Food Chain and Food Food Chain and Food WebsWebs

Ms. McGrathScience 10

Food ChainsFood ChainsGrass grasshopper robin hawk

Producer: makes its own food through photosynthesis which uses energy from the sun

Autotroph: auto = self, troph = food

Energy transfer (10% passed on at each step)

Primary consumer: eat producers

Herbivore: only eat plants

Heterotroph: hetero = others, troph = food

Secondary consumer

Tertiary consumer

DefinitionsDefinitionsOmnivore: eats everything (plants

and meat)Example: Humans, brown bears

Carnivore: only eats meatExample: Lions

Scavengers: eat dead things, don’t kill preyExample: Vultures, raccoons

Decomposers: consume dead material and recycle (return) nutrients to the soilExample: Worms, bacteria, fungi

Trophic LevelsTrophic LevelsFirst trophic level = producers (plants)

Second trophic level = primary consumers (herbivores)

Third trophic level = secondary consumers (carnivores)

Fourth trophic level = tertiary consumers

In which trophic level do In which trophic level do each of the following each of the following organisms belong?organisms belong?

grasscrowcoyotemaple treebacteriasnakemousedeerporcupine red squirrelseeds

ProducersProducers Primary Primary consumersconsumers

Secondary Secondary consumers/consumers/

DecomposersDecomposers

EnergyEnergyWhat is the primary source of

energy for all food chains?

Food Web: many food chains Food Web: many food chains interlinkedinterlinked

Identify 3 food chains in the food web below

deer

grass

shrubs

insect

frog

hawk

snake wolf

rabbit

mouse

Abiotic vs. bioticAbiotic vs. bioticAbiotic factors: components of

an ecosystem that are non-living Example: soil, water, sunlight

Biotic factors: components of an ecosystem that are, or use to be, livingExample: trees, birds, insects, bacteria

Complete the diagram using the following terms : Complete the diagram using the following terms : primary consumer (herbivore) , secondary consumer primary consumer (herbivore) , secondary consumer (carnivore), tertiary consumer, decomposers, second (carnivore), tertiary consumer, decomposers, second trophic level, first trophic level, producer, fourth trophic trophic level, first trophic level, producer, fourth trophic level, third trophic levellevel, third trophic level

Transfer of EnergyTransfer of Energy

Food energy ingested by a consumer is used for many processes.

Only around ____ % is

converted into body mass.

Why do we rarely see more than 4 links in a food chain?

Organisms are Organisms are interconnectedinterconnected Look at the following food chain : Grass Deer Wolf

If the deer population increases, what would happen to:

The grass population? The wolf population?

The grass population would decrease

The wolf population would increase because:

More food increases reproductive rates (more babies)

Eventually, the wolf population would start to decrease because food would run out

DefinitionsDefinitionsEcosystem: interactions among

organisms and their environment

Sustainable ecosystem: able to handle pressure and support many different organisms

Day 2 QuestionsDay 2 Questions1. Which type of organism is at the

beginning of all food chains?2. Which organisms can eat all other

organisms?3. In an ecosystem, the abiotic factors

include…?4. 3 examples of decomposers are …?5. What is the importance of decomposers

in an ecosystem?6. What is the principal source of energy for

all ecosystems?