AP Environmental Science - Topic 1: Ecosystems, Biomes, and Biogeochemical Cycles

Vocabulary flashcards covering ecological hierarchy, species interactions, aquatic and terrestrial biome characteristics, and the processes of the carbon and nitrogen biogeochemical cycles.

Individual

A single organism within an ecosystem, such as one elk.

Population

A group of individuals of the same species living in the same area, such as an elk herd.

Community

All of the living organisms belonging to different species present in a given area.

Ecosystem

All the living (biotic) organisms and nonliving (abiotic) components, such as plants, animals, rocks, soil, water, and air, interacting in a specific area.

Biome

A large regional community of plants and animals defined by its specific climate, primarily based on average yearly temperature and precipitation.

Mutualism

A close and long-term symbiotic interaction between two species in which both organisms benefit ($+/+$).

Commensalism

A symbiotic relationship in which one species benefits while the other is unaffected ($+/0$).

Predation

An interaction in which one organism uses another organism as an energy source ($+/-$).

True Predators

Carnivores that kill and eat their prey for energy.

Herbivores

Organisms that eat plants to obtain energy.

Parasites

Organisms that live on or inside a host organism to gain energy, often without killing the host.

Parasitoids

Organisms that lay eggs inside a host organism, which then hatch so the larvae can consume the host for energy.

Symbiosis

Any close and long-term interaction between two organisms of different species, including mutualism, commensalism, and parasitism.

Resource Partitioning

The practice of different species using a shared limited resource in different ways, places, or times to reduce competition and survive.

Types of Resource Partitioning

The three strategies species use to share limited resources: temporal partitioning (using resources at different times), spatial partitioning (using different areas of a habitat), and morphological partitioning (using different resources based on evolved physical features).

Temporal Partitioning

A form of resource partitioning where competing species utilize the same resource at different times, such as hunting during the night versus during the day.

Spatial Partitioning

A form of resource partitioning where competing species utilize different physical spaces or depths within a shared habitat.

Morphological Partitioning

A form of resource partitioning where competing species evolve distinct physical body features to reduce resource competition.

Lake Zonation

The distinct ecological zones of a freshwater lake defined by light penetration and depth, including the shallow littoral zone with rooted plants, open photic limnetic zone with phytoplankton, deep aphotic profundal zone, and bottom benthic zone.

Littoral Zone

The shallow water area of a freshwater lake near the shore where sunlight reaches the bottom and emergent rooted plants grow.

Limnetic Zone

The open, well-lit surface water layer of a lake where light penetrates to support photosynthesis and phytoplankton, but no rooted plants.

Profundal Zone

The deep layer of a freshwater lake where sunlight cannot penetrate, preventing photosynthesis.

Benthic Zone

The nutrient-rich, murky bottom sediment layer of a body of water inhabited by decomposers and invertebrates.

Wetland

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

Estuary

A coastal aquatic zone where freshwater rivers flow into the ocean, creating a mix of fresh and salt water with high nutrient levels and biological productivity.

Intertidal Zone

The narrow band of ocean coastline located between high tide and low tide, where organisms must adapt to wave action and exposure during low tide.

Ocean Zonation

The vertical and horizontal spatial zones of marine biomes, including the coastal intertidal zone, sunlit photic zone, dark aphotic zone, and bottom benthic zone.

Photic Zone

The upper layer of an aquatic biome that receives sufficient sunlight for photosynthesis.

Aphotic Zone

The deep layer of an aquatic biome that does not receive sunlight, requiring organisms to rely on detritus or chemosynthesis for energy.

Carbon Sink

A carbon reservoir that absorbs and stores more carbon than it releases into the atmosphere, such as oceans, plants, and soil.

Carbon Source

A reservoir or process that releases more carbon into the atmosphere than it absorbs, such as fossil fuel combustion, deforestation, and livestock agriculture.

Photosynthesis and Cellular Respiration Equations

The complementary biochemical pathways cycling carbon between living things: Photosynthesis ($\text{Solar energy} + 6\text{H}_2\text{O} + 6\text{CO}_2 \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$) converts atmospheric carbon to glucose, while Respiration ($\text{Energy} + 6\text{H}_2\text{O} + 6\text{CO}_2 \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$) breaks down glucose to release energy and return carbon dioxide.

Photosynthesis

The chemical process performed by plants, algae, and phytoplankton that converts carbon dioxide ($CO_2$), water ($H_2O$), and solar energy into glucose ($C_6H_{12}O_6$) and oxygen ($O_2$).

Cellular Respiration

The process performed by living organisms that uses oxygen ($O_2$) to break down stored glucose ($C_6H_{12}O_6$) for energy, releasing carbon dioxide ($CO_2$) and water ($H_2O$).

Sedimentation

A slow geological process in the carbon cycle where dissolved calcium carbonate precipitates as sediment and settles on the ocean floor.

Nitrogen Cycle Diagram

The biogeochemical cycle illustrating the movement of nitrogen through various chemical states ($N_2$, $NH_3$, $NH_4^+$ , $NO_2^-$ , $NO_3^-$ , $N_2O$) across reservoirs including the atmosphere, soil bacteria, plants, and animals.

Nitrogen Fixation

The conversion of atmospheric nitrogen gas ($N_2$) into biologically available forms such as ammonia ($NH_3$) or nitrate ($NO_3^-$) via soil bacteria, root nodule symbionts, lightning, or synthetic process.

Nitrification

The two-step biological process by soil bacteria that converts ammonium ($NH_4^+$) into nitrite ($NO_2^-$) and then into nitrate ($NO_3^-$).

Ammonification

The process in which decomposers and soil microbes break down waste and dead biomass, converting organic nitrogen back into ammonium ($NH_4^+$).

Assimilation (Nitrogen Cycle)

The uptake of soil nitrates ($NO_3^-$) or ammonium ($NH_4^+$) by plant roots, or consumption of plants by animals, incorporating nitrogen into biological molecules like proteins and DNA.

Denitrification

The conversion of soil nitrates ($NO_3^-$) into nitrous oxide ($N_2O$) and nitrogen gas ($N_2$) by anaerobic soil bacteria, returning nitrogen to the atmosphere.

Eutrophication

The ecological process where excess nutrient runoff (such as nitrates) stimulates excessive algal growth, causing algal blooms that block sunlight and deplete dissolved oxygen upon bacterial decomposition.