Ecosystems and Ecosystem Services

Vocabulary flashcards covering the concepts, definitions, classifications, and quantitative thermodynamics of ecosystems and ecosystem services.

Ecosystem Services

The beneficial outcomes and goods and services derived from natural and managed ecosystems upon which human welfare depends, resulting directly from ecosystem functions.

Provisioning Services

Ecosystem services that provide tangible products obtained by humans from ecosystems, such as freshwater, food, fibers, genetic resources, raw materials, and energy.

Regulating Services

Benefits obtained from the regulation of ecosystem processes, including climate regulation, water purification, flood damage control, erosion control, pollination, and disease and pest control.

Cultural Services

Non-material benefits that humans obtain from ecosystems through cognitive development, recreation, ecotourism, spiritual enrichment, reflection, and aesthetic experiences.

Supporting Services

Basic ecological functions and assets necessary for the production of all other ecosystem services, including nutrient cycling, primary production, soil formation, photosynthesis, and habitat provisioning.

Direct Values

Economic values placed on ecosystem outputs that can be consumed or processed directly, such as timber, fodder, fuel, meat, medicines, and wild foods.

Indirect Values

Economic values assigned to ecological services that support human activities indirectly, such as flood control, regulation of water flows, nutrient retention, and climate regulation.

Option Values

The premium placed on maintaining ecological resources and landscapes for future possible direct and indirect uses, including uses that may not yet be known.

Existence Values

The intrinsic non-use value of resources and landscapes irrespective of human consumption, such as cultural, aesthetic, and bequest significance.

National Plant Genetic Resources Program (NPGRP)

A program initiated in 2003 in Finland designed to preserve genetic materials obtained from forestry plants and agricultural lands to counter diversity loss.

Ecosystem

An ecological system consisting of a community of organisms and their physical environment interacting together as a functional system, a term first coined by English botanist A.G. Tansley in 1935.

Abiotic Components

The nonliving physical and chemical parts of an ecosystem, including solar radiation, inorganic substances (such as sulfur and boron), and organic compounds (proteins, carbohydrates, lipids).

Photoautotrophs

Primary producers (such as green plants, algae, and some bacteria) that capture light energy from the sun and synthesize complex organic compounds from simple inorganic compounds.

Chemoautotrophs

Chemosynthetic bacteria that synthesize complex organic compounds by oxidizing reduced inorganic substances, typically sulfur and ammonia compounds, using oxygen.

Heterotrophs

Organisms that cannot produce their own food directly from sunlight and inorganic substances and therefore rely on energy stored in the complex organic molecules of other organisms.

First Law of Thermodynamics

The physical principle stating that energy can be transformed from one form to another, but it cannot be created or destroyed.

Second Law of Thermodynamics

The physical principle stating that energy transformations always result in dissipation or loss of usable energy as heat, causing entropy (unavailable energy) in a closed system to increase.

Trophic Structure

The organization and pattern of energy and nutrient flow among different feeding levels (producers, consumers, and decomposers) within an ecosystem.

Detritivores

Invertebrate consumers that feed directly on detritus, which consists of organic wastes and dead organisms derived from all trophic levels.

Decomposers

Organisms, specifically bacteria and fungi, that break down dead organic matter and return it into inorganic nutrients for the ecosystem.

Food Web

A network of multiple interconnected food chains that illustrates the complex, non-linear feeding interactions among organisms within an ecosystem.

Y-shaped Energy Flow Model

An ecological model introduced by E.P. Odum in 1983 depicting the simultaneous flow of solar energy and the functional linkages between the grazing food chain and the detritus food chain.

Pyramid of Energy

An ecological pyramid showing the rate of energy flow or productivity at each trophic level, which is always upright because energy is lost as heat via respiration at each step.

Pyramid of Numbers

An ecological diagram indicating the total count of individual organisms present at each trophic level, without accounting for organism size or biomass.

Pyramid of Standing Crop

An ecological diagram indicating the total biomass present in each trophic level at a specific point in time.

Inverted Pyramid

A pyramid of biomass or numbers where a higher trophic level exceeds a lower level, occurring when primary producers have very high turnover and productivity rates despite a small standing crop.

Gross Primary Production (GPP)

The total rate at which autotrophs assimilate solar energy and convert it into chemical energy through photosynthesis.

Net Primary Production (NPP)

The rate of organic matter storage in plant tissues exceeding respiratory losses, calculated as $\text{NPP} = \text{GPP} - R$.

Secondary Productivity (SP)

The rate at which energy is stored as new biomass at the consumer (heterotrophic) levels of an ecosystem.

Production Efficiency

The percentage of assimilated energy stored as new biomass that is not expended in cellular respiration, defined by the formula $\text{Production efficiency} = \frac{\text{net production}}{\text{assimilation}} \times 100$.

Consumption Efficiency

The percentage of total productivity at one trophic level that is ingested by organisms at the next trophic level, calculated as $\text{Consumption Efficiency} = \frac{\text{Intake at trophic level } n}{\text{Net production at trophic level } n-1} \times 100$.

Trophic-Level Transfer Efficiency

The proportion of production or energy assimilated at one trophic level that is transferred to the next trophic level, typically ranging between $5\%$ and $20\%$, given by $\text{Trophic-level transfer efficiency} = \frac{\text{assimilation at trophic level } n}{\text{assimilation at trophic level } n-1} \times 100$.