AP Environmental Science MIDTERM Review
First Law of Thermodynamics - ANSWER Energy is neither created nor destroyed, but may be
converted from one form to another.
Second Law of Thermodynamics - ANSWER When energy is changed from one form to
another, some useful energy is always degraded into lower quality energy (usually heat).
Hydrologic Cycle Components - ANSWER evaporation, transpiration, runoff, condensation,
precipitation, and infiltration.
Watershed - ANSWER all of the land that drains into a body of water
Aquifer - ANSWER any water-bearing layer in the ground.
La Nina - ANSWER Easterly trade winds and ocean currents pool warm water in the western
Pacific, allowing upwelling of nutrient rich water off the West coast of South America.
Nitrogen Fixation - ANSWER because atmospheric N cannot be used directly by plants, it must
first be converted into ammonia by bacteria.
Ammonification - ANSWER decomposers covert organic waste into ammonia.
Nitrification - ANSWER ammonia is converted to nitrate ions (NO -).
Assimilation - ANSWER inorganic N is converted into organic molecules such as DNA/amino
acids & proteins.
Denitrification - ANSWER bacteria convert ammonia back into N.
, Phosphorus - ANSWER does not exist as a gas; released by weathering of phosphate rocks, it is
a major limiting factor for plant growth. Phosphorus cycle is slow, and not atmospheric.
Photosynthesis - ANSWER plants convert CO2 (atmospheric C) into complex carbohydrates
(glucose C6H12O6).
Aerobic Respiration - ANSWER oxygen consuming producers, consumers & decomposers break
down complex organic compounds & convert carbon back into CO2.
Biotic - ANSWER living components of an ecosystem.
Abiotic - ANSWER nonliving components of an ecosystem
Producer/Autotroph - ANSWER organisms that make their own food—photosynthetic life.
Trophic Levels - ANSWER producers → primary consumer → secondary consumer → tertiary
consumer.
Energy Flow through Food Webs - ANSWER 10% of the usable energy is transferred to the next
trophic level. Reason: usable energy lost as heat (2nd law), not all biomass is digested &
absorbed, predators expend energy to catch prey.
Primary succession - ANSWER development of communities in a lifeless area not previously
inhabited by life (ex. lava).
Secondary succession - ANSWER life progresses where soil remains (ex. clear-cut forest, old
farm).
First Law of Thermodynamics - ANSWER Energy is neither created nor destroyed, but may be
converted from one form to another.
Second Law of Thermodynamics - ANSWER When energy is changed from one form to
another, some useful energy is always degraded into lower quality energy (usually heat).
Hydrologic Cycle Components - ANSWER evaporation, transpiration, runoff, condensation,
precipitation, and infiltration.
Watershed - ANSWER all of the land that drains into a body of water
Aquifer - ANSWER any water-bearing layer in the ground.
La Nina - ANSWER Easterly trade winds and ocean currents pool warm water in the western
Pacific, allowing upwelling of nutrient rich water off the West coast of South America.
Nitrogen Fixation - ANSWER because atmospheric N cannot be used directly by plants, it must
first be converted into ammonia by bacteria.
Ammonification - ANSWER decomposers covert organic waste into ammonia.
Nitrification - ANSWER ammonia is converted to nitrate ions (NO -).
Assimilation - ANSWER inorganic N is converted into organic molecules such as DNA/amino
acids & proteins.
Denitrification - ANSWER bacteria convert ammonia back into N.
, Phosphorus - ANSWER does not exist as a gas; released by weathering of phosphate rocks, it is
a major limiting factor for plant growth. Phosphorus cycle is slow, and not atmospheric.
Photosynthesis - ANSWER plants convert CO2 (atmospheric C) into complex carbohydrates
(glucose C6H12O6).
Aerobic Respiration - ANSWER oxygen consuming producers, consumers & decomposers break
down complex organic compounds & convert carbon back into CO2.
Biotic - ANSWER living components of an ecosystem.
Abiotic - ANSWER nonliving components of an ecosystem
Producer/Autotroph - ANSWER organisms that make their own food—photosynthetic life.
Trophic Levels - ANSWER producers → primary consumer → secondary consumer → tertiary
consumer.
Energy Flow through Food Webs - ANSWER 10% of the usable energy is transferred to the next
trophic level. Reason: usable energy lost as heat (2nd law), not all biomass is digested &
absorbed, predators expend energy to catch prey.
Primary succession - ANSWER development of communities in a lifeless area not previously
inhabited by life (ex. lava).
Secondary succession - ANSWER life progresses where soil remains (ex. clear-cut forest, old
farm).
