How Ecosystems Work

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How Ecosystems Work

• Energy flow
• Cycling of materials
• How ecosystems change

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Energy Flow

• All living things have a different job in the
  ecosystem. Each does their job and interacts with
  other organisms and the environment.

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This decides their roles in the ecosystem.
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Energy

• Living organisms need to get energy to run their
  body functions. Each gets energy from the
  environment but from different ways.

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Energy

• The ultimate source of energy is the sun.

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Producers

• Organisms that make their own food.
• Also called autotrophs.
• Use photosynthesis to make sugars. (chemical
  energy)

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Producers

• Some use sources other than the sun.
  (chemotrophs)
• Examples plants, algae, some bacteria,
  aquatic organisms.

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Consumers

• Cannot make their own food. They must eat to
  obtain energy.

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Consumers

• Also called heterotrophs.
• Use cellular respiration to break down sugars
  into useful energy.

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Decomposers

• Cannot make their own food.
• Eat dead organisms and waste products.
• Return atoms to the soil to be reused.
• Examples fungi bacteria

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Roles Within an Ecosystem
CARNIVORE!
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Levels of Organization
In the food chain there are organisms that make
food and those that eat food. These levels are
called trophic levels
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Food Chain

• Sequence in which energy is transferred from one
  organism to the next.

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Food Web

• Shows many feeding relationships within an
  ecosystem.

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Energy Pyramid

• Shows how energy is lost from one trophic level
  to the next.

ENERGY DECREASES
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Energy Pyramid
Trophic Levels
Secondary consumers
Primary consumers
Producers
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Levels of Organization

• Producers are always at the bottom of the food
  chain or pyramid. Able to produce their own food.
• Example plants

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Levels of Organization cont.

• Primary Consumer eats producers.
• Also known as herbivores.
• Body designed to gather, grind and digest plants.
• Example insects, birds and cows (grazers)

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Levels of Organization cont.

• Secondary consumer- eats primary consumers

• Also known as a carnivore (meat- eater)

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Levels of Organization cont.

• Body designed to hunt and catch prey. (sharp
  fangs and incisors to cut and rip meat claws)
• Examples dogs, eagles, lion

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Levels of Organization cont.

• Tertiary consumer eats a secondary consumer. A
  carnivore that eats carnivores.
• Examples Eagles, Tigers

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Levels of Organization cont.

• Omnivore eats both producers and consumers.
• Examples
• humans,
• chimpanzees,
• bears.

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Levels of Organization cont.

• Scavenger (decomposer) do not hunt living prey.
  Consume dead and decaying matter.

Example Vultures and Hyenas
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Cycles in Our Environment

• There are many cycles that create the ideal
  conditions for living and non living things
  within our biosphere.

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The water cycle

• Broken down during photosynthesis
• Created during respiration
• Energy that runs the cycle is provided by the sun

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The water cycle

• Water is evaporated from the surface of the earth
  and accumulates in the atmosphere.
• Water vapor condenses and is released back to the
  earths surface as precipitation.

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The carbon cycle

• Carbon is a necessary component for all life.
  (Fats, carbohydrates and proteins)
• Enters the ecosystem through photosynthesis

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The carbon cycle

• Consumers obtain carbon by eating producers
• Carbon is released back into the atmosphere via
  carbon dioxide.

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The nitrogen cycle

• Used to produce proteins
• Makes up approx. 78 of the atmosphere

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The nitrogen cycle

• Very few species can use the nitrogen directly
  from the atmosphere. (Nitrogen- fixing bacteria
  fungi)

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The nitrogen cycle

• Plants obtain nitrogen from the soil
• Animal obtain nitrogen from eating plants and
  other animals

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Changes Within an Ecosystem

• Ecological succession changes within an
  environment over a period of time. It can be
  changes in the organisms, changes in the habitat
  or plant life.

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Primary Succession

• Occurs in two stages
• Pioneer Communities are the first communities to
  colonize a new habitat.
• Example Lichen

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Primary Succession

• Begins in areas where there is no life. The first
  step in primary succession is the formation of
  soil and other organic materials form rock and
  soil.

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Primary Succession

• Climax Communities are the final stages of a
  habitat.
• Usually diverse and stable.
• Will not undergo changes unless it is disturbed.
• Some communities never reach a climax because
  they are constantly undergoing change.

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Secondary Succession

• Occurs where a community has been cleared by a
  disturbance that does not destroy the soil.

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Secondary Succession

• Usually beings as a result of a natural disaster
  like fire or human activity.