All flashcards
Flashcard 1: Which evidence best supports nitrogen fixation in legume root nodules?
Answer: Higher plant nitrogen content when nodules are present. Bacteria in nodules provide nitrogen, increasing plant growth.
Flashcard 2: What nitrogen-cycle process converts organic nitrogen in dead matter into ammonium?
Answer: Ammonification (decomposition). Organic nitrogen is broken down back to inorganic forms.
Flashcard 3: Which evidence best supports increased carbon sequestration in a reforested area?
Answer: Rising tree biomass and increasing soil organic carbon. More carbon stored in both above and below-ground pools.
Flashcard 4: Which term describes the movement of nutrients from one trophic level to the next?
Answer: Consumption (trophic transfer of matter). Nutrients pass from prey to predator through feeding.
Flashcard 5: Which term describes the conversion of organic matter into inorganic nutrients by microbes?
Answer: Mineralization. Microbes break down complex organic compounds to simple ions.
Flashcard 6: Which evidence best supports mineralization in forest litter over time?
Answer: Organic nitrogen decreases while inorganic ammonium/nitrate increases. Decomposition converts organic nitrogen to inorganic forms.
Flashcard 7: Which option is the most direct evidence that carbon cycles between plants and animals?
Answer: Plants fix CO2; animals release CO2 during respiration. Shows carbon moving between autotrophs and heterotrophs.
Flashcard 8: What is the term for nutrients entering an ecosystem from outside sources?
Answer: Nutrient input. External sources add nutrients to the ecosystem.
Flashcard 9: Which evidence best supports that soil microbes drive nutrient cycling?
Answer: Sterilized soil shows reduced nitrate formation and plant growth. Killing microbes disrupts the biological processes they perform.
Flashcard 10: Which statement is supported if decomposers are removed and detritus accumulates?
Answer: Nutrient recycling slows due to reduced decomposition. Without decomposers, organic matter accumulates instead of recycling.
Flashcard 11: What is a trophic level in the context of matter cycling?
Answer: A feeding position where matter is transferred by consumption. Each feeding level in a food chain or web.
Flashcard 12: What is the term for nutrients leaving an ecosystem via water or harvesting?
Answer: Nutrient output (loss). Nutrients exit the ecosystem through various pathways.
Flashcard 13: Which evidence best supports nutrient transfer up a food chain?
Answer: Higher tissue nitrogen or carbon in consumers after feeding. Consumption transfers nutrients from food into consumer tissues.
Flashcard 14: Which term describes the movement of nutrients from one trophic level to the next?
Answer: Consumption (trophic transfer of matter). Nutrients pass from prey to predator through feeding.
Flashcard 15: Which evidence best supports increased carbon sequestration in a reforested area?
Answer: Rising tree biomass and increasing soil organic carbon. More carbon stored in both above and below-ground pools.
Flashcard 16: Which term describes carbon stored long-term in wood, soils, or sediments?
Answer: Carbon sequestration. Carbon is removed from atmosphere and stored long-term.
Flashcard 17: Which measurement is direct evidence that carbon is stored in biomass?
Answer: Increased dry mass or increased percent carbon in tissues. Direct measurement shows carbon accumulated in living tissues.
Flashcard 18: Which term describes the total mass of living organic matter in an ecosystem?
Answer: Biomass. Total weight of all living organisms in an area.
Flashcard 19: Which evidence best supports phosphate limitation in a lake ecosystem?
Answer: Algal growth increases after phosphate is added. Phosphate addition stimulates growth when it's the limiting nutrient.
Flashcard 20: Which evidence pattern best supports eutrophication in a pond?
Answer: High nitrate/phosphate, algal bloom, then low dissolved O2. Classic sequence shows nutrient input leading to oxygen loss.
Flashcard 21: What is eutrophication in terms of nutrient cycling evidence?
Answer: Nutrient enrichment causing algal blooms and oxygen decline. Excess nutrients cause algal overgrowth and oxygen depletion.
Flashcard 22: Which evidence best supports increased runoff after deforestation?
Answer: Greater stream discharge and reduced infiltration after tree removal. Trees normally absorb water; removal increases surface flow.
Flashcard 23: What is the term for water soaking into the ground from the surface?
Answer: Infiltration. Water penetrates soil surface and moves underground.
Flashcard 24: Which evidence best supports transpiration increasing on a hot, dry day?
Answer: Higher water loss rate from leaves or increased local humidity. Heat increases evaporation rate from plant surfaces.
Flashcard 25: Which water-cycle process moves water from leaves to the atmosphere?
Answer: Transpiration. Plants release water vapor through leaf pores (stomata).
Flashcard 26: Which process releases phosphate from rocks into soil and water?
Answer: Weathering and erosion. Physical breakdown of rocks releases phosphate into ecosystems.
Flashcard 27: Which phosphorus-cycle feature is correct: does it have a major atmospheric gas phase?
Answer: No, phosphorus lacks a major atmospheric gas phase. Phosphorus cycles mainly through rocks, soil, and water.
Flashcard 28: Which evidence best supports denitrification in waterlogged soils?
Answer: Nitrate decreases and N2 (or N2O) emissions increase. Conversion of nitrate to gaseous forms in anaerobic conditions.
Flashcard 29: Which water-cycle process is indicated by water vapor turning into liquid droplets?
Answer: Condensation. Water vapor loses energy and forms liquid droplets.
Flashcard 30: Which option best supports that phosphorus can limit productivity in freshwater ecosystems?
Answer: Adding phosphate increases primary production more than controls. Experimental evidence shows phosphorus controls growth rate.