Changes to ecosystems
Plants
Animals
Decomposers
Matter and Energy in an ecosystem
100
If just one species in a food chain disappears,
A. all of the other organisms will have more food.
B. other organisms will start making their own food.
C. any organisms that depend on that species for food will not be able to meet their needs.
D. no other organisms will be affected.
C. any organisms that depend on that species for food will not be able to meet their needs.
100
The photo below shows the plants in a tropical rainforest ecosystem. Notice that the plants in the understory have especially large leaves. What is the cause of this physical trait? 
- The understory does not get much sunlight, so plant leaves are big to capture more of it.
100
A lion is a(n) _______, an organism that gets food by eating other organisms.
A. plant
B. producer
C. consumer
D. herbivore
C. Consumer
100
What is the role of a decomposer in an ecosystem?
A. capture the energy of sunlight for plants to make food
B. produce oxygen for plants and animals
C. break down dead organisms and their wastes
D. transport nutrients and other materials among organisms
C. break down dead organisms and their wastes
100
Living things obtain ______ from their environment and release ______ back into it.
A. waste, energy
B. waste, matter
C. matter, waste
D. energy, sunlight
C. matter, waste
200
A volcano in Ecuador is erupting, shooting ash into the air. Burning hot gases and bits of rock flow down the side of the mountain. What is the most likely way the eruption will disturb the ecosystem around it?
A. This is a slow change to the ecosystem, but the effects will last for a long time.
B. This is a fast change to the ecosystem and the effects will last for a long time.
C. This is a slow change to the ecosystem but the effects will last a short time.
D. This is a fast change to the ecosystem and the effects will last a short time.
B. This is a fast change to the ecosystem and the effects will last for a long time.
200
What is the order of the four layers in a tropical rainforest, from bottom to top?
A. canopy, forest floor, understory, emergent layer
B. forest floor, understory, canopy, emergent layer
C. forest floor, emergent layer, understory, canopy
D. understory, forest floor, emergent layer, canopy
B. forest floor, understory, canopy, emergent layer
200
When an animal eats more food than it needs right away, its body
A. changes all the food energy into heat.
B. stores the extra food energy as fat to use later.
C. releases all the energy so it does not get fat.
D. converts the energy into sodium to use later.
B. stores the extra food energy as fat to use later.
200
When a decomposer dies, its once-living material becomes waste. These wastes are then
A. converted into energy that can be used.
B. transformed into bacteria that fungi can eat.
C. further decomposed by producers and consumers.
D. released into the air, soil, and water of an ecosystem.
D. released into the air, soil, and water of an ecosystem.
200
Why is the base of an energy pyramid larger than the top?
A. Organisms at the top produce energy for organisms at the bottom.
B. Energy is converted into matter to form larger organisms at the top.
C. Organisms at the top use less energy than organisms at the bottom.
D. Energy is lost as heat at each level so less energy is available at the top
D. Energy is lost as heat at each level so less energy is available at the top
300
Scientists are studying a pond ecosystem. Using this food chain model below, predict what would happen to the turtles following a loss of algae?
A. The turtles will decrease because they eat herons.
B. The turtles will increase because they depend on the dying fish population.
C. The turtles will decrease because they depend on the dying fish population.
D. The turtles will increase because they depend on the dying heron population.
C. The turtles will decrease because they depend on the dying fish population.
300
A(n) ________ is any organism that makes its own food.
A. animal
B. herbivore
C. producer
D. consumer
C. Producer
300
Like other consumers, all of the food energy that humans use once came from the ______.
A. sun
B. soil
C. moon
D. ocean
A. Sun
300
While on a safari in South Africa, you see some vultures pulling meat off the bones of a large, dead mammal. Which of the following observations accurately describes how vultures are different from fungi?
A. Vultures produce juices to digest dead material.
B. Vultures break down tiny food pieces into soil.
C. Fungi leave behind waste while breaking down food.
D. Vultures break down large food pieces into small food pieces.
D. Vultures break down large food pieces into small food pieces.
300
Since humans can eat foods from many different ecosystems, they are
A. part of many food webs.
B. not counted as consumers.
C. part of a simple food chain.
D. considered to be producers.
A. part of many food webs.
400
What kinds of changes take place during succession?
A. Animals move from one ecosystem to another.
B. One or more species die out and no longer exist on Earth.
C. Species slowly replace each other as the landscape changes.
D. Plants stop growing and making food when days get shorter and colder.
C. Species slowly replace each other as the landscape changes.
400
Energy enters most ecosystems as ______
A. sunlight
B. moving air
C. water currents
D. electricity
A. Sunlight
400
This gazelle in running from a lion that is chasing it. Where does the gazelle get the energy it needs to run?
A. directly from sunlight
B. from the food it eats
C. from the wastes it produces
D. from water it drinks
B. From the food it eats
400
Apples that fall to the ground will decompose and some substances from the decomposing apples will return to the apple trees. Which of the following decomposer wastes can apple trees in this forest use again?
A. oxygen released into the water
B. carbon dioxide released into the air
C. methane released into the air
D. nutrients released into the water
B. carbon dioxide released into the air
400
What is a difference between energy and matter?
A. Energy is heat, but matter is cold.
B. Energy flows through an ecosystem, while matter cycles within an ecosystem.
C. Energy and matter are the same.
D. Matter flows through plants to consumers, while energy recycles through the ecosystem.
B. Energy flows through an ecosystem, while matter cycles within an ecosystem.
500
Climate change can cause changes to ecosystems. What can happen to organisms that do not change with their ecosystems?
A. They can disappear from Earth.
B. They can stop the ecosystem from changing.
C. They can form new ecosystems.
D. They can be unaffected by the change.
A. They can disappear from Earth.
500
Plants turn sugar into _______ for storage so they can have energy even when they cannot perform photosynthesis.
A. fat
B. starch
C. protein
D. sodium
B. Starch
500
A monkey gets the energy it needs to climb trees by eating the tree’s leaves. Where did the energy stored in the leaves come from originally?
A. from the soil
B. from the air
C. from sunlight
D. from animal wastes
C. from sunlight
500
Cattle farmers need almost two football fields of grassland to feed just one animal for a year. How much of the energy at the base of the pyramid shown reaches the top (humans), and why?
A. All of it; unlike matter, energy cannot be consumed or destroyed.
B. None of it; cows release all of the grass’s energy as heat, then create their own, new energy.
C. Some of it; both the grass and cattle release some energy as heat before it reaches the human consumer.
D. Most of it; cattle release some energy as heat, the grass does not release energy as heat.
C. Some of it; both the grass and cattle release some energy as heat before it reaches the human consumer.