Food Chain Notes

What is the difference between
habitat and niche?
Agenda for Tuesday Jan 5th
1. Finish/present posters
2. Food chains
• If an ecosystem is to be self-sustaining it must
contain a flow of energy.
• The pathways of energy through the living
components of an ecosystem are represented
by food chains and food webs.
Food Webs and Food Chains
• All energy starts with the SUN
• Producers – use sun’s energy
– Autotrophs – Make their own food
• Consumers – eat other organisms
– Primary – eat plants
– Secondary – eat primary consumers
– Tertiary – eat secondary consumers
Types of heterotrophs
• Herbivores – plant eaters
• Carnivores – meat eaters
• Omnivore – both meat and plants
• Detritivores – eat decomposing
matter (detritus)
• Decomposers – eat dead organisms
Food Chain
• Feeding relationships among organisms in an
– Results in energy transfer (shown by arrows)
Food Web
• Interrelated food chains
– Shows energy transfer
– More complex = more stable
Energy Pyramid
• Shows trophic (feeding) levels and energy available
to each level
– 10% energy gets passed to each level
– Lose 90% to living/respiration
Fill in the
levels of the
food chain
with the
passed on.
1 J of energy
10 J of energy
100 J of energy
1,000 J of energy
10,000 J of energy
Fill in the
levels of the
food chain
with the
passed on.
750,000 J of energy
Label the trophic levels (producer, primary
consumer, etc.) of each organism in the
food chain.
Agenda for Thursday Jan 7th
1. Go over homework/Food chain practice
2. Finish notes
3. Biomagnification
Classify each member of the food web as autotroph or
heterotroph. Identify the heterotrophs as herbivores,
carnivores, or omnivores. Label as
primary/secondary/tertiary consumer or producer
Herbivore, carnivore,
More biomass at the bottom
-Less mass at upper trophic levels
Biomass Pyramid
Human Impact on food
chains/food webs
• Introduced toxins
– DDT and eagles
• Extermination of a species
– Wolves
Biomagnification and bioaccumulation
• Biomagnification = the increase in
concentration of toxin as it passes through
a food web
– Higher level affected more
• Bioaccumulation = accumulation of toxins
in an organism
– accumulate faster than they are broken down or
– Lower level affected more
Biomagnification of a Toxin in Aquatic
Amount of Toxin in Tissue
Tertiary Consumer
3-76 µg/g ww
(fish eating birds)
Secondary Consumers
1-2 µg/g ww
(large fish)
Primary Consumers
(small fish)
Primary Producers
(algae and aquatic
0.2-1.2 µg/g ww
0.04 µg/g ww
The coyote would be which of the
omnivore, carnivore, or herbivore
Agenda for Thursday Jan 8th
1. Go over HW/review food chains
2. Biomagnification/Bioaccumulation