Table of Contents

1
Table of Contents
Introduction to Ecology
Chapter 18

• Section 1 Introduction to Ecology
• Section 2 Ecology of Organisms
• Section 3 Energy Transfer
• Section 4 Ecosystem Recycling

2
Standards
Introduction to Ecology
Chapter 18

• SPI 3210.2.1 Predict how population changes of
  organisms at different trophic levels affect an
  ecosystem.
• SPI 3210.2.2 Interpret the relationship between
  environmental factors and fluctuations in
  population size.
• SPI 3210.2.3 Determine how the carrying capacity
  of an ecosystem is affected by interactions among
  organisms.
• SPI 3210.2.5 Make inferences about how a specific
  environmental change can affect the amount of
  biodiversity.

3
Objectives
Section 1 Introduction to Ecology
Chapter 18

• Identify a key theme in ecology.
• Describe an example showing the effects of
  interdependence upon organisms in their
  environment.
• Identify the importance of models to ecology.
• State the five different levels of organization
  at which ecology can be studied.

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Interdependence A Key Theme in Ecology
Section 1 Introduction to Ecology
Chapter 18

• Organisms and Their Environments
• Species interact with both other species and
  their nonliving environment.
• Interdependence is a theme in ecologyone change
  can affect all species in an ecosystem.

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Ecological Models
Section 1 Introduction to Ecology
Chapter 18

• Ecological models help to explain the environment.

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Making an Ecosystem Model
Section 1 Introduction to Ecology
Chapter 18
7
Levels of Organization
Section 1 Introduction to Ecology
Chapter 18

• Ecologists recognize a hierarchy of organization
  in the environment biosphere, ecosystem,
  community, population, and organism.

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Levels of Organization
Section 1 Introduction to Ecology
Chapter 18
9
Levels of Organization, continued
Section 1 Introduction to Ecology
Chapter 18

• The Biosphere
• The broadest, most inclusive level of
  organization is the biosphere, the volume of
  Earth and its atmosphere that supports life.

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Levels of Organization, continued
Section 1 Introduction to Ecology
Chapter 18

• Ecosystems
• The biosphere is composed of smaller units called
  ecosystems.
• An ecosystem includes all of the organisms and
  the nonliving environment found in a particular
  place.

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Levels of Organization, continued
Section 1 Introduction to Ecology
Chapter 18

• Communities, Populations, and Organisms
• A community is all the interacting organisms
  living in an area.
• Below the community level of organization is the
  population level, where the focus is on the
  individual organisms of a single species.

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Objectives
Section 2 Ecology of Organisms
Chapter 18

• Compare abiotic factors with biotic factors, and
  list two examples of each.
• Describe two mechanisms that allow organisms to
  survive in a changing environment.
• Explain the concept of the niche.

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Ecosystem Components
Section 2 Ecology of Organisms
Chapter 18

• Biotic and Abiotic Factors
• Both biotic, or living, factors and abiotic, or
  nonliving, factors influence organisms. Examples
  of abiotic factors are climate, sunlight, and pH.

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Organisms in a Changing Environment
Section 2 Ecology of Organisms
Chapter 18

• Acclimation
• Some organisms can adjust their tolerance to
  abiotic factors through the process of
  acclimation.

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Organisms in a Changing Environment, continued
Section 2 Ecology of Organisms
Chapter 18

• Control of Internal Conditions
• Conformers are organisms that do not regulate
  their internal conditions they change as their
  external environment changes.
• Regulators use energy to control some of their
  internal conditions.

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Organisms in a Changing Environment, continued
Section 2 Ecology of Organisms
Chapter 18

• Escape from Unsuitable Conditions
• Some species survive unfavorable environmental
  conditions by becoming dormant or by migrating.

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The Niche
Section 2 Ecology of Organisms
Chapter 18

• A niche is a way of life, or a role in an
  ecosystem.

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Objectives
Section 3 Energy Transfer
Chapter 18

• Summarize the role of producers in an ecosystem.
• Identify several kinds of consumers in an
  ecosystem.
• Explain the important role of decomposers in an
  ecosystem.
• Compare the concept of a food chain with that of
  a food web.
• Explain why ecosystems usually contain only a few
  trophic levels.

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Producers
Section 3 Energy Transfer
Chapter 18

• Most producers are photosynthetic and make
  carbohydrates by using energy from the sun.

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Producers, continued
Section 3 Energy Transfer
Chapter 18

• Measuring Productivity
• Gross primary productivity is the rate at which
  producers in an ecosystem capture the energy of
  sunlight by producing organic compounds.
• The rate at which biomass accumulates is called
  net primary productivity.

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Consumers
Section 3 Energy Transfer
Chapter 18

• Consumers obtain energy by eating other organisms
  and include herbivores, omnivores, carnivores,
  detritivores, and decomposers.

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Energy Flow
Section 3 Energy Transfer
Chapter 18

• Food Chains and Food Webs
• A single pathway of energy transfer is a food
  chain.
• A network showing all paths of energy transfer is
  a food web.

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Food Chain in an Antarctic Ecosystem
Section 3 Energy Transfer
Chapter 18
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Food Web in an Antarctic Ecosystem
Section 3 Energy Transfer
Chapter 18
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Energy Flow, continued
Section 3 Energy Transfer
Chapter 18

• Energy Transfer
• Ecosystems contain only a few trophic levels
  because there is a low rate of energy transfer
  between each level.

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Energy Transfer Through Trophic Levels
Section 3 Energy Transfer
Chapter 18
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Objectives
Section 4 Ecosystem Recycling
Chapter 18

• List four major biogeochemical cycles.
• Summarize three important processes in the water
  cycle.
• Outline the major steps in the carbon cycle.
• Describe the role of decomposers in the nitrogen
  cycle.
• Summarize the major steps of the phosphorus cycle.

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The Water Cycle
Section 4 Ecosystem Recycling
Chapter 18

• Key processes in the water cycle are evaporation,
  transpiration, and precipitation.

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Water Cycle
Section 4 Ecosystem Recycling
Chapter 18
30
The Carbon Cycle
Section 4 Ecosystem Recycling
Chapter 18

• Photosynthesis and cellular respiration are the
  two main steps in the carbon cycle.

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Carbon Cycle
Section 4 Ecosystem Recycling
Chapter 18
32
Nitrogen Cycle
Section 4 Ecosystem Recycling
Chapter 18

• Nitrogen-fixing bacteria are important in the
  nitrogen cycle because they change nitrogen gas
  into a usable form of nitrogen for plants.

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Nitrogen Cycle
Section 4 Ecosystem Recycling
Chapter 18
34
Phosphorus Cycle
Section 4 Ecosystem Recycling
Chapter 18

• In the phosphorus cycle, phosphorus moves from
  phosphate deposited in rock, to the soil, to
  living organisms, and finally to the ocean.