Ecosystem Jobs
What type of organism uses sunlight to make its own food?
Producer
What does a food chain show?
One pathway through which energy moves in an ecosystem.
What is the original source of energy for most ecosystems?
The Sun
Which trophic level contains the greatest amount of energy?
Producers
Does matter flow in one direction or cycle through an ecosystem?
Matter cycles
What type of consumer eats producers such as grass or algae?
Primary consumer
What does a food web show that a food chain does not?
Many connected energy pathways or food chains.
In which direction do the arrows point in a food chain?
From the organism being eaten to the organism receiving the energy.
What happens to the available energy as you move upward through an energy pyramid?
It decreases.
What role do decomposers play in cycling matter?
They break down dead organisms and return nutrients to the environment.
What role do fungi and bacteria usually have in an ecosystem?
Decomposers
In the chain grass → grasshopper → frog → snake, what organism is the secondary consumer?
Frog
In the chain algae → insect → fish → heron, describe the pathway of energy.
Energy moves from the algae to the insect, then to the fish, and finally to the heron.
Producers contain 20,000 units of energy. Using the 10% rule, how much energy reaches the primary consumers?
2,000 units
A fallen leaf decomposes, its nutrients enter the soil, and a plant absorbs them. What does this demonstrate?
The cycling of matter between biotic and abiotic parts.
A rabbit eats grass, and a hawk eats the rabbit. Identify the producer, primary consumer, and secondary consumer.
Grass is the producer, the rabbit is the primary consumer, and the hawk is the secondary consumer.
In a food web, the mouse is eaten by both a snake and a hawk. What does this show about energy pathways?
Energy from the mouse can travel through more than one pathway.
Why can energy move through an ecosystem but not be continuously recycled? Think about was energy is released...
Some energy is released as heat at every step.
Grass contains 50,000 units of energy. Energy moves from grass → grasshopper → frog. How much energy is available to the frog?
500 units
A drought causes grass to decrease. Predict how this may affect rabbits and hawks.
Rabbits may decrease because they have less food, followed by a decrease in hawks because fewer rabbits are available.
Predict what would most likely happen to an ecosystem if its decomposers disappeared.
Dead organisms and waste would accumulate, and nutrients would not be returned to the soil for producers.
A disease causes the mouse population in a food web to decrease. Predict one likely effect on predators that depend on mice.
Their populations may decrease because less food and energy are available.
A student draws an arrow from a fox to a rabbit because the fox eats the rabbit. Explain and correct the student’s mistake.
The arrow should point from the rabbit to the fox because arrows show the direction in which energy moves.
Algae contain 80,000 units of energy. Energy moves from algae → zooplankton → small fish → large fish. How much energy reaches the large fish?
80 units
Your group must explain how our aquaponics system models the cycling of matter. Include the fish, waste, bacteria or decomposers, water, and plants in your explanation.
Fish release waste into the water. Bacteria break down or change the waste into nutrients. The plant roots absorb those nutrients from the water. The water continues moving through the system, allowing matter to be reused instead of disappearing.