How does Energy Flow through our Biosphere

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How does Energy Flow through our Biosphere?
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1. Energy flow through trophic levels
a. Each step in a food chain/web is called a
trophic level
b. As organisms receive energy in its trophic
level, some of that initial energy is used to
maintain life.
i. Remaining energy is passed on through the
food chain/web.
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i. Illustrates how much energy is lost at each
level of consumption
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2. Biomass found at each trophic level
a. The amount of living organic matter at
each trophic level.
i. Typically, the greatest biomass is at the
base of the pyramid.
ii. Represents the amount of potential food
available at each tropic level in an
ecosystem
i. Illustrates how much living organic matter
exists at each trophic level
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3. Number of individuals found at each trophic
level
i. Illustrates the relative number of
individual organisms at each trophic level.
ii. Typically the bottom of the pyramid has
more individuals, but not always! ex A
forest has fewer autotrophs than consumers. A
tree may have large biomass but only counts as
one individual.
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Least amount of energy Least amount of
biomass Smallest populations
Less energy Less biomass
Smaller populations
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Direct Relationship to Food Chains/Webs

• Each organism in the chain represents a feeding
  step or TROPHIC LEVEL
• Can be represented by ecological pyramids

Top carnivores
carnivores
Herbivores
Energy Pyramid
Producers
Biomass pyramid or pyramid of numbers
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What Shapes an Ecosystem?
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Ecosystems

• Ecosystem made up of the interactions among the
  populations in a community AND the communitys
  physical factors

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• Ecosystems are influenced by a combination of
  biological and physical factors.

1. Biotic factors
a. Biological influences on an organism
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2. Abiotic factors
a. Physical, non-living influences on an
organism
i. An organisms interactions with non- living
things within an ecosystem
ii. Includes temperature, air, water,
landforms, sunlight, wind, etc.
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B. Together abiotic and biotic factors determine
1. The survival and growth of an organism
C. The full range of physical and biological
conditions in which an organism lives is called
its niche.
1. Includes how an organism uses those
physical and biological conditions within its
habitat.
2. Affected by its tolerance range
a. Ex temperature range needed for survival
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a. Can have similar niches
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Three Species of Warblers and Their Niches
Cape May Warbler Feeds at the tips of
branches near the top of the tree
Bay-Breasted Warbler Feeds in the middle part of
the tree
Yellow-Rumped Warbler Feeds in the lower part of
the tree and at the bases of the middle branches
Spruce tree
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Limiting factors

• Def any environmental factor (whether abiotic
  or biotic) that restricts the existence, numbers,
  reproduction, or distribution of organisms in an
  ecosystem.
• (Ex. Amount of food, predators, temperature)

• Factors that limit one population may also have
  an indirect effect on another population.

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Primary Productivity

• Rate at which organic matter is created by
  producers.

• Nutrient availability often controls this, so
  farmers will add nutrients to their soils
  FERTILIZER!!!

• If a single nutrient is scarce or cycles very
  slowly, it is called a LIMITING NUTRIENT.
• -ex. Nitrogen in sea water

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What is Succession?
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• Ecosystems are constantly changing

2. As change occurs, older inhabitants usually
die out and new organism move in
a. Causes a chain reaction of changes
3. Some changes within an ecosystem are
predictable
a. Ecological succession occurs in a
community over a period of time
i. Primary succession- occurs on land where
no soil exists.
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Primary Succession
Mosses and grasses begin to take root in thin
soil layer that formed from decaying lichens
Lichens begin to grow on bare rock. When they
die, they leave behind organic matter
Tree seedlings and shrubs begin to grow.
Newly exposed rock is barren and lifeless
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i. Secondary succession- occurs when a
disturbance changes and existing community
without removing the soil
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Primary vs. Secondary Succession

• When NEW sites are established as communities
  PRIMARY
• EX. Volcano erupts and forms a new island in
  the ocean

• When a pre-existing community is destroyed and
  then rebuilds SECONDARY

• Ultimate result of succession
• Climax community the stable, mature community
  that undergoes little or no change in species