A soil fungus grows through fallen leaves in a city park and releases nutrients into the soil. What role does it play?

Native grasses on a restored prairie use sunlight, water, and carbon dioxide to build biomass. How should the grasses be classified?

A rabbit feeds on clover growing beside an agricultural field. What ecosystem role does the rabbit have?

An earthworm eats decaying vegetable scraps in a community compost pile. How is the earthworm best classified?

Algae bloom in a nutrient-enriched pond and use sunlight to make sugars. What role do the algae occupy?

After roadkill appears near a highway, a vulture feeds on the carcass. What role does the vulture play?

Bacteria in a wastewater treatment system break down organic wastes in the effluent. What ecosystem role do these bacteria perform?

A deer eats newly planted tree seedlings along a forest edge. What role does the deer occupy in that food chain?

Corn planted for ethanol production captures solar energy and stores it as sugars. What role does the corn play in the field ecosystem?

Termites feed on a fallen log, chewing the wood into fragments, while microbes living in their gut chemically digest the cellulose. How are the termites themselves best classified?

A dairy cow obtains energy by eating pasture grass. How is the cow classified in the pasture ecosystem?

Cyanobacteria in a reservoir use sunlight to turn carbon dioxide into organic matter. What role do they have?

A rooftop garden's tomato plant uses light energy to make glucose from carbon dioxide and water. How is it classified by energy acquisition?

A feedlot steer gains chemical energy by digesting corn silage. How is it classified by energy acquisition?

At a deep-sea vent, sulfur-oxidizing bacteria use energy from hydrogen sulfide and carbon dioxide to build sugars. How are they classified?

A fungus on discarded bread absorbs nutrients from the bread after secreting digestive enzymes. How does it obtain energy?

Fertilizer runoff causes rapid growth of duckweed, which uses sunlight to form new biomass. What energy strategy explains the duckweed's growth?

Coral reef algae use sunlight to produce sugars, some of which can support their coral hosts. How should the algae be classified?

A person eats beans harvested from a farm. Is the person an autotroph or a heterotroph?

Nitrifying bacteria in a treatment plant oxidize ammonia for energy and fix carbon dioxide into organic molecules. What type are they?

A maple seedling shaded by a building still makes sugars from carbon dioxide when light reaches its leaves. Which classification remains correct?

A mushroom farm grows fungi on straw, and the fungi absorb carbon and energy from the straw. What classification fits the fungi?

In a field food chain, grass is eaten by a grasshopper, which is eaten by a frog, which is eaten by a snake, which is eaten by a hawk. What trophic level is the hawk?

Zooplankton feed on phytoplankton, anchovies eat zooplankton, and tuna eat anchovies. What trophic level is the tuna?

A wolf eats deer that browse willow shoots near a stream. What trophic level does the wolf occupy?

When a person eats corn directly rather than feeding it to livestock first, what trophic level does the person occupy?

A ladybug eats aphids that feed on bean plants in a garden. What trophic level is the ladybug?

An owl eats a mouse that eats seeds spilled from a grain truck. What trophic level is the owl?

In a seagrass food chain, a snail eats seagrass, a triggerfish eats the snail, and a shark eats the triggerfish. What trophic level is the shark?

A fox eats grasshoppers feeding on grass in an urban meadow. How should the fox be placed in this food chain?

A person eats salmon that ate zooplankton, and the zooplankton ate algae. What trophic level does the person occupy?

An eagle eats fish that eat insect larvae grazing on algae. What trophic level is the eagle?

A soil sterilant removes decomposers from a woodland while plants and animals remain. What is the most likely result over the following seasons?

A construction project removes most native grasses from a prairie. What change is most likely to occur first in the local food web?

A pesticide eliminates most zooplankton from a lake. Because zooplankton graze phytoplankton, what is a likely short-term result?

In a forest preserve, wolves are extirpated while deer remain abundant. What is a likely effect on young tree seedlings?

Fungicides greatly reduce decomposer fungi in a leaf-litter layer. What change best indicates reduced nutrient cycling?

Heavy turbidity blocks light in a reservoir and sharply reduces phytoplankton production. Which group faces the most direct loss of food energy?

Sea otters are removed from a kelp forest food web where they prey on sea urchins. What change is most likely?

An oil spill causes a collapse in phytoplankton primary productivity near the water surface. What is the most likely food-web consequence?