Wednesday October 7th

In Notebook:Identify: a primary producer, primary

consumer, and secondary consumer.

Today’s Learning Targets

Agenda:

1.Formative Assessment

2.Ecological Pyramids

3.Bioaccumulation/Biomagnification

Food Web vs. Food Chain

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Interpret these pyramids. Do you think these pyramids depend on each other or are they independent?

What trends do we see in common for all these pyramids?

Biomass Pyramid

• The total mass of living matter at each trophic level

• Why is there more biomass in the lower trophic levels and less biomass in the higher trophic levels?

Energy Pyramid

• Shows trophic (feeding) levels and energy available to each level– 10% energy gets passed to

each level – 90% energy lost

(living/respiration)

Example:Fill in the levels of the food chain with the energy passed on.

10,000 J of energy

Example: Fill in the levels of the food chain with the energy passed on.

750,000 J of energy

While transferring energy what else can be transferred??

. . .

Bioaccumulation vs. Biomagnification

• Bioaccumulation = the accumulation of a contaminant or toxin in or on an organism from all sources (e.g., food, water, air)– accumulate in living things and stored faster

than they are broken down or excreted• Biomagnification = the increase in

concentration of toxin as it passes through each level of the food web

What affect does _____ have on

biomagnification?Life SpanTrophic Level

Lactation

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Example:• DDT: a pesticide used for mosquito and pest control

• In animals DDT is metabolized to DDE, which is stored in fatty tissues and is insoluble in water.

• Banned in U.S.A. in 1972

• Damage from DDT: reproductive failure (birds have thinning eggshells), immune system problems, nervous system damage, death

Biomagnification of a DDE in Aquatic Environment

Tertiary Consumer 3-76 µg/g ww

(fish eating birds)

Level Amount of DDE in Tissue

Secondary Consumers 1-2 µg/g ww

(large fish)

Primary Consumers

(small fish)0.2-1.2 µg/g ww

Primary Producers

(algae and aquatic plants)0.04 µg/g ww

What does this mean for us?

Watch where your food comes from!

Practice!• Use the following information to construct a food web in a meadow ecosystem:

• Red foxes feed on raccoons, crayfishes, grasshoppers, red clover, meadow voles, and gray squirrels

• Red clover is eaten by grasshoppers, muskrats, red foxed, and meadow voles

• Meadow voles, gray squirrels, and raccoons all eat parts of the white oak tree

• Crayfishes feed on green algae and detritus, and they are eaten by muskrats and red foxes.

• Raccoons feed on muskrats, meadow voles, gray squirrels, and white oak trees.

• Identify all of the herbivores, carnivores, omnivores, and detritivores in the food web.

• Describe how the muskrats would be affected if disease kills the white oak trees.