Ecology Chapter 2

Climate

The typical atmospheric conditions that occur throughout the year, measured over many years.

Weather

Variation in temperature and precipitation over periods of hours or days.

Greenhouse effect

The process of solar radiation striking Earth, being converted to infrared radiation, and being absorbed and re-emitted by atmospheric gases.

Albedo

The fraction of solar energy reflected by an object.

Saturation point

The limit of the amount of water vapor that the air can contain.

Intertropical convergence zone (ITCZ)

The area where the two Hadley cells converge and cause large amounts of precipitation.

Polar cells

The atmospheric convection currents that move air between 60° and 90° latitudes in the Northern and Southern hemispheres.

Ferrel cells

Areas of atmospheric currents lacking patterns.

Adiabatic cooling

Due to reduced pressure on air as it rises higher and expands.

Adiabatic heating

Due to increased pressure on air as it sinks and decreases in volume.

Latent heat release

When water vapor is converted back to liquid, water releases energy in the form of heat.

Gyre

Large-scale water circulation pattern between continents.

Upwelling

An upward movement of ocean water.

Thermohaline circulation

A global pattern of surface- and deep-water currents that flow due to variations in temperature and salinity that change the density of water.

Rain shadow

A region with dry conditions found on the leeward side of a mountain range as a result of humid winds from the ocean, causing precipitation on the windward side.

Biome

A geographic region containing communities composed of organisms with similar adaptations.

Convergent evolution

Unrelated species evolve to have similar characteristics under similar selective pressures.

Climate diagram

A graph that plots the average monthly temperature and precipitation of a specific location on Earth.

Lotic

Characterized by flowing water.

Stream

Narrow channel of fast-flowing fresh water.

River

Wide channel of slow-flowing fresh water.

Riparian zone

Adjacent land influenced by flooding.

Allochthonous

Inputs from outside (example: leaves).

Autochthonous

Inputs produced by algae and aquatic plants inside the ecosystem.

Ponds and lakes

Characterized by nonflowing fresh water with at least some area of water that is too deep for plants to rise above the water’s surface.

Littoral zone

The shallow area around the edge of a lake or pond containing rooted vegetation.

Limnetic zone

The open water beyond the littoral zone, where the dominant photosynthetic organisms are floating algae; also known as the pelagic zone.

Profundal zone

The area in a lake that is too deep to receive sunlight.

Benthic zone

The area consisting of the sediments at the bottoms of lakes, ponds, and oceans.

Stratification

The condition of a lake or pond when the warmer, less dense surface water floats on the cooler, denser water below.

Epilimnion

The surface layer of the water in a lake or pond.

Hypolimnion

The deeper layer of water in a lake or pond.

Estuaries

An area along the coast where the mouths of freshwater rivers mix with the salt water from oceans.

Salt marshes

A saltwater biome that contains nonwoody emergent vegetation.

Mangrove swamp

A biome that occurs along tropical and subtropical coasts and contains salt-tolerant trees with roots submerged in water.

Intertidal zone

A biome consisting of the narrow band of coastline between the levels of high tide and low tide.

Open ocean

The part of the ocean that is away from the shoreline and coral reefs. Open oceans cover the largest portion of the surface of Earth.

Neritic zone

The ocean zone that is beyond the range of the lowest tidal level and extends to depths of about 200 m.

Oceanic zone

The ocean zone beyond the neritic zone.

Photic zone

The area of the neritic and oceanic zones that contains sufficient light for photosynthesis by algae.

Aphotic zone

The area of the neritic and oceanic zones where the water is so deep that sunlight cannot penetrate.