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.

• 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….

Trophic levels

Producer

First-order consumer

Second-order consumer

Third-order consumer

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

Trophic levels

Producer

First-order consumer

Second-order consumer

Third-order consumer

grass grasshopper birds cats

Plant plankton

Animal plankton

Fish

Penguins

Krill shrimp

Baleen whales

Squid

Sea birds Sperm whales

Seals

T1 Producers

T2 Herbivores (first-order consumers)

T4 Omnivores and Carnivores (second-order consumers)

T5 Carnivores (third-order consumers)

T6 Carnivores (fourth-order consumers

T3 Omnivores (second-order consumers)

T=Trophic Level