82 terms

IB Environmental Systems & Societies 2018

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Population
A group of organisms of the same species populating a given area
A group of organisms of one species that interbreed and live in the same place at the same time
Species
A group of similar organisms that can breed and produce fertile offspring.
Steady-state equilibrium
The condition of an open system in which there are no changes over the longer term, but where there may be oscillations in the very short term. There are continuing inputs and outputs of matter and energy, but the system as a whole remains in a more or less constant state (e.g climax ecosystem).
Correlation
A measure of the association between variables. If 2 variables move up or down together, they are said to be positively correlated. If the tend to move in opposite directions, they are negatively correlated.
Parasitism
A relationship between two species in which one species (the parasite) lives in or on another (the host), gaining all or much (partial parasite) of its food from it.
Succession
The orderly process of change over time in a community of organisms frequently cause changes in the physical environment that allow another community to become established and replace the former through competition. Often later communities are more complex than earlier.
Sustainability
Use of global resources at a rate that allows natural regeneration and minimises damage to the environment. For example a system of harvesting renewable resources at a rate that will be replaced by natural growth might be considered to demonstrate sustainability
Gaia hypothesis
Developed by James Lovelock and named after an Ancient Greek Earth goddess, compares the earth to a living organism in which feedback mechanisms maintain equilibrium.
Competition
A common demand by two or more rganisms upon a limited supply of a resource- food, water, light, space, mates, nesting sites. It may be interspecific or intraspecific.
Stable equilibrium
The condition of a system in which there is a tendancy for it to return to a previous equilibrium condition following disturbance.
Fertility
In the context of human populations, this refers to the potential for reproduction exhibited in a population. May be measured as fertility rate, which is the number of births per thousand women of child-bearing age. Alternatively measured as total fertility, which is simply the average number of children a woman has in her lifetime.
Speciation
the process by which new species are generated
Natural capital
A term sometimes used by economists for natural resources that, if appropriately managed, can produce a 'natural income' of goods and services. The natural capital of a forest might provide a continuing natural income of timber, game, water & recreation.
Natural capital non-renewable
Natural resources that cannot be replenished within a timescale of the same order as which they were taken from the environment. E.g fossil fuels
Natural capital replenishable
Non-living natural resources that depend on the energy of the sun for their replenishment. E.g groundwater
Rate of natural increase
The form in which human population growth rates are usually expressed.

Crude birth rate - crude death rate/ (divided) by 10.

Inward & outward migration is ignored.
Niche
A species' share of a habitat and the resources within it. An organisms ecological niche depends not only on where it lives but also on what it does.
Mutualism
A relationship between two species in which both species benefit
Isolation
The process by which two populations become separated by geographical, behavioural, genetic or reproductive factors. If genes flow between the two subpipulations is prevented, new species may evolve - evolution.
K-Strategist
Species that usually concentrate their reproductive investment in a small number of off-spring, thus increasing their survival rTe and adapting them for living in long term climax communities.
Sere
The set of communities that succeed one another over the course of succession at a given location.
System
An assembly of parts and the relationships between them, which together constitute an entity or whole
Ecosystem
A community of interdependent organisms and the physical environment the inhabit.
Habitat
The environment in which a species normally lives.
Isolated system
A system that doesn't exchange matter or energy with its surroundings
Open system
A system where both matter and Energy are exchanged with its surroundings. E.g natural ecosystems
Closed system
A system in which energy, but not matter, is exchanged with its surroundings
Trophic level
the position in a food chain occupied by a group of organisms with similar feeding modes.
Zonation
Changes in the physical and biological structures of communities as one moves across the landscape
Biosphere
part of Earth in which life exists including land, water, and air or atmosphere. The part of the earth which is inhabited by organisms, that is the narrow zone ( few Kim's thick) in which plants and animals exist. It extends from the earths crust to the upper atmosphere
Plate tectonics
The movement of the 8 major and several minor internal rigid plates of the earths lithosphere in relation to each other and to the partially mobile asthenosphere below.
Model
A simplified description designed to show the structure or workings of an object, system or concept.
Latitude
The angular distance from the equator (either north or south) as measured from the centre of the earth ( in degrees).
Entropy
A measure of the amount of disorder, chaos or randomness in a system; the greater the disorder, the higher the level of entropy
Evolution
The culmination, gradual change in the genetic characteristics of successive generations of a species or race of an organism, ultimately giving rise to a different species or race from a common ancestor. It reflects changes in the genetic composition of a population over time. E.g all. Dog breeds originated from the wolf.
Environmental Impact Assessment (EIA)
study/process/overall assessment of a project's impact on the environment. Includes a baseline study to measure environmental conditions and identify areas and species of conservation importance.
A method of detailed survey required in many countries prior to major development. Should be done independent of, but paid for by the developer. The report produced is known as an environmental impact statement (EIS) or environmental management review. Monitoring should continue for some time after development
Global warming
An increase in average temperature of the earths atmosphere
GNP
Gross national Product (GNP) is the current value of all goods and services produced in a country per year.
Greenhouse gases
Atmospheric gases which absorb infrared radiation causing world temperatures to become warmer than they may otherwise be- known as radiation trapping. The natural greenhouse effect is caused mainly by water and CO2, Methane and nitrous oxide (N2O) in the atmosphere. There are fears this may lead to global warming.
Pollution
The addition to an environment of a substance or an agent ( such as heat) by human activity, at a rate greater than that at which it can be rendered harmless by the environment, and which has an effect on the organisms within it.
Non-point source pollution
The release of pollutants from numerous, widely dispersed origins. E.g gases from exhaust systems of vehicles or spraying pesticides
Point source pollution
The release of pollutants from a single, clearly identifiable site. E.g a factory chimney or the waste pipe of a factory flowing into a river.
Society
An arbitrary group of individuals who share some common characteristics such as geographical location, cultural background, historical timeframe, religious perspective, value system etc.
LEDC
Less economically developed country: a country with low to moderate industrialisation and average GNP per capita.
MEDC
More economically developed country: a highly industrialised country with a higher average GNP per capita
Demographic transition
A general model describing the changing levels of fertility and mortality in human population over time. It was developed with reference to the transition experienced as developed countries (eg North America, Europe, Australasia) passed through the processes of industrialisation and urbanisation.
Carrying capacity
The maximum number of a species or 'load' that can be sustainably supported by a given environment.
Diversity
A generic term for heterogeneity. The scientific meaning of diversity becomes clear from the context of which it was used; may refer to heterogeneity of species, habitat or genetics.
Genetic diversity
The range of genetic material present in a gene pool or a population of a species.
Habitat diversity
The range of different habitats or number of ecological niches per unit area of an ecosystem, community or biome. Conservation of habitat diversity usually leads to the conservation of species and genetic diversity
Diversity index
A numerical measure of species diversity that is derived from both the number of species (variety) and their abundance.
Species diversity
The variety of species per unit area. This includes both the number of species present and their relative abundance.
Doubling time
The number of years it would take a population to double at its current growth rate. A natura, increase of 1% will enable a human population to double in 70 years. Other doubling times can be calculated proportionally ( doubling time = to 70 divided by the natural increase rate).
Ecological footprint
The area of land and water required to support a defined human population at a given standard of living. The measure takes account of the area required to provide all the resources needed by the population and the assimilation of all wastes. (3.8.2 calculation)
Crude death rate
Number of deaths per thousand individuals in a population per year.
Crude birth rate
The number of births per thousand individuals per year.
Community
A group of populations living and interacting with each other in a common habitat.
Climax community
A community of organisms that is more or less stable, and that is in equilibrium with natural environmental conditions such as climate, the end point of ecological succession.
Gross productivity (GP)
The total gain in energy or biomass per unit area per unit time, which can be through photosynthesis in primary producers or absorption in consumers.
Gross Primary Productivity (GPP)
Total gain in energy or biomass per unit area per unit time fixed by photosynthesis in green plants.
Equivalent to mass of glucose created by photosynthesis.
Gross Secondary Productivity (GSP)
The total gain by consumers in energy or biomass per unit area per unit time through absorption.
GSP= food eaten - faecal loss (human waste)
Net productivity (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.
Net Primary Productivity (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.
NPP= GPP - R
Net secondary productivity (NSP)
The gain by consumers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R)
NSP= GSP - R
Primary productivity
The gain by producers in energy or biomass per unit area per unit time.
This term can either refer to 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.
R- strategist
Species that tend to spread their reproductive investment among a large number of off-spring so that they are well adapted to colonise new habitats rapidly and make opportunist use of short- lived resources.
Equilibrium
A state of balance among the components of a system.
Eutrophication
The natural or artificial enrichment of a body of water, particularly with respect to nitrates and phosphates, that results in depletion of the oxygen content of the water. Eutrophication is accelerated by human activities that add detergents, sewage or agricultural fertilisers to bodies of water.
Feedback
The return of part of the output from a system as an input, so as to affect succeeding outputs
Negative feedback
Feedback that tends to dampen down, neutralise or counteract any deviation from an equilibrium and promote stability.
Positive feedback
Feedback that amplifies and increases chNge, leads to exponential deviation away from an equilibrium
Soil profile
A vertical section through a soil from the surface down to the parent material revealing the soil layers or horizon
Abiotic factor
A non-living, physical factor that may influence an organism or ecosystem. E.g temperature, sunlight, pH, salinity, precipitation (rain)
Halogenated organic gases
Usually known as halocarbons and first identified as depleting the ozone layer in the stratosphere. Now k own to be potent greenhouse gases. The most well k own are chlorofluorocarbons (CFCs)
Biochemical oxygen demand (BOD)
A measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity.
Biodegradable
Capable of being broken down by natural biological processes. E.g the activities of decomposer organisms.
Biomass
The mass of organic material in organisms or ecosystems, usually per unit area.'Dry weight biomass' refers to where mass is used after the re oval of water. Water is not organic material and I organic material is usually relatively I significant in terms of mass.
Standing crop
The mass of organic material in organisms or ecosystems, usually per unit area.'Dry weight biomass' refers to where mass is used after the re oval of water. Water is not organic material and organic material is usually relatively I significant in terms of mass. (Same as biomass)
Biome
A collection of ecosystems sharing similar climatic conditions. E.g tundra, tropical rainforest, desert.
Biotic factor
A living biological factor that may influence an organism or Eco-system. E.g predation, parasitism, disease, competition.
Smog
The term used for any haziness in the atmosphere caused by air pollutants. Photochemical smog is produced through the effect of ultraviolet light on the products of I termal combustion engines. It may contain ozone and is damaging to the human respiratory system and eyes.