Of Ecosystem Processes Flashcards
7 cards from real Ecology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Of Ecosystem Processes flashcards as text
Which process converts atmospheric nitrogen into a form usable by plants?
Answer: Nitrogen fixation
Nitrogen fixation, performed by certain bacteria like Rhizobium, converts N₂ gas into ammonia that plants can absorb.
What term describes the total amount of solar energy fixed by producers in an ecosystem per unit time?
Answer: Gross primary productivity
Gross primary productivity (GPP) is the total rate of photosynthetic energy fixation before any respiratory losses.
In the phosphorus cycle, which reservoir holds the largest long-term store of phosphorus?
Answer: Sedimentary rock
Sedimentary rocks are the primary long-term reservoir of phosphorus, which is released slowly through weathering.
What is the fate of most energy that passes through a trophic level?
Answer: It is lost as heat
Roughly 90% of energy at each trophic level is lost as metabolic heat, leaving only ~10% available to the next level.
Which nutrient cycle is considered most tightly coupled to the carbon cycle in ecosystems?
Answer: Nitrogen cycle
The nitrogen cycle is most tightly coupled to carbon cycling because nitrogen limits primary production and is a key component of proteins and chlorophyll.
Which of the following best describes 'ecosystem engineers'?
Answer: Organisms that physically modify habitat structure
Ecosystem engineers like beavers and earthworms physically modify the abiotic environment, creating or maintaining habitats for other species.
What process returns organic nitrogen to inorganic ammonium in the soil?
Answer: Ammonification
Ammonification is carried out by decomposers that break down organic nitrogen in dead matter and waste into ammonium.