AP Environmental Science Unit 1: Ecosystems Vocabulary

Comprehensive vocabulary flashcards generated from the AP Environmental Science Unit 1 (Ecosystems) lecture slides.

Ecosystem

All the living (biotic) and nonliving (abiotic) things interacting in a given area, including plants, animals, rocks, soil, water, and air.

Biome

A large region characterized by distinct plant and animal communities adapted to its specific climate, determined primarily by annual average temperature and precipitation.

Mutualism

A symbiotic relationship between two organisms of different species in which both organisms benefit ($+$/$+$).

Commensalism

A symbiotic relationship between two organisms where one organism benefits while the other is neither helped nor harmed ($+$/$0$).

Parasitism

A relationship where one organism (the parasite) benefits at the expense of another organism (the host) by living on or in it for energy, usually without immediately killing it ($+$/ $-$).

Parasitoid

An organism that lays its eggs inside a host organism; when the eggs hatch, the larvae consume the host for energy, ultimately killing it.

Competitive Exclusion Principle

The ecological principle stating that two species competing for the exact same limited resource cannot coexist indefinitely in the same region.

Resource Partitioning

The process where different species use a shared resource in different ways, places, or at different times to reduce competition and allow coexistence.

Temporal Partitioning

A method of resource partitioning in which competing species utilize a shared resource at different times of the day or year.

Spatial Partitioning

A method of resource partitioning in which competing species utilize different physical areas or sub-habitats within a shared area.

Morphological Partitioning

A method of resource partitioning where competing species evolve distinct physical body features to utilize different resources.

Niche

A species' specific role and set of interactions within its ecosystem, encompassing its use of biotic organisms and abiotic factors.

Fundamental Niche

The theoretical range of environmental conditions and resources a species could potentially occupy and use in the absence of competition.

Realized Niche

The actual range of environmental conditions and resources a species occupies and uses as a result of competition and other ecological interactions.

Tundra

A cold, high-latitude ($60^\bullet+$) biome characterized by permafrost, low nutrient availability, frozen soils, and low-growing vegetation.

Taiga (Boreal Forest)

A cold, high-latitude biome composed primarily of coniferous trees, featuring nutrient-poor soil due to low decomposition rates.

Littoral Zone

The shallow, near-shore aquatic zone of a lake where sunlight reaches the sediment and rooted emergent plants can grow.

Limnetic Zone

The open, well-lit upper layer of a lake where sunlight supports photosynthetic organisms like phytoplankton, but rooted plants cannot grow.

Profundal Zone

The deep zone of a lake located below the range of effective light penetration, where photosynthesis cannot take place.

Benthic Zone

The murky bottom sediment layer of an aquatic biome, inhabited by decomposers and invertebrate organisms.

Wetland

An ecosystem with soil submerged or saturated in water for at least part of the year, shallow enough to support rooted emergent plants.

Estuary

A highly productive coastal aquatic biome where freshwater from rivers empties into and mixes with saltwater from the ocean.

Mangrove Swamps

Tropical coastal estuary ecosystems characterized by specialized mangrove trees with long stilt roots that stabilize shorelines and shelter aquatic species.

Intertidal Zone

The narrow coastal strip between high and low tide lines, where organisms must adapt to wave action and exposure during low tide.

Carbon Sink

An ecological reservoir that absorbs and holds more carbon than it releases, such as oceans, plants, or soil.

Carbon Source

An ecological reservoir or human activity that releases more carbon into the atmosphere than it absorbs, such as fossil fuel combustion or deforestation.

Photosynthesis

The biological process performed by plants, algae, and phytoplankton that removes atmospheric $CO_2$ and converts it into biological glucose using solar energy.

Cellular Respiration

The metabolic process in living organisms that utilizes $O_2$ to break down glucose for energy, returning $CO_2$ back to the atmosphere.

Nitrogen Fixation

The conversion of inert atmospheric nitrogen gas ($N_2$) into biologically available forms like ammonia ($NH_3$) or nitrate ($NO_3^-$) by bacteria or synthetic processes.

Nitrification

The two-step biological process in soil where bacteria convert ammonium ($NH_4^+$) into nitrite ($NO_2^-$) and then into nitrate ($NO_3^-$).

Ammonification

The process performed by soil decomposers and microbes that breaks down animal waste and dead biomass, returning nitrogen to the soil as ammonia ($NH_3$).

Assimilation

The absorption and incorporation of inorganic nutrients (like nitrates or phosphates) into plant tissues, which are then passed to animals via consumption.

Denitrification

The conversion of soil nitrate ($NO_3^-$) into nitrous oxide ($N_2O$) gas by specialized bacteria, returning nitrogen to the atmosphere.

Eutrophication

An ecological process triggered by excess nitrogen and phosphorus runoff, leading to dense algae blooms, oxygen depletion, and aquatic organism mortality.

Transpiration

The movement of groundwater from plant roots up through leaves, where it evaporates as water vapor into the atmosphere via stomata.

Evapotranspiration

The total combined amount of water vapor entering the atmosphere from both surface evaporation and plant transpiration.

Gross Primary Productivity (GPP)

The total amount of solar energy that producers in a given area capture and convert into biological energy (glucose) via photosynthesis over time.

Net Primary Productivity (NPP)

The rate of energy stored as organic biomass by producers after accounting for energy lost to cellular respiration ($NPP = GPP - RL$).

10% Rule

The rule approximating that only about 10\text{--}15\text{\textpercent} (10\text{\textpercent}) of usable energy is transferred from one trophic level to the next, while 90\text{\textpercent} is lost as heat or used for respiration.

Trophic Cascade

An ecological chain reaction that occurs when the population size of a top predator is altered, cascading through successive lower trophic levels.

Food Web

A complex network model composed of interconnected food chains depicting the multidirectional pathways of energy and nutrient flow in an ecosystem.