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?