Energy Flow in Ecosystems

1
Energy Flow in Ecosystems

• Food Chains and Food Webs

2

• What process does the following chemical equation
  represent?
• CO2 H2O ? C6H12O6 O2
• Why is this process important in ecosystems?

3
Energy Flow

• Every living things needs energy to survive
• What is the ultimate source of energy?
• The sun
• Life depends on the Sun
• Plants, algae and some bacteria capture solar
  energy photosynthesis
• Solar energy combined with carbon dioxide and
  water make a high energy molecule (sugar) which
  is the foundation for the flow of energy through
  an ecosystem
• CO2 H2O solar energy? C6H12O6 O2

4
Producers- organisms that produce their own food
(Autotrophs) Consumers- organisms that get
energy from eating other organisms
(Heterotrophs) Producers get energy directly
from the sun, consumers gain energy indirectly
from other organisms EXCEPTION Deep Ocean
Ecosystems bacteria make food from hydrogen
sulfide (chemosynthesis) that is released from
the ocean floor, provide food for other
organisms
5
Right-deep ocean crabs Left-Tube Worms
Anglerfish
Rattail Fish
6
What Eats What
Name Energy Source Examples
Producer Sun Hydrogen Sulfide Plants, bacteria
Consumer From other organisms Cows, sheep, deer, bears
Herbivores Plant eaters Cow, deer, rabbits
b. Carnivores Meat eaters Hawk, lions, spiders
c. Omnivores Meat and plant eaters Bears, humans, pigs
d. Decomposer Breaks down dead organisms Fungi and bacteria
7
How is energy used?

• Organisms break down their food to
• yield (obtain) energy by a process called
  cellular respiration
• C6H12O6 O2 ? CO2 H2O energy
• What is energy used for? (discuss and list)

8
Energy Transfer Food Chains

• When one organism eats another organism, there is
  a transfer of energy
• Food Chain- sequence in which energy is
  transferred from one organism to another as they
  eat each other

very simplified Poisons can also be transferred-
DDT
9
Types of Consumers

• Primary- first consumer herbivores
• Secondary- second consumer carnivore
• Tertiary- third consumer carnivore
• Secondary and tertiary consumers may also be
  omnivores

10
Producer Primary Consumer SecondaryConsumer
11
Energy Transfer Food Webs

• Food Web- a more accurate account consisting of
  many food chains between species in the same
  ecosystem
• The more complex a food web, the more stable an
  ecosystem is Why?
• Arrows show direction of energy

Alaskan Marine Food Web
12
Trophic Levels

• Trophic level- transfer of energy through an
  ecosystem
• Every time energy is transferred, less of it is
  available to the organism on the next level
• Loss of energy occurs
• During the process of converting food to energy
• Used by organism to live
• 90 of energy from food is used by organism
• 10 is available for the next trophic level

13
Energy is lost from one trophic level to the next
1
10
100
1,000
10,000
Why are there fewer organisms at the top of the
pyramid? What role does sunlight play in an
ecosystem?
Energy Pyramid Trophic levels
14

• Choose an organism you are familiar with and
  create a food web using at least 10 organisms,
  including the sun on cardstock (20 points)
• You can draw organisms or write names- use your
  book for examples but do not copy
• Must be organisms in the same ecosystem (a lion
  cannot eat a deer since they live in different
  ecosystems)
• On back of food web
• Define biomass (5points)
• Look up definition of Population Explosion and
  answer What effect would a population explosion
  of your primary consumer have on your food web?
  (10 points)