Environmental Science: Toward a Sustainable Future Richard T. Wright

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Environmental Science Toward a Sustainable
Future Richard T. Wright
Chapter 2

• Ecosystems What They Are
• PPT by Clark E. Adams

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The Organization of Ecosystems

• A description of ecosystems
• The structure of ecosystems
• The relationship between ecosystems and biomes
• Human impacts on ecosystem structure

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Ecosystem Types in the United States

• Coasts and oceans
• Farmlands
• Forests
• Fresh waters
• Grasslands and shrub lands
• Urban and suburban areas

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Ecosystems A Description

• Biotic communities grouping or assemblage of
  plants, animals, and microbes
• Species different kinds of plants, animals, and
  microbes in the community
• Populations number of individuals that make up
  the interbreeding, reproducing group
• Associations how a biotic community fits into
  the landscape

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How Ecosystems Are Formed
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Ecosystems

• A grouping of plants, animals, and microbes
  occupying an explicit unit of space and
  interacting with each other and their environment

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Ecotone transitional region between different
ecosystems

• Shares many of the species and characteristics of
  both ecosystems
• May also include unique conditions that support
  distinctive plant and animal species

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Ecotone transitional region between different
ecosystems

• Shares many of the species and characteristics of
  both ecosystems
• May also include unique conditions that support
  distinctive plant and animal species

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Topics on Ecosystem Structure

• Trophic categories
• Trophic relationships food chains, food webs,
  trophic levels
• Nonfeeding relationships symbiosis
• Abiotic factors

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Autotrophs Producers Self feeders
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Inorganic and Organic

• Inorganic
• Oxygen
• Carbon dioxide
• Nitrogen
• Water
• pH

• Organic
• All living things
• Products of living things

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Consumers Heterotrophs

• Primary consumers herbivores rabbits eat
  plant material
• Secondary consumers carnivores predators
  coyotes prey are herbivores and other animals
• Parasites predator either plant or animal
  prey are plants or animals
• Detritus feeders and decomposers bacteria and
  fungi prey are plants or animals

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Trophic Categories
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Trophic Levels Food Chain
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Match Organisms with Trophic Level(s)
Trophic Levels Trophic Levels Trophic Levels Trophic Levels
Organisms Producer Primary Consumer Secondary Consumer Third-Order Consumer
Plants X
Rabbits X
Snakes X X
Owls X X
Bacteria X X X X
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Match Organisms with Trophic Level(s)
Trophic Levels Trophic Levels Trophic Levels Trophic Levels
Organisms Producer Primary Consumer Secondary Consumer Third-Order Consumer
Autotrophs X
Herbivores X
Carnivores X X
Omnivores X X X
Parasites X X X
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Trophic Relationships among Producers and
Consumers
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Food Webs
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Trophic Level Energy Flow
10,000 Kcal
Producer
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Trophic Levels Pyramid of Biomass
Which level is occupied by producers? primary
consumers? secondary consumers? third-order
consumers?
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Trophic Levels Pyramid of Energy
Which level is occupied by producers? primary
consumers? secondary consumers? third-order
consumers?
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Symbiosis Living Together

• and Mutualism. Both species benefit by the
  interaction between the two species yucca plant
  and Pronuba moth
• and 0 Commensalism. One species benefits from
  the interaction and the other is unaffected
  remora fish and shark

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Symbiosis Living Together

• and One species benefits from the
  interaction and the other is adversely affected.
  Examples are predation, parasitism, and disease.
• and Competition. Both species are adversely
  affected by the interaction.

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Resource Partitioning
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Law of Limiting Factors
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Application of the Law of Limiting Factors

• Compare the tolerance differences for a trout
  and a catfish using water
• temperature (cold or warm).
• oxygen concentration (high or low).
• salinity (high or low).

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From Ecosystems to Global Biomes

• The role of climate
• Microclimate and other abiotic factors
• Biotic factors
• Physical barriers

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Climate and Major Biomes
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Identify Biomes A to E Based on Temperature and
Precipitation Levels Answers on Next Slide
Precipitation
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Answers to Previous Slide

• A has high temperature and low moisture hot
  desert
• B has low temperature and low moisture cold
  desert (tundra with permafrost)
• C has medium temperatures and moisture
  grassland
• D has high temperature and moisture rain forest
• E has low temperature and high precipitation
  arctic poles

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Abiotic Effects of Latitude and Altitude
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The Human Factor

• Three revolutions
• Neolithic
• Industrial
• Environmental

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How Humans Modify Their Physical Environments to
Meet Their Needs

• Produce abundant food
• Control water flow rate and direction
• Overcome predation and disease
• Construct our own ecosystems
• Overcome competition with other species

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End of Chapter 2