Chapter 4: Ecosystems: Components, Energy Flow and Matter Cycling

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Chapter 4 Ecosystems Components, Energy Flow
and Matter Cycling
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I. What is Ecology?

• The Study of how Organisms interact with one
  another
• and
• How they interact with their non-living
  environment

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Organization on the Planet

• Ecosystem Organization
• 1. Organism
• Any Living thing
• 2. Population
• Group of interacting Individuals of the same
  species

Fig. 4.2, p. 72
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• 3. Community
• Populations of all the different species occupy a
  particular place
• 4. Ecosystem
• Community of different species interacting with
  one another
• 5. Biosphere
• All of the Earths Ecosystems

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II. Biomes and Aquatic Life Systems

• A. Biomes
• Land portion of the biosphere
• Distinct climate and specific life-forms adapted
  for life within that climate.
• Climate - long-term patterns of weather is the
  primary factor determining the type of life
• B. Aquatic life zones
• Marine and Freshwater

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Ecosystem Concepts and Components
Fig. 4.9, p. 76
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C. Ecotone

• Transitional zone between two ecosystems
• A mixture of species found in both ecosystems as
  well as organisms that are unique to the
  ecotones.

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Ecosystem Boundaries Ecotones
Fig. 4.10, p. 77
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• III. COMPONENTS OF AN ECOSYSTEM
• ABIOTIC
• Non-living components
• (Water, air, nutrients and solar energy)
• 2. BIOTIC
• Living components
• (Plants, animals, microorganisms)

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• 1. Abiotic Ecological Factors
• -Each population within an ecosystem has a RANGE
  OF TOLERANCE to abiotic factors

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A. Range of Tolerance

• Minimum and maximum Range in which physical and
  chemical variations can be tolerated
• Individuals in a population may have different
  levels of tolerance
• Due to genetics, health and age
• Most susceptible during juvenile and reproductive
  stages

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B. Limiting Factor

• The one factor that is most important in
  regulating population size
• Limiting Factor Principle
• Too much or too little of any abiotic factor can
  limit a population

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ABIOTIC FACTORS

• Sunlight
• Temperature
• Precipitation
• Wind
• Altitude
• Fire frequency
• Soil

• Water currents
• Dissolved nutrient concentration (O,N,P)
• Salinity
• Suspended solids

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• 2. Main BIOTIC factors within an ecosystem
• -All the living organisms sustain their existence
  by the process of METABOLISM.
• -2 Options
• A. PRODUCERS AUTOTROPHS
• B. CONSUMERS - HETEROTROPHS

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A. AUTOTROPHS

• -Organisms that have the ability to make their
  own food
• PHOTOSYNTHESIS

CHEMOSYNTHESIS
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B. HETEROTROPHS
Organisms that have to get their food from other
sources.

• Primary consumer (herbivore)

• Secondary/Tertiary consumer (carnivore)

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• Omnivore Plants and Animals

2 Consumer
1 consumer
Producer
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• Detritivores and scavengers Parts of dead
  organisms or their wastes
• Decomposers Breakdown dead
• material (recycle)

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• AEROBIC RESPIRATION
• Process of using Oxygen to break down glucose
• ANAEROBIC RESPIRATION
• Breaking down Glucose without Oxygen

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Producers / Consumers
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The Biotic Components of Ecosystems

• Producers

• Consumers

• Decomposers

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IV. Ecological Niches and Adaptation

• NICHE
• The role that an organism plays in an ecosystem
• -HABITAT
• the actual physical location where a species
  lives.
• -Two main types of Niches
• A. Generalist
• B. Specialist

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• A. Generalist Species
• Broad niches
• Ex Flies, cockroaches, mice, rats, white-tailed
  deer, raccoons, channel catfish and humans

• B. Specialists
• Narrow niches
• Ex Spotted Owls, Giant Panda Bear

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Is it better to be a generalist or a specialist?

• Benefits to specialists
• If conditions are constant there is fewer
  competitors
• Benefits to generalists
• Can adapt easier if the conditions are rapidly
  changing

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Generalist Species vs. Specialist Species
Niche separation
Niche breadth
Resource use
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Fundamental vs. Realized Niche

• Fundamental Niche
• Full potential range of conditions
• Realized Niche
• Occupies part of the fundamental niche to avoid
  competition

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V. ENERGY TRANSFER

• Food Chains, Webs, and Trophic Levels
• 1. Food Chain
• Sequence of organisms, each of which is a food
  source for the next.
• Shows how energy and nutrients move from one
  organism to another through the ecosystem.

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• 2. Food Web-
• -A complex network of interconnecting food chains
  showing the relationship of many organisms within
  an ecosystem.
• 3. Energy Pyramid/Trophic Levels-
• A step in the transfer of energy through an
  ecosystem
• The level of a food chain that an organism
  occupies.

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ENVIRO ENERGY
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B. Biomass and Energy Flow

• Each level contains a certain amount of biomass
• The dry weight of all organic matter in an
  organism.
• 1.) Only a small of what is eaten is converted
  into biomass
• 2.) The amount of usable energy decreases at
  each trophic level

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FOOD CHAINS AND WEBS
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Ecological Efficiency

• of usable energy transferred from level to
  level
• Typically 5-20
• Pyramid of Energy Flow Explains why
• 1.) So few top carnivores
• 2.) Why these species are the first to suffer
  when there is disruption
• 3.) Why they are vulnerable to extinction

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Ecological Pyramids
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Pyramids of Biomass and Numbers

• Storage of biomass at each level
• Organisms are sorted, dried and weighed
• Most land ecosystems have a reduction in biomass
  at each level
• There may be more primary consumers in an open
  ocean
• Photoplankon is small and is eaten as soon as it
  is produced

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VI. Primary Productivity of Ecosystems

• Gross primary productivity (GPP)

• Net primary productivity (NPP)

Fig. 4.25, p. 88
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• Gross Primary Productivity (GPP)
• Rate that producers convert solar energy into
  biomass
• Usually greatest in
• Shallow Waters
• Coral Reefs (abundant light, heat and nutrients)
• Upwellings (Currents bring up nutrients from the
  ocean bottoms)
• Least in
• Deserts
• Open ocean

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Net Primary Productivity

• Producers must use some of the total biomass they
  produce for respiration
• NPP is what is left as available food.

Net Primary Productivity Energy stored - Energy
used (Photosynthesis) - (Respiration)
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Why Not Use the Most Productive Regions to Feed
the Human Population?

• Most swamp/marsh foods are not fit for human
  consumption
• Most of the nutrient of a tropical forest are
  stored in the vegetation
• Energy requirements of harvesting food from the
  oceans are too high
• It would deplete vital sources of food for other
  forms of life and alter the food webs

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How much of the Worlds Net Biomass Do we Use?

• Humans have taken over a degraded 73 of the
  Earths land surface
• Humans use, waste or destroy 40 of the net
  primary productivity
• What may happen if the human population doubles
  over the next 40-50 years?

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