Ecological Organization
What is a community in ecology?
A. All individuals of one species in an area
B. All populations of different species living in an area
C. Only the nonliving components of an environment
D. Every ecosystem on Earth combined
B. All populations of different species living in an area
What is the primary energy source for most ecosystems on Earth?
A. Geothermal energy
B. Sunlight
C. Wind
D. Energy stored in rocks
B. Sunlight
What is an autotroph?
A. An organism that consumes only animals
B. An organism that produces organic molecules from inorganic carbon using an energy source
C. An organism that feeds exclusively on dead material
D. An organism that cannot obtain energy from its environment
B. An organism that produces organic molecules from inorganic carbon using an energy source
What is a food chain?
A. A linear sequence showing feeding relationships and energy transfer
B. A diagram showing chromosome organization
C. A cycle in which energy is endlessly reused
D. A graph showing population size over time
A. A linear sequence showing feeding relationships and energy transfer
What is gross primary productivity (GPP)?
A. The total rate at which producers fix energy into organic compounds
B. The amount of energy used only by carnivores
C. The total energy lost through decomposition
D. The amount of biomass consumed by tertiary consumers
A. The total rate at which producers fix energy into organic compounds
What is an ecosystem?
A. A single population of organisms
B. Only the physical environment of a region
C. A biological community together with its abiotic environment
D. A group of organisms belonging to the same species
C. A biological community together with its abiotic environment
What process converts sunlight into chemical energy stored in organic molecules?
A. Cellular respiration
B. Decomposition
C. Photosynthesis
D. Fermentation
C. Photosynthesis
What is a primary consumer?
A. An organism that consumes producers
B. An organism that consumes secondary consumers
C. An organism that produces organic compounds through photosynthesis
D. An organism that consumes only tertiary consumers
A. An organism that consumes producers
What is a food web?
A. A sequence containing only one producer and one consumer
B. A diagram showing only abiotic factors
C. A network of interconnected feeding relationships
D. A representation of genetic relationships among organisms
C. A network of interconnected feeding relationships
What is net primary productivity (NPP)?
A. The total amount of sunlight reaching Earth
B. Gross primary productivity minus energy used in producer respiration
C. The total energy consumed by all heterotrophs
D. The amount of energy released exclusively by decomposers
B. Gross primary productivity minus energy used in producer respiration
Which sequence correctly orders ecological organization from smaller to larger scales?
A. Ecosystem → Organism → Population → Community
B. Organism → Community → Population → Ecosystem
C. Population → Organism → Ecosystem → Community
D. Organism → Population → Community → Ecosystem
D. Organism → Population → Community → Ecosystem
What does the First Law of Thermodynamics state?
A. Energy can be created whenever organisms reproduce
B. Energy is destroyed during cellular respiration
C. Energy cannot be created or destroyed, only transformed
D. All energy transfers occur without losses of usable energy
C. Energy cannot be created or destroyed, only transformed
Which organism is a secondary consumer in the food chain grass → grasshopper → frog → snake?
A. Grass
B. Grasshopper
C. Frog
D. Snake
C. Frog
In a food web, what do arrows generally represent?
A. The direction organisms move through their habitat
B. The direction of energy transfer from food source to consumer
C. The direction of population growth
D. The direction nutrients move exclusively through soil
B. The direction of energy transfer from food source to consumer
Which terrestrial biome generally has among the highest net primary productivity per unit area?
A. Hot desert
B. Arctic tundra
C. Tropical rainforest
D. Polar desert
C. Tropical rainforest
Which example represents an ecosystem rather than only a community?
A. All fish species living in a pond
B. All populations of birds in a forest
C. A pond's organisms, water, sediments, nutrients, and physical conditions
D. All trees growing in a particular forest
C. A pond's organisms, water, sediments, nutrients, and physical conditions
Why is Earth considered an open system with respect to energy?
A. Earth continuously exchanges significant quantities of solid matter with space
B. Energy enters primarily from the Sun and leaves as radiation
C. Earth's energy supply remains completely unchanged
D. Energy cannot cross the boundary between Earth and space
B. Energy enters primarily from the Sun and leaves as radiation
Which statement correctly distinguishes autotrophs and heterotrophs?
A. Autotrophs must consume other organisms, while heterotrophs produce their own organic carbon
B. Autotrophs obtain organic carbon from inorganic sources, while heterotrophs obtain organic carbon from other organisms or organic material
C. Autotrophs exist only in terrestrial ecosystems
D. Heterotrophs cannot perform cellular respiration
B. Autotrophs obtain organic carbon from inorganic sources, while heterotrophs obtain organic carbon from other organisms or organic material
What is the main ecological role of decomposers?
A. Producing all ecosystem energy through sunlight
B. Preventing organic matter from breaking down
C. Converting every consumer into a producer
D. Breaking down dead organic material and releasing nutrients
D. Breaking down dead organic material and releasing nutrients
An ecosystem has a GPP of 2,500 energy units and producers use 900 units through respiration. What is its NPP?
A. 900 units
B. 1,600 units
C. 2,500 units
D. 3,400 units
B. 1,600 units
Why is studying an ecosystem different from studying only a biological community?
A. Ecosystem ecology includes abiotic conditions and processes such as energy flow and nutrient cycling
B. Ecosystem ecology excludes interactions among living organisms
C. Communities contain no populations
D. Ecosystems consist only of abiotic components
A. Ecosystem ecology includes abiotic conditions and processes such as energy flow and nutrient cycling
Why does energy move through ecosystems while nutrients are recycled?
A. Energy is destroyed during consumption, while nutrients are created
B. Energy cycles endlessly between organisms without leaving ecosystems
C. Nutrients cannot move between organisms and the environment
D. Energy is transformed and eventually dissipates as heat, while matter can be reused through biogeochemical cycles
D. Energy is transformed and eventually dissipates as heat, while matter can be reused through biogeochemical cycles
A bear eats berries, insects, and fish. Why might it occupy more than one trophic level in a food web?
A. It changes species depending on its diet
B. It can function only as a primary consumer
C. It produces its own food through photosynthesis
D. It consumes organisms occupying different trophic levels
D. It consumes organisms occupying different trophic levels
In the food chain grass → rabbit → fox → eagle, what is the eagle's trophic level?
A. Primary consumer, level 2
B. Secondary consumer, level 3
C. Tertiary consumer, level 4
D. Producer, level 1
C. Tertiary consumer, level 4
Producers store 20,000 energy units. Assuming 10% ecological efficiency at each transfer, approximately how much production reaches tertiary consumers?
A. 2 units
B. 20 units
C. 200 units
D. 2,000 units
B. 20 units