Ecosystems Basics
Define Biotic and give an example.
Biotic = living parts of an ecosystem.
What is another name for a producer?
autotroph.
Which organism is always at the bottom of a food chain?
Producers (plants, algae).
Plants take in this gas during photosynthesis.
Carbon dioxide (CO₂).
Name one greenhouse gas.
CO₂, methane, nitrous oxide, or fluorinated gases.
Give an example of an abiotic factor.
sunlight, water, soil, temperature.
What type of consumer eats only plants?
Herbivore
Define food web.
A food web shows multiple interconnected food chains.
What do humans exhale during cellular respiration?
Carbon dioxide (CO₂).
What is the greenhouse effect?
The trapping of heat by greenhouse gases in Earth’s atmosphere.
What is carrying capacity?
The maximum number of organisms an ecosystem can support sustainably.
What is a detritivore? Give an example.
eats dead material (e.g., earthworms, beetles).
What happens to energy as you move up the biomass pyramid?
Energy decreases (only ~10% is passed on).
Which cycle includes evaporation, condensation, and precipitation?
Water cycle
What is one human activity that increases climate change?
Burning fossil fuels, deforestation, farming, transportation.
What are the 4 spheres of Earth’s systems?
Biosphere – all living things
Lithosphere – land, rocks, soil
Hydrosphere – water
Atmosphere – air, gases
Compare autotrophs and heterotrophs.
Autotrophs make their own food; heterotrophs must eat other organisms.
Why is there more biomass at the producer level than at the top consumer level?
Producers are more abundant because energy is lost at each level. Fewer organisms can be supported at higher levels.
How do humans affect the nitrogen cycle?
Fertilizer use, pollution, over-farming.
Give two effects of climate change on ecosystems.
Rising sea levels, extreme weather, melting ice, species extinction, and droughts.
Explain the difference between primary and secondary succession, with an example of each.
Primary succession – occurs where no life/soil existed before (e.g., bare rock after a volcanic eruption). Slow process.
Secondary succession – occurs after a disturbance in an existing ecosystem (e.g., forest regrows after a fire). Faster because soil is already present.
Explain how energy is transferred from producers to tertiary consumers.
Energy flows upward: producers capture sunlight → herbivores → carnivores → top predators. Only ~10% passes to each level.
If producers have 10,000 J of energy, how much is available to secondary consumers?
10% of 10,000 J = 1,000 J for primary consumers, then 100 J for secondary consumers.
Explain how photosynthesis and cellular respiration are connected in the carbon cycle.
Photosynthesis removes CO₂ and makes oxygen; respiration uses oxygen and releases CO₂—together they balance the carbon cycle.
Explain 3 actions humans can take to reduce their ecological footprint.
Use renewable energy, recycle, eat less meat, plant trees, conserve water/energy, and reduce driving.