AP Environmental Science Semester 1 Study Guide

This set of flashcards covers key vocabulary and concepts from the AP Environmental Science Semester 1 lecture notes.

Independent Variable

A factor that is changed or controlled in an experiment to test its effects on the dependent variable.

Dependent Variable

The outcome factor that is measured in response to changes in the independent variable.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

GPP (Gross Primary Productivity)

The total amount of energy captured by photosynthesis in a given area and time.

NPP (Net Primary Productivity)

The rate of energy storage by plants in the form of organic matter after accounting for energy lost through respiration.

Biogeochemical Cycle

The movement of elements and compounds through biological, geological, and chemical processes in ecosystems.

Succession

The process by which ecosystems change and develop over time, typically following a disturbance.

Food Web

A complex network of interrelated food chains in an ecosystem.

Keystone Species

A species that has a disproportionately large impact on its environment relative to its abundance.

Ecosystem Services

The benefits that humans obtain from ecosystems, such as clean water, pollination, and climate regulation.

Limiting Factor

A resource that is in short supply and restricts the growth of a population.

Abiotic Factors

Non-living physical and chemical elements in the ecosystem, such as temperature, water, and nutrients.

Primary Succession

The establishment of a biological community in an area that was previously uninhabited or lacking soil.

Secondary Succession

The process of regrowth and redevelopment of an ecosystem after a disturbance that does not destroy the soil.

Trophic Levels

The levels of a food chain which represents the flow of energy; includes producers, consumers, and decomposers.

Carrying Capacity

The maximum number of individuals of a species that an environment can sustainably support.

r-selected Species

Species that produce many offspring but invest little in each one, often found in unstable environments.

K-selected Species

Species that produce fewer offspring but invest significant resources in raising each one, usually in stable environments.

Detritivores

Organisms that feed on dead organic matter and help recycle nutrients back into the ecosystem.

Invasive Species

Non-native species that spread rapidly in a new environment and disrupt the balance of the ecosystem.

Ecosystem Diversity

The variety of ecosystems within a particular area, affecting the overall health and resilience of our planet.

Abiotic Fixation

The conversion of atmospheric N{2} into nitrates (NO{3}) in the soil, catalyzed by lightning.

Biotic Fixation

The conversion of atmospheric N{2} into ammonium (NH{4}) in the soil by bacteria, such as those found in legume roots.

Nitrification

A two-step process where soil bacteria convert ammonium (NH{4}) into nitrites (NO{2}) and then into nitrates (NO_{3}).

Denitrification

The process in which soil bacteria convert nitrates (NO{3}) and nitrites (NO{2}) back into atmospheric nitrogen gas (N_{2}).

Assimilation (Nitrogen)

The uptake of soil nitrogen (NH{4}, NO{3}, or NO_{2}) by plants to build organic nitrogen in plant tissues.

Ammonification

The process where decomposers (bacteria, fungi, insects) convert organic nitrogen from dead organisms or waste into ammonium (NH_{4}).

Leaching

The movement of nitrogen compounds (NH{4}, NO{3}, or NO_{2}) from the soil into groundwater or surface waters via infiltrating water.

Weathering / Erosion (Phosphorus)

The breakdown of phosphorus in rocks by rain and wind to produce phosphate (PO_{4}) in water and soil.

Acid Precipitation (Sulfur)

The process where atmospheric sulfate (SO_{4}), often from combustion, returns to soil and surface waters through rain.