Communities!
• All around us are organisms (living things)
living in communities, e.g. in NZ native bush.
• Each species has its own population within
the community, and a niche where it lives.
• Producers – Organisms that make their own
food from sunlight energy
– Examples: plants, trees, moss, algae
• Consumers – Organisms that eat other
organisms (plants or animals)
– Examples: caterpillars, bugs, birds, dogs,
possums, fish, frogs, humans
• Decomposers – Organisms that break down
the bodies of dead organisms and waste
– Examples: bacteria and fungi
Different types of consumers
• Carnivores – only eat other animals
• Herbivores – only eat plants
• Omnivores – eat plants and animals
Food chains
• A community contains many food chains which link up
to form a food web
• e.g. grass  sheep  human
• Each step in the food chain is called a trophic level.
• It shows “who eats who”
• Energy flows from the lowest trophic level to the
highest trophic level. Energy enters the chain as light
and exits as heat.
• The arrow shows the direction of energy flow
• Only 10% of energy flows from one level to the next.
The other 90% is converted to heat.
Trophic levels
grass  grasshopper  birds  cats
• Grass is the…..
• Consumers can be first order
(herbivores), second or third
order (omnivores and
carnivores), and higher!
• Grasshopper is the…..
• Birds are the….
• Cats are the….
Third-order
consumer
Second-order
consumer
First-order
consumer
Producer
Trophic levels
grass  grasshopper  birds  cats
• Grass is the producer
• Consumers can be first order
(herbivores), second or third
order (omnivores and
carnivores), and higher!
• Grasshopper is the first-order
consumer
• Birds are the second-order
consumers
• Cats are the third-order
consumers
Third-order
consumer
Second-order
consumer
First-order
consumer
Producer
T6 Carnivores (fourthorder consumers
T5 Carnivores
(third-order
consumers)
T4 Omnivores and
Carnivores (secondorder consumers)
Seals
Sea birds
Penguins
Fish
Krill
shrimp
T2 Herbivores
(first-order
consumers)
T1 Producers
Baleen
whales
Squid
T3 Omnivores
(second-order
consumers)
Animal
plankton
T=Trophic Level
Plant
plankton
Sperm
whales