GHSGT Science Review

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GHSGT Science Review

• Domain 2 Ecology
• Food Chains, Food Webs, and the Transfer of
  Energy
• Ppt. 2

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Ecology

• Levels of Organization

the study of the interactions
between among the biotic abiotic factors in
an area.
Ecology
all of the ecosystems on earth areas
of earth where life exists.
Biosphere
all of the communities the abiotic
factors in a given area.
Ecosystem
all of the populations in a
given area at a particular time.
all members of the same species in a
given area at a given time.
group of similar organisms that can
reproduce fertile offspring.
Species
Population
Community
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Autotrophs

• A groups of organisms that can use the energy in
  sunlight to convert water and carbon dioxide into
  glucose (photosynthesis)
• Autotrophs are also called Producers because they
  produce all of the food that heterotrophs use
• Without autotrophs, there would be no life on
  this planet
• Ex. Plants and Algae

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Autotrophs
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Autotrophs

• Chemotrophs
• Autotrophs that get their energy from inorganic
  substances, such as salt
• Live deep down in the ocean where there is no
  sunlight
• Ex. Bacteria and Deep Sea Worms

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Heterotrophs

• Organisms that do not make their own food
• Another term for Heterotroph is consumer because
  they consume other organisms in order to live
• Ex. Rabbits, Deer, Mushrooms, and Us

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Heterotrophs
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Heterotrophs

• Consumers
• 1. Scavengers/Detritivores feed on the tissue
  of dead organisms (both plans and animals)
• Ex. Vultures, Crows, and Shrimp

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Heterotrophs

• Consumers
• 2. Herbivores eat ONLY plants
• Ex. Cows, Elephants, Giraffes

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Heterotrophs

• Consumers
• 4. Omnivores eat BOTH plants and animals
• Ex. Bears and Humans

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Heterotrophs

• Consumers
• 3. Carnivores eat ONLY meat
• Ex. Lions, Tigers, Sharks

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Heterotrophs

• Consumers
• 5. Decomposers absorb any dead material and
  break it down into simple nutrients or
  fertilizers
• Ex. Bacteria and Mushrooms

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Energy Flow
producers(autotrophs)
consumers(heterotrophs)
energy

• Organisms that can produce their own
• food .

Autotrophs
Heterotrophs
Organisms that must get their food by consuming
other organisms.
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the level(s) at which an organism feeds
withinits ecosystem
Tophic Level
Tertiary consumers
Heterotrophs
Secondary consumers
Primary Consumers
Autotrophs
Producers
Ecological pyramid
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Principles of Ecology
Chapter 2
2.2 Flow of Energy in an Ecosystem
Models of Energy Flow

• Food chains and food webs model the energy flow
  through an ecosystem.

• Each step in a food chain or food web is called a
  trophic level.

Model Ecosystems
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Principles of Ecology
Chapter 2
2.2 Flow of Energy in an Ecosystem
Food Chains

• A food chain is a simple model that shows how
  energy flows through an ecosystem.

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Principles of Ecology
Chapter 2
2.2 Flow of Energy in an Ecosystem
Food Webs

• A food web is a model representing the many
  interconnected food chains and pathways in which
  energy flows through a group of organisms.

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Transfer of Energy

• When a zebra eats the grass, it does not obtain
  all of the energy the grass has (much of it is
  not eaten)
• When a lion eats a zebra, it does not get all of
  the energy from the zebra (much of it is lost as
  heat)

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Transfer of Energy

• The two (2) previous examples of energy transfer
  show that no organism EVER receives all of the
  energy from the organism they just ate
• Only 10 of the energy from one trophic level is
  transferred to the next this is called the 10
  law

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Trophic Levels

• Energy moves from one organisms to another when
  it is eaten
• Each step in this transfer of energy is know as a
  trophic level
• The main trophic levels are producers, consumers,
  and decomposers

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Food Chains

• The energy flow from one trophic level to the
  other is know as a food chain
• A food chain is simple and direct
• It involves one organism at each trophic level
• Primary Consumers eat autotrophs (producers)
• Secondary Consumers eat the primary consumers
• Tertiary Consumers eat the secondary consumers
• Decomposers bacteria and fungi that break down
  dead organisms and recycle the material back into
  the environment

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Food Chain
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Food Web

• Most organisms eat more the JUST one organism
• When more organism are involved it is know as a
  FOOD WEB
• Food webs are more complex and involve lots of
  organisms

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Food Web
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Food Web

• Notice that the direction the arrow points ? the
  arrow points in the direction of the energy
  transfer, NOT what ate what

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Food Web
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Biomass

• The total mass of the organic matter at each
  trophic level is called biomass
• Biomass is just another term for potential energy
  energy that is to be eaten and used.
• The transfer of energy from one level to another
  is very inefficient (10 Law)

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Biomass
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Ecological Pyramid

• An ecological pyramid shows the relationship
  between consumers and producers at different
  trophic levels in an ecosystem
• Shows the relative amounts of energy or matter
  contained at each trophic level
• The Pyramid shows which level has the most energy
  and the highest number of organisms

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Ecological Pyramid
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Ecological Pyramid
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Ecological Pyramid

• Which level has the most energy?
• Which level has the most organisms?
• Which level has the least organisms?
• Which level has the least energy?

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Symbiosis

• A close and permanent association between
  organisms of different species
• Commensalism a relationship in which one
  organism benefits and the other is not affected
• Example Barnacles on a whale
• Mutualism a relationship in which both
  organisms benefit from each other
• Example Birds eating pest off a rhinos back
• Parasitism A relationship in which one organism
  benefits and the other is harmed
• Example Ticks on a dog

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Ecological Succession

• A change in the community in which new
  populations of organisms gradually replace
  existing ones
• 1. Primary Succession occurs in an area where
  there is no existing communities and for some
  reason (s) a new community of organisms move into
  the area

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Ecological Succession

• A change in the community in which new
  populations of organisms gradually replace
  existing ones
• 2. Secondary Succession occurs in an area
  where an existing community is partially damaged

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Ecological Succession

• A change in the community in which new
  populations of organisms gradually replace
  existing ones
• 3. Climax Community a community that is stable
  and has a great diversity of organisms