APES Vocabulary

Intraspecific Competition

Competition within the same species.

Interspecific Competition

Competition between different species.

Resource Partitioning

Species evolve to use different parts of the same resource (e.g., birds using different parts of a tree).

Competitive Exclusion

One species outcompetes the other, leading to the local extinction of the weaker competitor.

Nitrogen Fixation

The process by which the triple bond between two nitrogen atoms is broken, in order to create DNA, RNA, or other vital proteins for life.

Nitrification

Conversion of ammonium into nitrite and then into nitrate.

Assimilation

The process by which organisms take in inorganic compounds (nitrogen, phosphorus) and use it to make organic compounds. (There is no gas stage in the phosphorus cycle)

Mineralization

The transformation of nitrogen back into inorganic compounds such as ammonium when organisms die and decompose.

Cellular Respiration

A process performed by producers and consumers; stored chemical energy is converted to ATP.

Inefficiency of Primary Productivity

Only about 1% of what is available to producers is converted through photosynthesis. Furthermore, only about 0.25% of all solar radiation that hits the planet becomes chemical energy.

First Law of Thermodynamics

Energy cannot be created or destroyed, rather it changes forms.

Second Law of Thermodynamics

The state of entropy of the entire universe, as an isolated system, will always increase over time.

Feedback Loops

A positive feedback loop is destabilizing, while a negative feedback loop is stabilizing.

Species Richness

The number of different species present in a given area or community.

Species Evenness

A measure of how evenly individuals are distributed among different species in a community or ecosystem.

Provisioning Service

Products of ecosystems that humans can use directly. (ex. lumber, food crops, furs, medicinal plants)

Regulating Service

The benefits ecosystems provide by natural processes that moderate or control environmental conditions, helping to maintain balance and stabilize the biosphere. Includes water purification, pollination, erosion control, etc.

Supporting Service

Things that support humans that would be very costly for humans to generate themselves. They enable the environment to function, serving as the biological base for regulating, provisioning, and cultural services, often providing only indirect, long-term benefits to humans.

Cultural Service

Refers to the non-material benefits that people derive from ecosystems in the form of cultural, spiritual, or recreational experiences.

Allopatric Speciation

Occurs when populations of a species become geographically isolated from each other, preventing gene flow between them.

Sympatric Speciation

Occurs when new species arise within the same geographical area, without physical isolation.

Genetic Drift

The change in the frequency of an existing genetic allele in a population due to chance.

Primary Succession in Aquatic Ecosystems

Occurs through the formation of substrate (sand, mud, rock), and the addition of pioneer species (algae, cyanobacteria).

Effects of Succession

Succession initially increases species richness, total biomass, and productivity. Productivity, Richness and Biomass cycle with secondary succession.

K-selected Species

Population size tends to be relatively stable, well adapted to stable environments.

r-selected Species

Population can fluctuate widely, thrive in unpredictable/changing environments.

Type I Curve

Low death rate, many individuals live to old age.

Type II Curve

Moderate death rate, individuals die at all ages.

Type III Curve

High death rate, many individuals die young and few live to old age.

Overshoot

Occurs when population growth exceeds carrying capacity, leading to a die-off for individuals.

Unstable Equilibrium

The fluctuation of the population above and below the carrying capacity.

Growth Models

Exponential is J-shaped, population size doubles at a consistent rate. Logistic is S-shaped, more realistic, and has a population reach its carrying capacity and level off.

Factors Influencing Carrying Capacity

Resource availability, technological advancements, water absorption capacity, biodiversity

Doubling Time Formula

70 ÷ (annual growth rate)

Lithosphere

The outermost layer of the Earth, containing the crust and mantle.

Asthenosphere

The layer of the Earth, located in the outer part of the mantle, composed of semi-molten rock.

Divergent Boundary

An area beneath the ocean where tectonic plates move away from each other.

Seafloor Spreading

The formation of new ocean crust as a result of magma pushing upward and outward from Earth’s mantle to the surface.

Convergent Boundary

An area where plates move toward one another and collide.

Subduction Zone

A type of convergent boundary, where a denser oceanic plate sinks into the mantle underneath the lighter, continental plate. This creates a deep ocean trench, as well as volcanic activity.

Transform Boundary

An area where tectonic plates move sideways past each other.

Hot Spot

A place where molten material from Earth’s mantle reaches the lithosphere. Tends to form in the middle of plates and produce volcanic activity, similar to subduction zones.

Igneous Rock

Forms directly from magma, classified as either basaltic or granitic. Includes granite, pumice, scoria, and obsidian.

Sedimentary Rock

Formed by pressure. Multiple sediments such as mud, sands, and gravels are buried and compressed underneath other layers. Includes sandstone, shale, limestone, and gypsum.

Metamorphic Rock

Formed when sedimentary, igneous, or other metamorphic rocks are subjected to high temperatures or pressures, causing profound changes. Examples include marble, slate, gneiss, and quartzite.

Physical Weathering

The mechanical breakdown of rocks and minerals, often through water working its way into a rock and expanding via freezing.

Chemical Weathering

The breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both.

Biological Weathering

The breakdown of rocks and minerals by the exertion of physical forces and chemical reactions by a biological organism.

O-Horizon

Top soil layer. Organic matter in various stages of decomposition.

A-Horizon (topsoil)

Second soil layer. Zone of overlying organic material mixed with underlying mineral material.

E-Horizon

Third soil layer. Zone of leaching of metals and nutrients.

B-Horizon (subsoil)

Fourth soil layer. Zone of accumulation of metals and nutrients.

C-Horizon (subsoil)

Fifth soil layer. Least-weathered portion of the soil profile, similar to the parent material.

R-Layer

Lowest soil layer. Refers to the bedrock at the base of the soil that provides inorganic components to the soil via weathering.

Permeability

There is a direct correlation between permeability and particle size. Sand has the highest particle size and is the most permeable, which silt has the smallest particle size and is the least permeable.

Water-Holding Capacity

Finer-textured soils such as clay have a greater water-holding capacity due to their higher surface area, when compared to soils with larger particle sizes such as sand that have lower water-holding capacities.

Aquifers

Unconfined aquifers are made of porous rock covered by soil out of which water can easily flow, while confined aquifers are surrounded by a layer of impermeable rock or clay that impedes water flow.

Water Table

The uppermost level at which the water in a given area fully saturates rock or soil.

Groundwater Recharge

A process by which water percolates through the soil and works its way into an aquifer.

Watershed

All land in a given landscape that drains into a particular stream, river, lake, or wetland and eventually to outflow points such as reservoirs, bays, and the ocean.

Cone of Depression

An area lacking groundwater due to rapid withdrawal by a well.

Saltwater Intrusion

An infiltration of salt water in an area where groundwater pressure has been reduced from extensive drilling of wells.

Troposphere

A layer of the atmosphere closest to the surface of Earth, extending up to approximately 16 km (10 miles). Densest layer and where Earth’s weather occurs and the majority of the atmosphere’s nitrogen, oxygen and water vapor it located.

Stratosphere

The layer of the atmosphere above the troposphere, extending roughly 16 to 50 km (10–31 miles) above the surface of Earth. Natural ozone occurs here.

Mesosphere

The middle region of the Earth's atmosphere above the stratosphere and below the thermosphere, between about 30 and 50 miles (50 and 80 km) in altitude.

Thermosphere

The region of the atmosphere above the mesosphere and below the exosphere. Characterized by an increase in temperature with height; harmful UV rays are blocked and the aurora borealis occurs here.

Albedo

The percentage of incoming sunlight reflected from a surface (higher albedos mean more sunlight is reflected and less is absorbed)

Unequal Heating of the Earth

Occurs because the angle at which the Sun's rays strike varies and influences the distance the rays must travel through the atmosphere, some areas of Earth reflect more solar energy than others, and the amount of surface area over which the Sun's rays are distributed varies.

Angle of Incidence

The angle at which incoming sunlight (solar radiation) strikes the surface of the Earth. As it steepens, more sunlight is received by land surfaces (greater energy density) and it becomes warmer. The opposite is true as it becomes shallower.

Adiabatic Cooling and Heating

The cooling/heating effect of reduced/increased pressure on air as it sinks/rises and expands/contracts.

Saturation Point

The maximum amount of water vapor in the air at a given temperature.

Hadley Cell

A convection current in the atmosphere that cycles between the equator and 30° N and 30° S.

Intertropical Convergence Zone

The latitude that receives the most intense sunlight (highest angle of incidence), which causes the ascending branches of the two Hadley cells to converge.

Atmospheric Convection Currents

The vertical movement of air driven by buoyancy, where warmer, less dense air rises and cooler, denser air sinks. Powered by solar heating of the Earth's surface, they transport heat, moisture, and momentum vertically, driving wind patterns, cloud formation, and weather systems.

Ocean Circulation Patterns

Caused by differential heating, gravity, prevailing winds, the Coriolis effect, and the locations of continents.

Thermohaline Circulation

An oceanic circulation pattern that drives the mixing of surface water and deep water based on changes in the density of seawater.

Effect of Normal Conditions

Trade winds move warm, equatorial waters westward from South America toward Australia. This generates upwelling off the western South American coast and precipitation along Australia’s east coast. The resulting thermocline is relatively steep.

Effects of El Niño

Trade winds reduce in strength or reverse direction (west to east), resulting in a less steep thermocline and reduced water circulation. Precipitation moves east, away from Australia, leading to drought. Reduced upwelling off the South American coast leads to fishery collapse.

Effects of La Niña

Trade winds become especially strong pushing warm equatorial waters further west (they are normally east-to-west). This results in an especially steep thermocline. Heavy rain and flooding in eastern Australia and stronger than normal upwelling off the west coast of South America leads to fishery booms.

Primary Pollutants

Pollutants emitted directly into the atmosphere from identifiable sources (Particulate matter, Carbon Dioxide, Sulfur Dioxide, Nitrogen Oxide)

Secondary Pollutants

Pollutants formed in the atmosphere through chemical reactions involving primary pollutants and other atmospheric compounds. Examples include ground-level ozone and secondary aerosols.

Photochemical Smog

A type of air pollution formed by the reaction of sunlight with pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the atmosphere.

Thermal Inversion

Occurs when a layer of warm air traps cooler air near the ground, preventing vertical mixing of air masses.

Preliminary Treatment

The removal of large debris through screening and/or grit removal.

Primary Treatment

Holds sewage in a large containment vessel; heavy solids that sink to the bottom are removed as sludge, which is either decomposed or composted.

Secondary Treatment

The biological breakdown of dissolved organic matter. Includes activated sludge, when wastewater is mixed with bacteria and air that consume organic pollutants.

Tertiary Treatment

Includes nutrient removal, biological nutrient removal, chemical precipitation, and disinfection. Produces high-quality, treated wastewater.

Stockholm Convention

A global treaty aimed at protecting human health and the environment from Persistent Organic Pollutants (POPs), chemicals that stay in the environment for long periods, build up in organisms, and can be toxic even in small amounts.

Clean Air Act (CAA)

Regulates air emissions. Sets National Ambient Air Quality Standards.

Clean Water Act (CWA)

Regulates discharge of pollutants into surface waters (rivers, lakes). Aims to make waters "fishable and swimmable," reducing exposure to waterborne pathogens and toxins. Sets wastewater standards.

Safe Drinking Water Act (SDWA)

Sets maximum contaminant levels (MCLs) for pollutants in public drinking water supplies, including pathogens.

Furrow Irrigation

Cheapest, easiest to do, created between crop rows and then pipes/ditches are used to deliver water between them. 30% of water is lost.

Flood Irrigation

Land is flooded with water, which will infiltrate and recharge aquifers. Leads to waterlogging; 20% of water is lost to evaporation, and this method isn’t appropriate for all crops.

Spray Irrigation

Expensive; may use soil sensors, GPS, and computers. Water comes out of a spray nozzle, with 25% lost. Requires fossil fuels to run.

Drip Irrigation

Expensive and labor intensive to set up. Water must be clear of sediments/roots, or the tiny holes may become plugged. Small amounts of water are released from holes in a hose. The most efficient method, with only 5% of water lost.

Gaseous Pollutant Controls

Scrubbers, catalytic converters, and vapor recovery nozzles are all used for this.

Particulate Controls

Electrostatic precipitators and baghouses are used for this.

Birth/Death Rate

((number of births or deaths) ÷ (total population)) × (1000, or 100 for a percentage)

Crude Growth Rate

(((births+immigration) - (deaths+emigration)) ÷ (total population)) × 100

Trawl Nets

Large, cone-shaped nets are dragged along the seafloor or through midwater, scooping up everything in their path. This efficient method catches large quantities of fish but can also be destructive to marine ecosystems, leading to bycatch of unwanted species.