Objectives

1
Objectives

• Describe how energy is transferred from the sun
  or other energy sources to producers and then to
  consumers
• Describe how consumers depend on producers
• List and identify types of consumers
• Explain how energy transfer in a food web is more
  complex than energy transfer in a food chain
• Explain why an energy pyramid is a representation
  of trophic levels

2
What is made out of the following ingredients?

• ½ bathtub of oxygen
• 50 glasses of water
• ½ cup sugar
• ½ cup calcium
• 1/10th thimbleful of salt
• a small pinch of assorted elements such as
  phosphorus, potassium, nitrogen, sulfur,
  magnesium, and iron
• a mystery ingredient

What is the mystery ingredient?
Where does that energy come from?
Where does the energy in food come from?
3
Life Depends on the Sun

• Almost every living organism gets its energy from
  the sun.
• Energy from the sun enters an ecosystem when
  plants use sunlight to make sugar molecules.
• This happens through a process called
  photosynthesis.

4
Life Depends on the Sun

• Photosynthesis is the process by which plants,
  algae, and some bacteria use sunlight, carbon
  dioxide, and water to produce carbohydrates and
  oxygen.

5
From Producers to Consumers

• Because plants make their own food, they are
  called producers.
• A producer is an organism that can make organic
  molecules from inorganic molecules.
• Producers are also called autotrophs, or
  self-feeders.
• Examples?

6
From Producers to Consumers

• Organisms that get their energy by eating other
  organisms are called consumers.
• A consumer is an organism that eats other
  organisms or organic matter instead of producing
  its own nutrients or obtaining nutrients from
  inorganic sources.
• Consumers are also called heterotrophs, or
  other-feeders.
• Examples?

7
From Producers to Consumers

• Most producers get their energy directly from the
  sun by absorbing it through their leaves.
• Consumers get their energy indirectly by eating
  producers or other consumers.

8
An Exception to the Rule

• Deep-ocean communities of worms, clams, crabs,
  mussels, and barnacles, exist in total darkness
  on the ocean floor, where photosynthesis cannot
  occur.
• Mr. Holtien, show the clip!
• The producers in this environment are bacteria
  that use hydrogen sulfide (H2S) or methane (CH4)
  present in the water. (Chemosynthesis)
• Other underwater organisms eat the bacteria or
  the organisms that eat the bacteria.

9
Chemosynthesis
10
What Eats What?

• Organisms can be classified by what they eat.
• Types of Consumers
• Herbivores
• Carnivores
• Omnivores
• Decomposers
• Definition and Examples of each?

11
(No Transcript)
12
Burning the Fuel

• An organism obtains energy from the food it eats.
• This food must be broken down within its body.
• The process of breaking down food to yield energy
  is called cellular respiration.

13
Burning the Fuel

• Cellular Respiration is the process by which
  cells produce energy from carbohydrates
  atmospheric oxygen combines with glucose to form
  water and carbon dioxide.
• Cellular respiration occurs inside the cells of
  most organisms.

14
Burning the Fuel

• During cellular respiration, cells absorb oxygen
  and use it to release energy from food.
• Through cellular respiration, cells use glucose
  (sugar) and oxygen to produce carbon dioxide,
  water, and energy.

15
What is the relationship between photosynthesis
and cellular respiration?
16
Does all of the energy you consume through food
get stored in your body?

• About 10 of the food you eat is stored as
• Cells (bone, muscle, fat, other tissue)
• Reproductive tissues (sperm, eggs, children)
• About 90 of the food you eat is used or lost as
• Locomotion
• Breathing
• Body waste
• Body heat

17
Energy Transfer

• Each time an organism eats another organism, an
  energy transfer occurs.
• This transfer of energy can be traced by studying
  food chains, food webs, and trophic levels.

18
Food Chains

• A food chain is a sequence in which energy is
  transferred from one organism to the next as each
  organism eats another organism.

19
Food Chains
What happens to the amount of organisms at each
level as you move up the food chain?
What happens to the total amount of energy as you
move up the food chain?
20
Food Webs

• Ecosystems, however, almost always contain more
  than one food chain.
• A food web shows many feeding relationships that
  are possible in an ecosystem.

21
Food Webs
What is more realistic a food chain or food web?
22
Trophic Levels

• Each step in the transfer of energy through a
  food chain or food web is known as a trophic
  level.
• A trophic level is one of the steps in a food
  chain or food pyramid examples include
• Producers
• Primary consumers
• Secondary consumers
• Tertiary consumers

23
Trophic Levels in an Energy Pyramid
24
Which level contains the greatest amount of
individual organisms?
25
Which level contains the smallest amount of
energy?
26
Can there be unlimited trophic levels in an
ecosystem?