Unit 1: The Living World: Ecosystems

Climate

Climate is the long-term pattern of temperature, precipitation, and other weather conditions in a particular area.

Resource Partitioning

Resource partitioning occurs when species divide available resources in different ways to reduce competition with one another.

Competitive Exclusion Principle

The competitive exclusion principle states that two species cannot occupy the exact same niche indefinitely if they compete for the same limiting resource.

Parasitoid

A parasitoid is an organism that lives on or inside a host and eventually kills the host.

Pathogen

A pathogen is an organism or agent that causes disease in another organism.

Herbivory

Herbivory occurs when an animal feeds on plants or algae.

Photosynthesis

Photosynthesis is the process in which plants, algae, and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen.

Primary Productivity

Primary productivity is the rate at which producers create organic matter from inorganic substances.

Denitrification

Denitrification is the process in which bacteria convert nitrates into nitrogen gas, returning nitrogen to the atmosphere.

Permafrost

Permafrost is soil or rock that remains frozen for at least two consecutive years.

Assimilation

Assimilation is the process in which organisms absorb and incorporate nutrients into their tissues.

Littoral Zone

The littoral zone is the shallow area along the edge of a lake where sunlight reaches the bottom and aquatic plants can grow.

Limnetic Zone

The limnetic zone is the open, sunlit area of a lake that is away from the shore.

Phytoplankton

Phytoplankton are microscopic, photosynthetic organisms that float in aquatic environments and form the base of many aquatic food webs.

Profundal Zone

The profundal zone is the deep region of a lake below the limnetic zone where little or no sunlight reaches.

Benthic Zone

The benthic zone is the bottom region of a body of water where organisms live in or on the sediments.

Oligotrophic

A body of water is oligotrophic when it has low nutrient levels, low productivity, and generally clear water.

Mesotrophic

A body of water is mesotrophic when it has moderate nutrient levels and moderate biological productivity.

Eutrophic

A body of water is eutrophic when it contains high nutrient levels that support high productivity and can cause excessive algal growth.

Photic Zone

The photic zone is the upper layer of a body of water where enough sunlight is available for photosynthesis.

Aphotic Zone

The aphotic zone is the deeper layer of a body of water where there is not enough sunlight for photosynthesis.

Gross Primary Productivity (GPP)

Gross primary productivity is the total amount of energy captured by producers through photosynthesis before energy is used for cellular respiration.

Phosphorus Cycle

The phosphorus cycle describes how phosphorus moves through rocks, soil, water, and living organisms.

Net Primary Productivity (NPP)

Net primary productivity is the amount of energy stored by producers after the energy used for cellular respiration is subtracted from GPP.

Hypoxic

An environment is hypoxic when it contains very low levels of dissolved oxygen.

Dead Zone

A dead zone is an area of water with extremely low oxygen levels where most aquatic organisms cannot survive.

Evapotranspiration

Evapotranspiration is the combined process of water evaporating from surfaces and being released by plants through transpiration.

Cellular Respiration

Cellular respiration is the process cells use to break down glucose and release energy in the form of ATP.

Nitrogen Fixation

Nitrogen fixation is the process of converting atmospheric nitrogen gas into a form of nitrogen that organisms can use.

Limiting Nutrient

A limiting nutrient is a nutrient that restricts the growth or productivity of organisms because it is in the shortest supply relative to their needs.

Nitrification

Nitrification is the process in which bacteria convert ammonia into nitrites and then into nitrates.

Resource Partitioning

Resource partitioning occurs when species divide available resources in different ways to reduce competition with one another.

1st law of thermodynamics

The first law of thermodynamics states that energy cannot be created or destroyed, but it can be transferred or transformed.

2nd law of thermodynamics

The second law of thermodynamics states that every energy transfer increases entropy and causes some energy to be lost as heat.

Carbon Sink

A carbon sink is a reservoir that absorbs and stores more carbon than it releases.

Intraspecific Competition

Intraspecific competition occurs when individuals of the same species compete with one another for limited resources.

Interspecific Competition

Interspecific competition occurs when individuals of different species compete with one another for limited resources.

Endemic Species

An endemic species is a species that naturally occurs only in a specific geographic area.

Leaching

Leaching is the process in which water carries dissolved nutrients and minerals downward through soil.

Native Species

A native species is a species that naturally occurs in a particular region without being introduced by humans.