Unit 1: The Living World - Ecosystems

Community Ecology

The study of interactions among species

Symbiosis

Two species living in a close and long-term association with one another in an ecosystem

Biosphere

The region of our planet where life resides

Competition

The struggle of individuals, either within or between species, to obtain a shared limiting resource

Competitive Exclusion Principle

The principle stating that two species competing for the same limiting resource cannot coexist

Predation

An interaction in which one animal typically kills and consumes another animal

Parasitoid

A specialized type of predator that lays eggs inside other organisms - referred to as its host

Parasitism

An interaction in which one organism lives on or in another organism, referred to as the host

Pathogen

A parasite that causes disease in its host

Herbivory

An interaction in which an animal consumes plants or algae

Mutualism

An interaction between two species that increases the chances of survival or reproduction for both species

Photosynthesis

The process by which plants and algae use solar energy to convert carbon dioxide (CO2) and water (H20) into glucose (C6H12O6) and Oxygen (O2)

Commensalism

An interaction between two species in which one species benefits and the other species is neither harmed nor helped

Native Species

A species that lives in its historical range, typically where it has lived for thousands or millions of years

Exotic (Alien) Species

A species living outside its historical range

Invasive Species

a species that spreads rapidly across large areas and causes harm

Biome

The plants and animals that are found in a particular region of the world

Terrestrial Biome

A geographic region of land categorized by a particular combination of average annual temperature, annual precipitation, and distinctive plant growth forms

Aquatic Biome

An aquatic region characterized by a particular combination of salinity, depth, and water flow

Habitat

An area where a particular species lives in nature

Tundra

A cold and treeless biome with low-growing vegetation

Permafrost

an impermeable, permanently frozen layer of soil

Taiga (Boreal Forest)

A forest biome made up primarily of coniferous evergreen trees that can tolerate cold winters and short growing seasons

Temperate Rainforest

a coastal biome typified by moderate temperatures and high precipitation

Temperate Seasonal (Deciduous) Forest

A biome with warm summers and cold winters with over 1 m (39 inches) of precipitation annually.

Shrubland (Woodland/Chaparral)

a biome characterized by hot, dry summers and mild, rainy winters

Temperate Grassland (Cold Desert)

A biome characterized by cold, harsh winters, and hot, dry summers.

Tropical Rainforest

A warm and wet biome found between 20° N and 20° S of the equator, with little seasonal temperature variation and high precipitation.

Savanna (Tropical Seasonal Forest)

a biome marked by warm temperatures and distinct wet and dry seasons

Hot Desert

A biome located at roughly 30 N and 30 S, and characterized by hot temperatures, extremely dry conditions, and sparse vegetation

Freshwater Biomes

Categorized as streams and rivers, lakes and ponds, or freshwater wetlands

Littoral Zone

the shallow zone of soil and water in lakes and ponds where most algae and emergent plants such as cattails grow

Limnetic Zone

a zone of open water in lakes and ponds as deep as the sunlight can penetrate

Phytoplankton

floating algae

Profundal Zone

a region of water where sunlight does not reach, below the limnetic zone in very deep lakes

Benthic Zone

the muddy bottom of a lake, pond, or ocean beneath the limnetic and profundal zones

Oligotrophic

Describes a lake with a low level of phytoplankton due to low amounts of nutrients in the water

Mesotrophic

Describes a lake with a moderate level of productivity

Eutrophic

Describes a lake with a high level of fertility

Freshwater Wetland

An aquatic biome that is submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation.

Estuary

an area along the coast where the fresh water of rivers mixes with salt water from the ocean

Salt Marsh

found along the coast in temperate climates, a marsh containing non woody emergent vegetation.

Mangrove Swamp

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

Intertidal Zone

the narrow band of coastline between the levels of high tide and low tide

Coral Reef

Represents Earth's most diverse marine biome, and are found in warm, shallow waters beyond the shoreline in tropical regions

Coral Bleaching

A phenomenon in which algae inside corals die due to abnormally high water temperatures, causing the corals to turn white.

Open Ocean

Deep ocean water, located away from the shoreline where sunlight can no longer reach the ocean bottom

Photic Zone

The upper layer of ocean water in the ocean that receives enough sunlight for photosynthesis

Aphotic Zone

The deeper layer of ocean water that lacks sufficient sunlight for photosynthesis

Chemosynthesis

A process used by some bacteria to generate energy with methane and hydrogen sulfide.

Biogeochemical Cycle

the movements of matter within and between ecosystems involving cycles of biological, geological, and chemical processes

Reservoirs

The components of the biogeochemical cycle that contain matter, including air, water, and organisms

Carbon Cycle

The movement of carbon around the biosphere among reservoir sources and sinks

Steady State

When a system's input equal outputs, so that the system is not changing over time

Greenhouse Gases

Gases such as carbon dioxide, methane, nitrous oxide, water vapor, and tropospheric ozone in the atmosphere which trap heat near the surface of the Earth

Global Warming

The increase in global temperatures due to humans producing more greenhouse gases

Limiting Nutrient

a nutrient required for the growth of an organism but available in a lower quantity than other nutrients

Nitrogen Cycle

The movement of nitrogen around the biosphere among reservoir sources and sinks

Nitrogen Fixation

the process that converts nitrogen gas in the atmosphere (N2) into forms of nitrogen that plants and algae can use

Nitrification

The conversion of ammonia (NH4+) into nitrite (NO2-) and then into nitrate (NO3-)

Assimilation

A process by which plants and algae incorporate nitrogen into their tissues

Ammonification (Mineralization)

The process by which fungal and bacterial decomposers break down the organic matter found in dead bodies and waste products and convert these organic compounds back into inorganic compounds, such as inorganic ammonium (NH4+)

Denitrification

The conversion of nitrates (NO3-) in a series of steps into the gases nitrous oxide (N2O) and, eventually, nitrogen gas (N2), which is emitted into the atmosphere

Anaerobic

An environment that lacks oxygen

Aerobic

An environment with abundant oxygen

Leaching

A process in which dissolved molecules are transported through the soil via groundwater

Phosphorus Cycle

The movement of phosphorus around the biosphere among reservoir sources and sinks

Algal Bloom

A rapid increase in the algal population of a waterway

Hypoxic

Low in oxygen

Dead Zone

when oxygen concentrations become so low that it kills fish and other aquatic animals

Hydrologic Cycle

The movement of water around the biosphere among reservoir sources and sinks

Transpiration

The release of water from leaves into the atmosphere during photosynthesis

Evapotranspiration

The combined amount of evaporation and transpiration

Runoff

Water that moves across the land surface and into streams and rivers

Producers (Autotrophs)

Plants, algae, and some bacteria that use the Sun's energy to produce usable forms of energy, such as sugars

Cellular Respiration

The process by which cells unlock the energy of chemical compounds

Anaerobic Respiration

The process by which cells convert glucose into energy in the absence of oxygen

Primary Productivity

The rate of converting solar energy into organic compounds over a period of time

Gross Primary Productivity (GPP)

The total amount of solar energy that producers in an ecosystem capture via photosynthesis over a given amount of time

Net Primary Productivity (NPP)

The energy captured by producers in an ecosystem minus the energy that producers respire

Biomass

The total mass of all living matter in a specific area

Standing Crop

The amount of biomass present in an ecosystem at a particular time

Consumer (Heterotroph)

An organism that is incapable of photosynthesis and must obtain its energy by consuming other organisms

Herbivore (Primary Consumer)

A consumer that eats producers

Carnivore

A consumer that eats other consumers

Secondary Consumer

A carnivore that eats primary consumers

Tertiary Consumer

A carnivore that eats secondary consumers

Trophic Levels

The successive levels of organisms consuming one another

Food Chain

The sequence of consumption from producers through tertiary consumers

Scavenger

An organism that consumes dead animals

Detritivore

An organism that specializes in breaking down dead tissues and waste products into smaller particles

Decomposers

Fungi and bacteria that complete the breakdown process by converting organic matter into small elements and molecules that can be recycled back into the ecosystem

Ecological Efficiency

The proportion of consumed energy that can be passed from one trophic level to another

The 10% Rule

Of the total biomass available at a given trophic level, only about 10 percent can be converted into energy at the next higher trophic level

Trophic Pyramid

A representation of the distribution of biomass, numbers, or energy among trophic levels

Food Web

A model of how energy and matter move through two or more interconnected food chains