Transcript Notes #1

Chapter 3
Notes #1
Energy Flow in
Producer – an organism that makes its own food
 Also called an autotrophy “self-feeders”
Consumer – an organism that gets its food by eating
other organisms
 Also called “heterotrophs”
In your group discuss the following 3 statements
Almost all organisms get their energy from the sun
Producers get their energy directly from the sun
Consumers get their energy indirectly from the sun
Energy Flow in
 Exception to the rule – Deep-water
 No sunlight = No photosynthesis
 Some bacteria make food from hydrogen
 H2SO4 escapes from cracks in the ocean
 The bacteria become the producers
Energy Flow in
 What Eats What…
 Herbivore – plant eater
 Consumers that eat only producers
 Carnivore – meat eater
 Consumers that only eat other consumers
 Omnivores – plant + meat eater
 “Eaters of all”
 Decomposers – dead organisms
 Get food by rotting dead organisms
Energy Flow in
 photosynthesis
 6CO2 + 6H2O + light energy  C6H12O6 + 6O2
 Cellular Respiration
 The process of breaking down food to yield
 Cellular respiration
 C6H12O6 + 6O2  6CO2 + 6H2O + energy
 If you look closely you can see that the two processes
are opposites of one another.
Energy Flow in
 Even organisms that use photosynthesis to
make food use cellular respiration to obtain
energy from the food.
 All living organisms use cellular respiration to
obtain energy from food molecules
 Every time one organism eats another
organism energy gets transferred…this transfer
can be traced thru food chains, food webs, and
trophic levels.
Energy Flow in
 Food Chains/Food Webs
 Food Chain – a sequence in which energy is
transferred from one organism to another as
each organism eats another.
 Ecosystems are more complicated than a
simple food chain.
 Food Web - Shows many of the feeding
relationships in an ecosystem.
Energy Flow in Ecosystems
Energy Flow in Ecosystems
Energy Flow in Ecosystems
 Trophic levels
 Shows each step in the transfer of
 Ex. The previous food chain
 Algae – the bottom trophic level
 Krill – the next up trophic level
 Each time energy is transferred, less is
available to the organisms at the next
trophic level
Energy Flow in Ecosystems
 This relationship can be shown with an energy
 Producers form the base of the pyramid (lowest level)
 Herbivores = next level = primary consumers
 Carnivores that eat herbivores = secondary
 Carnivores that eat other carnivores= tertiary
 Pyramids get smaller at the top, less energy at top
 Energy loss results in fewer organisms at the higher
trophic levels
Energy Flow in Ecosystems