Ecology and Biomes: Key Concepts and Definitions

Abiotic

Non-living chemical and physical parts of the environment that affect living organisms.

Biotic

Living components of an ecosystem, including plants, animals, and microorganisms.

Range of Tolerance

The limits of abiotic conditions that an organism can tolerate.

Limiting Factor/Resource

Any environmental factor that restricts the growth, abundance, or distribution of an organism.

Species Distribution

The manner in which a biological taxon is spatially arranged.

Adaptation

A characteristic that enhances the survival and reproduction of organisms in a specific environment.

Biome

A large ecological area on the earth's surface with flora and fauna adapting to their environment.

Taiga/Boreal Forest

A biome characterized by coniferous forests, cold temperatures, and moderate precipitation.

Temperate Grassland

A biome characterized by grasses, moderate rainfall, and distinct seasons.

Tropical Grassland/Savanna

A biome with grasslands and scattered trees, found in tropical regions with a seasonal rainfall pattern.

Temperate Seasonal Forest

A biome characterized by deciduous trees that lose their leaves in winter and experience moderate climate.

Tropical Rainforest

A biome characterized by high rainfall, high humidity, and a diverse range of species.

Tundra

A cold biome characterized by permafrost, low temperatures, and minimal vegetation.

Subtropical Desert

A biome characterized by low rainfall, high temperatures, and sparse vegetation.

Temperate Rainforest

A biome characterized by high rainfall, moderate temperatures, and dense forests.

Shrubland/Chaparral

A biome characterized by dense shrubs and periodic fires, typically found in Mediterranean climates.

Species Richness

The number of different species represented in a given ecological community.

Species Evenness

A measure of how equal the abundances of different species are in a community.

Fundamental Niche

The full range of environmental conditions under which a species can survive and reproduce.

Realized Niche

The actual conditions and resources in which a species exists due to interactions with other species.

Niche Generalist

A species that can thrive in a wide variety of environmental conditions and can utilize a variety of resources.

Niche Specialist

A species that has a narrow ecological niche and specific habitat requirements.

Mass Extinction

A significant and rapid decrease in the number of species on Earth, typically due to catastrophic events.

Genetic Diversity

The total number of genetic characteristics in the genetic makeup of a species.

Species Diversity

The variety of species within a given ecosystem or area.

Functional Diversity

The variety of processes and functions that different species perform in an ecosystem.

Ecological Diversity

The variety of ecosystems within a given region or the diversity of species within those ecosystems.

Resiliency

The ability of an ecosystem to recover from disturbances or changes.

Stability

The ability of an ecosystem to maintain its structure and function over time despite disturbances.

Ecosystem Services

The benefits that humans derive from ecosystems, including provisioning, regulating, cultural, and supporting services.

Regulating Services

Ecosystem services that regulate environmental conditions, such as climate regulation and water purification.

Provisioning Services

Ecosystem services that provide raw materials, such as food, water, and timber.

Cultural Services

Non-material benefits obtained from ecosystems, including recreation, aesthetic enjoyment, and spiritual fulfillment.

Supporting Services

Services that maintain the conditions for life on Earth, such as soil formation and nutrient cycling.

Genotype

The genetic constitution of an individual organism.

Phenotype

The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

Genetic Variation

Differences in DNA sequences among individuals within a population.

Mutation

A change in the DNA sequence of an organism that can lead to genetic diversity.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Speciation

The formation of new and distinct species in the course of evolution.

Theory of Island Biogeography

A theory that explains the number of species on an island based on its size and distance from the mainland.

Aquatic

Relating to water; ecosystems that are based in water.

Marine

Relating to the sea; ecosystems that are based in saltwater.

Littoral Zone

The nearshore area of a body of water where sunlight penetrates and aquatic plants grow.

Limnetic Zone

The open water area of a lake or pond that is well-lit and supports photosynthesis.

Benthic Zone

The lowest ecological zone in a body of water, consisting of the sediment surface and sub-surface layers.

Oligotrophic

Describes a body of water that is low in nutrients and supports little plant life.

Mesotrophic

Describes a body of water with a moderate level of nutrients and productivity.

Eutrophic

Describes a body of water that is rich in nutrients and supports a high level of plant growth.

Freshwater Wetland

An area of land that is saturated with water, either permanently or seasonally, and supports aquatic plants.

Salt Marsh

A coastal wetland that is flooded and drained by salt water brought in by the tides.

Estuary

A coastal area where freshwater from rivers meets and mixes with saltwater from the ocean.

Mangrove Swamp

A coastal wetland found in tropical and subtropical regions, characterized by salt-tolerant trees.

Intertidal Zone

The area of the shoreline that is exposed to the air at low tide and submerged at high tide.

Coral Reef

A marine ecosystem characterized by reef-building corals, which provide habitat for diverse marine species.

Photic Zone

The upper layer of a body of water that receives enough sunlight for photosynthesis.

Aphotic Zone

The deeper layer of a body of water that lacks sufficient sunlight for photosynthesis.

Chemosynthesis

The process by which certain organisms create energy from inorganic compounds, typically in the absence of sunlight.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with carbon dioxide and water.

Keystone Species

A species that has a disproportionately large effect on its environment relative to its abundance.

Ecosystem Engineer/Foundation Species

A species that creates, modifies, or maintains habitats for other species.

Primary Succession

The process of ecological succession that occurs in an area where no soil exists, such as after a volcanic eruption.

Secondary Succession

The process of ecological succession that occurs in an area where a disturbance has destroyed an existing community but soil remains.

Pioneer Species

The first species to colonize previously disrupted or damaged ecosystems.

Early Successional Species

Species that thrive in disturbed environments and are typically the first to establish after a disturbance.

Late Successional Species

Species that establish later in succession and are often larger and longer-lived.

Climax Community

A stable and mature ecological community that undergoes little or no change in species composition.

Facilitation

A process in ecological succession where one species makes it easier for another species to establish.

Inhibition

A process in ecological succession where one species prevents the establishment of another species.

Intermediate Disturbance Hypothesis

The hypothesis that ecosystems experiencing intermediate levels of disturbance will have higher levels of species diversity.

Cellular Respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Anaerobic Respiration

The process of producing cellular energy without oxygen.

Decomposition

The process by which organic substances are broken down into simpler organic or inorganic matter.

Autotroph

An organism that produces its own food through photosynthesis or chemosynthesis.

Heterotroph

An organism that obtains its food by consuming other organisms.

Trophic Level

The position an organism occupies in a food chain, which determines its role in the flow of energy and nutrients.

Primary Producer

Organisms, such as plants and algae, that produce energy through photosynthesis.

Primary Consumer

Herbivores that consume primary producers.

Secondary Consumer

Carnivores that eat primary consumers.

Tertiary Consumer

Carnivores that eat secondary consumers.

Trophic Pyramids

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

Ecological Efficiency

The efficiency with which energy is transferred from one trophic level to the next.

Combustion

The process of burning organic material in the presence of oxygen, releasing energy, carbon dioxide, and water.

Fossil Fuels

Natural fuels formed from the remains of ancient organisms, including coal, oil, and natural gas.

Carbon Fixation

The process of converting inorganic carbon (CO2) into organic compounds by living organisms.

Nitrogen Fixation

The process of converting atmospheric nitrogen (N2) into a form usable by living organisms.

Nitrification

The process by which ammonia is converted into nitrites and then nitrates by bacteria.

Ammonification

The process of converting organic nitrogen into ammonia by decomposers.

Denitrification

The process by which nitrates are reduced to nitrogen gas, returning it to the atmosphere.

Assimilation

The process by which plants and animals incorporate nutrients from the environment into their tissues.

Haber Process

An industrial process for synthesizing ammonia from nitrogen and hydrogen gases.

Symbiosis

A close and long-term interaction between two different biological species.

Mutualism

A type of symbiotic relationship where both species benefit.

Commensalism

A type of symbiotic relationship where one species benefits and the other is neither helped nor harmed.

Parasitism

A type of symbiotic relationship where one species benefits at the expense of the other.

Parasitoidism

A relationship where one organism lives on or in another organism and ultimately kills it.

Pathogen

An organism that causes disease in another organism.

Herbivory

The act of eating plants by herbivores.

Competition (Intra, Intersp.)

The struggle between organisms for the same resources in an ecosystem; intra-competition occurs within a species, while inter-competition occurs between different species.

Resource Partitioning

The division of resources among species to reduce competition.