CSS - PMS - CCE - PCS - General Science
Ecosystem
What is ecological succession?
A. Instant extinction of all species
B. A gradual change in community composition over time
C. Movement of one animal
D. Daily weather change
Correct Answer: B
Succession describes directional ecological change following formation or disturbance of habitats.
CSS - PMS - CCE - PCS - General Science
Ecosystem
Which process returns carbon dioxide to the atmosphere from living organisms?
A. Transpiration only
B. Respiration
C. Nitrogen fixation
D. Photosynthesis only
Correct Answer: B
Cellular respiration releases CO2 as organic molecules are oxidized.
CSS - PMS - CCE - PCS - General Science
Ecosystem
What generally happens to available energy as one moves to higher trophic levels?
A. It increases without limit
B. It decreases
C. It remains exactly constant
D. It becomes matter only
Correct Answer: B
Energy is lost as heat and through metabolism at each trophic transfer.
CSS - PMS - CCE - PCS - General Science
Ecosystem
What is an ecological niche?
A. Only its body size
B. The functional role and resource use of a species in its environment
C. Only its color
D. Only its geographic address
Correct Answer: B
A niche includes how a species uses resources and interacts with biotic and abiotic factors.
CSS - PMS - CCE - PCS - General Science
Ecosystem
What is a habitat?
A. The physical place where an organism lives
B. The total number of species on Earth
C. The organism's genetic code
D. A food chain only
Correct Answer: A
Habitat describes the environment in which an organism lives.
CSS - PMS - CCE - PCS - General Science
Ecosystem
What is the role of decomposers?
A. Break down dead organic matter and recycle nutrients
B. Prevent all predation
C. Create sunlight
D. Make atmospheric oxygen disappear
Correct Answer: A
Decomposers such as fungi and bacteria return nutrients to ecosystems.
CSS - PMS - CCE - PCS - General Science
Ecosystem
What are producers in an ecosystem?
A. Parasites only
B. Organisms that only decompose dead matter
C. Animals that eat plants only
D. Organisms that make organic food from inorganic materials, usually by photosynthesis
Correct Answer: D
Primary producers convert light or chemical energy into organic matter.
CSS - PMS - CCE - PCS - General Science
Ecosystem
Which is an abiotic component of an ecosystem?
A. Plants
B. Fungi
C. Bacteria
D. Temperature
Correct Answer: D
Abiotic components are nonliving physical or chemical factors.
CSS - PMS - CCE - PCS - General Science
Ecosystem
Which is a biotic component of an ecosystem?
A. Sunlight
B. Plants
C. Water
D. Temperature
Correct Answer: B
Biotic components are living organisms.
CSS - PMS - CCE - PCS - General Science
Ecosystem
What is an ecosystem?
A. A community of organisms interacting with each other and with the nonliving environment
B. Only soil and rocks
C. A single organism
D. Only the animals in a forest
Correct Answer: A
An ecosystem includes biotic communities and abiotic environmental components.