
Chapter 19
Concept Mapping
Use the terms below to complete the Concept
Mapping on the next slide.
water cycle decomposition carbon cycle photosynthesis carbon combustion condensation precipitation

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Cycles in Nature
Chapter 19
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Cycles in Nature
Chapter 19