Ammonification
The process in which decomposers convert organic nitrogen compounds into ammonia
Commensalism
A symbiotic relationship between two species where one benefits, and the other is neither helped nor harmed
Competition
The interaction between organisms in which individuals of the same or different species strive for the same resources
Consumer
An organism that obtains energy by feeding on other organisms or organic matter
Gross Primary Productivity (GPP)
The total amount of solar energy that producers in an ecosystem capture via photosynthesis over a given period
Limiting Factor
A factor that restricts the growth, abundance, or distribution of a population in an ecosystem
Mutualism
A symbiotic relationship between two species in which both benefit
Net Primary Productivity (NPP)
The amount of energy captured by producers in an ecosystem minus the energy they expend in respiration
Nitrification
The conversion of ammonia to nitrite and then to nitrate by nitrifying bacteria
Nitrogen Fixation
The process by which nitrogen gas (N2) from the atmosphere is converted into ammonia (NH3) by nitrogen-fixing bacteria
Parasitism
A symbiotic relationship between two species in which one benefits at the expense of the other
Predation
The act of one organism (predator) capturing and consuming another organism (prey)
Producer
An organism that produces its own food through photosynthesis or chemosynthesis, forming the base of the food chain
Respiration
The process by which organisms release energy from organic molecules, typically involving the consumption of oxygen and the production of carbon dioxide
Symbiosis
A close and long-term interaction between two different species
Ten Percent Rule
A rule stating that, on average, only about 10% of the energy available at one trophic level is transferred to the next trophic level
Trophic Level
Each step in a food chain or food web, representing a feeding level
Bottleneck
A sharp reduction in the size of a population due to environmental events or human activities, leading to a loss of genetic diversity
Ecosystem Diversity
The variety of ecosystems in a given area, including different types of communities, habitats, and landscapes
Ecosystem Services
The benefits that ecosystems provide to humans, including provisioning, regulating, supporting, and cultural services
Endemic Species
Species that are native and restricted to a particular geographic area
Founder Effect
The reduced genetic diversity that results when a small subset of a population establishes a new population
Generalist
A species with a broad ecological niche, able to thrive in a variety of environmental conditions
Genetic Diversity
The variety of genes within a population or species
Genetic Drift
Changes in the frequency of a gene variant in a population due to random events
Indicator Species
Species whose presence, absence, or abundance provides information about environmental conditions
Invasive Species
Non-native species that, when introduced to a new area, outcompete or disrupt native species and ecosystems
Island Biogeography
The study of the ecological relationships and distribution of species on islands
Keystone Species
A species that has a disproportionately large impact on its ecosystem relative to its abundance
Pioneer Species
The first species to colonize a newly disturbed or barren area in the process of primary succession
Primary Succession
The process of ecological succession that occurs in an area devoid of life and soil, typically after a major disturbance
Resource Partitioning
The division of resources among species to minimize competition and allow coexistence
Secondary Succession
The process of ecological succession that occurs in an area where an existing community has been disturbed but soil remains
Specialist
A species with a narrow ecological niche, typically adapted to a specific set of environmental conditions
Species Diversity
The variety of species in a particular area
Zone of Tolerance
The range of environmental conditions within which an organism or species can survive and reproduce
Age Structure Diagram
A graphical representation of the distribution of age groups in a population
Biotic Potential
The maximum reproductive capacity of a population under optimal environmental conditions
Carrying Capacity
The maximum population size that an environment can support sustainably
Demographic Transition
The shift from high birth and death rates to low birth and death rates in a population
K-Selected Species
Species that have few offspring but invest a lot of time and resources in their survival
Population Momentum
The tendency for a population to continue growing even after replacement-level fertility has been reached
R-Selected Species
Species that produce many offspring but invest little parental care in their survival
Replacement-Level Fertility
The number of children a couple must have to replace themselves in a population
Resilience
The ability of a system to recover from disturbance and return to its original state
Resistance
The ability of a system to remain unchanged in the face of external influences
Rule of 70
A formula used to estimate the doubling time of a population, calculated by dividing 70 by the growth rate
Survivorship Curve
A graph showing the number or proportion of individuals surviving to each age for a given species or group
Atmosphere
The layer of gases surrounding the Earth
Convection Cell
A large-scale pattern of atmospheric circulation in which warm air rises and cool air sinks
Coriolis Effect
The deflection of moving air or water caused by the Earth's rotation
Erosion
The process by which soil and rock are removed from the Earth's surface and transported to another location
El Niño
A climate pattern characterized by warm ocean temperatures in the equatorial Pacific, leading to global weather changes
Insolation
The incoming solar radiation received by the Earth
Permeability
The ability of a material to transmit fluids, such as water
Precipitation
Any form of water, liquid or solid, that falls from the atmosphere to the Earth's surface
Rain Shadow Effect
A dry area on the leeward side of a mountain range, caused by the moist air being lifted and losing moisture on the windward side
Runoff
Water that flows over the land surface and enters rivers and streams
Soil Horizon
A layer of soil with distinct physical and chemical properties
Soil Profile
A vertical section of soil layers, from the surface to the bedrock
Tectonic Plates
Large pieces of the Earth's lithosphere that move and interact with each other
Volcanism
The process by which magma from the Earth's interior reaches the surface
Watershed
An area of land that drains into a particular river, lake, or other body of water
Weathering
The breakdown of rocks into smaller particles through physical, chemical, or biological processes
Acid Mine Drainage
The outflow of acidic water from metal mines or coal mines
Aquaculture
The farming of aquatic organisms, such as fish and shellfish, in controlled environments
Aquifer
An underground layer of permeable rock or sediment that contains water
CAFO (Concentrated Animal Feeding Operation)
A large-scale industrial facility where animals are raised in confinement
Clear Cutting
The removal of all trees from an area, leaving it devoid of forest cover
Drip Irrigation
A method of watering crops by delivering water directly to the roots through a network of pipes, tubes, and emitters
Deforestation
The large-scale removal or destruction of forests, often for the purpose of converting the land to agriculture or development
Fertilizer
Substances added to soil or plants to provide essential nutrients for growth
GMO
An organism whose genetic material has been altered using genetic engineering techniques
Green Revolution
The period of increased agricultural productivity in the mid-20th century, associated with the use of modern technology and crop varieties
Irrigation
The artificial application of water to land to assist in the growth of crops
Overgrazing
The excessive consumption of vegetation by animals, leading to the degradation of ecosystems
Selective Cutting
The practice of harvesting only certain trees from a forest
Slash and Burn Agriculture
A method of farming in which vegetation is cut down and burned before new crops are planted
Tiling
The installation of underground drainage pipes to remove excess water from soil
Tragedy of the Commons
A concept that describes the depletion or degradation of a shared resource (the commons) when individuals, acting in their self-interest, exploit the resource without considering the long-term consequences. This often leads to overuse and the degradation of the resource, as each individual seeks to maximize their own benefit.
Waterlogging
The saturation of soil with water to the point where it hinders plant growth by reducing oxygen availability in the root zone. Waterlogging can occur when soil is excessively irrigated or in areas with poor drainage.
Dependent Variable
In an experiment or study, the variable that is being measured or observed. It is the outcome or response that researchers are trying to understand or predict. It depends on the independent variable.
Independent Variable
In an experiment or study, the variable that is intentionally manipulated or changed by the researcher. It is the variable believed to have an effect on the dependent variable, allowing researchers to observe and measure the impact of changes.
Ecological Footprint
A measure of human impact on the environment, specifically the amount of biologically productive land and water required to provide the resources a person or population consumes and to absorb the waste they generate. It is expressed in global hectares (gha) or acres. The ecological footprint considers factors such as food consumption, energy use, transportation, and waste generation to assess environmental sustainability.