IB Environmental Science Glossary

A set of flashcards containing key terms and definitions related to IB Environmental Science.

What is an abiotic factor?

A non-living, physical factor that may influence an organism or ecosystem.

Define albedo.

The proportion of solar radiation that is reflected by a particular body or surface.

What does BOD stand for?

Biochemical oxygen demand, which measures the amount of dissolved oxygen required to break down organic material in water.

What is meant by biodegradable?

Capable of being broken down by natural biological processes.

What is biodiversity?

The amount of living diversity per unit area, including species, habitat, and genetic diversity.

Define biomass.

The mass of organic material in organisms or ecosystems, usually per unit area.

What is a biome?

A collection of ecosystems sharing similar climatic conditions.

Describe the biosphere.

That part of the Earth inhabited by organisms, extending from the atmosphere to the crust.

What is a biotic factor?

A living, biological factor that may influence an organism or ecosystem.

Define carrying capacity.

The maximum number of a species that can be sustainably supported by a given environment.

What constitutes a climax community?

A stable community of organisms in equilibrium with natural environmental conditions.

What is a community in ecological terms?

A group of populations living and interacting with each other in a common habitat.

What does competition refer to in ecology?

A common demand by two or more organisms on a limited supply of a resource.

What is correlation in ecological studies?

A measure of the association between two variables.

Define crude birth rate.

The number of births per thousand individuals in a population per year.

What is crude death rate?

The number of deaths per thousand individuals in a population per year.

What does demographic transition model describe?

Changing levels of fertility and mortality in a population over time.

Define diversity in an ecological context.

A term for heterogeneity, might refer to species, habitat, or genetic diversity.

What is genetic diversity?

The range of genetic material present in a population.

Describe habitat diversity.

The range of different habitats or number of ecological niches per unit area.

What is a diversity index?

A numerical measure of species diversity derived from species variety and abundance.

Define species diversity.

The variety of species per unit area, including number and relative abundance.

What is doubling time in population studies?

The number of years it would take a population to double at its current growth rate.

Define ecological footprint.

The area of land and water required to sustainably provide resources for a population.

What is an ecosystem?

A community of interdependent organisms and their physical environment.

Define entropy in ecological terms.

A measure of disorder or randomness in a system; higher disorder indicates higher entropy.

What is an environmental impact assessment (EIA)?

A detailed survey required before major developments to assess environmental conditions.

Describe equilibrium in an ecological context.

A state of balance among the components of a system.

What is eutrophication?

The enrichment of water bodies with nutrients, leading to oxygen depletion.

Define evolution.

The cumulative, gradual change in genetic characteristics of successive generations.

What is feedback in systems?

The return of part of the output from a system that affects succeeding outputs.

What is negative feedback?

Feedback that counteracts deviations from equilibrium to promote stability.

What is positive feedback?

Feedback that amplifies changes, leading to deviations from equilibrium.

Define fertility in human populations.

The potential for reproduction exhibited in a population.

What is the Gaia hypothesis?

Concept comparing Earth to a living organism maintained by feedback mechanisms.

What is global warming?

An increase in the average temperature of the Earth’s atmosphere.

What are greenhouse gases?

Gases that absorb infrared radiation, contributing to the greenhouse effect.

Define habitat.

The environment in which a species normally lives.

What are halogenated organic gases?

Potent greenhouse gases first identified as depleting the ozone layer.

What is isolation in ecological terms?

When two populations are separated, preventing gene flow and potentially leading to speciation.

What is the meaning of a K strategist?

Species that invest in few offspring to enhance survival and adaptation in stable environments.

Define latitude.

The angular distance from the equator, measured in degrees.

What is an LEDC?

Less economically developed country with low to moderate industrialization.

What is an MEDC?

More economically developed country with high industrialization.

Define a model in ecology.

A simplified description showing the structure or workings of a system or concept.

What is mutualism?

A relationship where individuals of two or more species benefit from each other.

What is natural capital?

Natural resources that can produce a 'natural income' of goods and services.

Define non-renewable natural capital.

Natural resources that cannot be replenished within the same timescale they are used.

What is renewable natural capital?

Natural resources with sustainable yields equal to or less than their natural productivity.

What is a niche?

A species' share of a habitat and the resources in it.

Define parasitism.

A relationship where one species lives on or in another, gaining food at the host's expense.

What is plate tectonics?

The movement of rigid plates of the Earth's lithosphere in relation to each other.

Define pollution.

The addition of harmful substances to an environment by human activity.

What is point source pollution?

Pollutants released from a single, identifiable site.

What does population mean in ecology?

A group of organisms of the same species living in the same area.

Define gross primary productivity (GPP).

The total gain in energy or biomass by photosynthesis in green plants.

What is net productivity?

The gain in energy or biomass remaining after allowing for respiratory losses.

What is the difference between gross secondary productivity (GSP) and net secondary productivity (NSP)?

GSP is total gain by consumers, NSP accounts for energy losses.

What does stable equilibrium refer to?

A system condition where it returns to equilibrium after disturbance.

What is standing crop?

The total biomass of an organism at a specific time.

Define succession.

The orderly process of change in a community over time.

What is sustainability?

Using global resources at a rate that allows natural regeneration and minimizes environmental damage.

What is a system?

A set of inter-related parts working together to make a complex whole.

Define a closed system.

A system that exchanges energy but not matter with its surroundings.

What is an isolated system?

A system that exchanges neither matter nor energy with its surroundings.

What does an open system entail?

A system where both matter and energy are exchanged with its surroundings.

What is transfer in ecological terms?

When energy or matter flows and changes location without changing state.

Define transformation in ecology.

When energy or matter flows and changes its state.

What is a tipping point?

A critical threshold where small changes can lead to significant effects.

Define trophic level.

The position that an organism occupies in a food chain.

What is zonation?

The arrangement of plant communities in response to changes in environmental factors.

What is replenishable natural capital

non-living natural resources that depend on the energy of the sun for their replenishment; example, groundwater

What is the rate of natural increase

the form in which human population growth rates are usually expressed; inward and outward migration is ignored

non-point source pollution

the release of pollutants from numerous, widely dispersed origins; example: gases from the exhaust systems of vehicles

Gross productivity

The total gain in energy or biomass per unit area per unit time, which could be through photosynthesis in primary producers or absorption in consumers.

Productivity, gross secondary (GSP)

The total gain by consumers in energy or biomass per unit area per unit time through absorption.

Productivity, net (NP)

The gain in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R). Other metabolic losses may take place, but these may be ignored when calculating and defining net productivity for the purpose of this course.

Productivity, net primary (NPP)

The gain by producers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R). This is potentially available to consumers in an ecosystem.

Productivity, net secondary (NSP)

The gain by consumers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R).

primary productivity

the gain by producers in energy or biomass per unit area per unit time; either gross or net primary productivity

secondary productivity

The biomass gained by heterotrophic organisms, through feeding and absorption, measured in units of mass or energy per unit area per unit time.

Sere

the set of communities that succeed one another over the course of succession at a given location

smog

the term now used for any haziness in the atmosphere caused by air pollutants. Photochemical smog is produced hrough the effect of ultraviolet light on the products of internal combustion engines. It may contain ozone and is damaging to the human respiratory system and eyes.

society

An arbitrary group of individuals who share some common characteristic such as geographical location, cultural background, historical timeframe, religious perspective, value system, and so on.

Soil

A mixture of mineral particles and organic material that covers the land, and in which terrestrial plants grow.

Soil profile

A vertical section through a soil, from the surface down to the parent material, revealing the soil layers or horizons.