ESS All Topics

Environmental Value System

Worldview that shapes the way an individual or group of people perceive and evaluate environmental issues.

System

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

Open System

Exchanges matter and energy with its surroundings

Closed System

Exchanges energy but not matter with its surroundings

Isolated System

Exchanges neither matter nor energy

Transfer

Occurs when energy or matter flows and changes location

Transformation

Occurs when energy of matter flows and changes its state

Model

A simplified version of the real thing

Strengths of Models

Easier to work with than complex reality / helps us see patterns / used to visualize really small or big things

Weaknesses of Models

Accuracy is lost as it is simplified / predictions may be inaccurate / assumptions are wrong means model is wrong

First Law of Thermodynamics

States that energy in an isolated system can be transformed but cannot be created or destroyed

Second Law of Thermodynamics

The fact that energy is transformed through energy transfers

Entropy

The measure of the amount of disorder in a system

Efficiency

energy produced / energy consumed

Steady-State Equilibrium

Where there are continuous inputs and outputs of energy and matter but the system as a whole remains in a constant state

Static Equilibrium

Where there is no change over time

Stable Equilibrium

Returns to the same equilibrium after a disturbance

Unstable Equilibrium

System returns to a new equilibrium after a disturbance

Negative Feedback

Stabilizing and it counteracts deviation

Positive Feedback

Destabilizing and tend to amplify changes and drive system towards the tipping point

Resilience

Ability of a system it return to its initial state after a disturbance

Factors Affecting Resilience

Diversity / Biodiversity / Size of Ecosystem / Speed of Reproduction Process

Ecological Tipping Point

When an ecosystem experiences a shift to a new state in which there are significant changes to its biodiversity. E.G = lake eutrophication

Sustainability

Use and management of resources that allows full natural replacement of the resources exploited and full recovery of the ecosystems affected by their extraction and use

Natural Capital

Natural resources that can produce a sustainable natural income of goods or services

Natural Income

Yield obtained from natural resources

Indicators of Sustainability

Biodiversity / Pollution / Population / Climate

Environmental Impact Assessments

Incorporate baseline studies before a development project is undertaken. They assess the environmental, social and economic impacts of the project, prediction and evaluating possible impact and suggesting mitigation strategies for the project.

Ecological Footprint

Area of land and water required to sustainably provide all resources at the rate at which they are being consumed by a given population

Pollution

The addition of a substance or an agent to an environment by human activity, at a rate greater than that at which it can be rendered harmless by the environment.

Primary Pollutants

Active on emission

Secondary Pollutants

Formed by primary pollutants undergoing physical or chemical changes

Non-Point Source Pollution

Release of pollutants from numerous, widely dispersed origins

Point Source Pollution

Release of pollutants from a single, clearly identifiable site

Persistent Organic Pollutant

Resistant to breaking down and remain active in the environment for a long time

Biodegradable Pollutant

Don't persist in the environment and break down quickly

Acute Pollution

When large amounts of a pollutant are released causing a lot of harm

Chronic Pollution

Results from the long term release of a pollutant but in small amount

Direct Measurements of Pollution

Acidity of rain water / amount of gas in the atmosphere / amount of nitrates in soil or water

Indirect Measurements of Pollution

Measuring abiotic factors that change as a result of the pollutant

Pollution Management Strategies

Changing human activity / Regulating or preventing the release of the pollutant / Working to clean up or restore damaged ecosystems

Ecosystem

Made up of the organisms and physical environment and the interactions between living and non-living components within them

Species

Group of organisms sharing common characteristics that interbreed and produce fertile offspring

Population

Group of organisms of the same species living in the same area at the same time

Habitat

Environment in which a species normally lies.

Factors Affecting Population Density

Natality / Mortality / Migration

Niche

Describes the particular set of abiotic and biotic conditions and resources to which an organism responds

Fundamental Niche

Describes the full range of conditions and resources in which a species can survive

Realized Niche

Describes the actual conditions and resources in which a species can survive

Limiting Factors

Factors that restrict growth of a community, population or organism

Carrying Capacity

Maximum number of species that can be sustainably supported by a given area

Competition

All the organisms in any ecosystem have some effect on every other organism in that ecosystem

Intraspecific Competition

Competition between members of the same species

Interspecific Competition

Competition between members of different species

Principle of Competitive Exclusion

When one species totally out-competes another

Competition + Carrying Capacity

Competition reduces the carrying capacity of each competing species

Predation

The consumption of one organism by another

Herbivory

An animal eating a green plant

Parasitism

When one species lives in or on another gaining its food from it

Mutualism

Relationship between two or more species in which all benefit and none suffer.

Exponential Growth

When there are no limiting factors slowing growth

S-Curves

Start with exponential growth and then stabilises at the carrying capacity

J-Curves

Shows a 'boom and bust' pattern - Grows exponentially at first and then suddenly collapses

Community

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

Respiration

The conversion of organic matter into carbon dioxide and water in all living organisms, releasing energy

Aerobic Respiration

Energy is released and used and the waste products are carbon dioxide and water

Photosynthesis

Process by which green plants make their own food from water and carbon dioxide using energy from sunlight

Compensation Point

Where the rates of photosynthesis and respiration are equal and there is no net release of either oxygen or carbon dioxide

Trophic Level

Position that an organism occupies in a food chain

Food Chain

Flow of energy from one organism to the next

Producers

Make their own food from carbon dioxide and water using sunlight or from other simple compounds

Consumers

Feed on producers and other consumers to obtain energy

Limitations to Food Chains

Only illustrate direct feeding relationships between one organism and another / doesn't show feeding relationships at different trophic levels

Pyramids

Graphical models of differences between amounts of living material stored at each trophic level.

Advantages of Pyramids

Allow easy examination of energy transfers and losses / Gives us an idea of what feeds on what

Pyramid of Numbers

Shows the number of organisms at each trophic level in a food chain at one time - number per unit area

Advantages of Pyramids of Numbers

Simple, easy method of giving an overview / good at comparing changes in population numbers with time or season

Disadvantages of Pyramids of Numbers

All organisms are included regardless of their size / doesn't allow for juveniles / numbers too large to represent accurately

Pyramid of Biomass

Shows the biomass at each trophic level - mass per unit area

Advantages of Pyramids of Biomass

Overcomes some of the problems of pyramids of numbers

Disadvantages of Pyramids of Biomass

Only uses samples from populations / organisms must be killed to measure biomass / time of year measured affects results

Pyramid of Productivity

Shows the rate of flow of energy or biomass through each trophic level

Advantages of Pyramids of Productivity

Most accurate system / allows comparison of ecosystems based on energy flows / pyramids are not inverted

Disadvantages of Pyramids of Productivity

Very difficult and complex to collect energy data / still problem of assigning a species to a particular trophic level when they may be omnivorous

Bioaccumulation

The build up of persistent / non-biodegradable pollutants within an organism because they can't be broken down

Biomagnification

The increase in concentration of persistent or non-biodegradable pollutants along a food chain

Top Carnivores

Always vulnerable to the effects of changes further down a food chain / vulnerable due to the loss of energy from each trophic level

Trophic Efficiency

10% in most food chains

Solar Radiation

Made up of visible wavelengths and those wavelengths that humans can't see

Most Solar Radiation

Isn't used to power living systems as it is reflected from soil, water or vegetation or absorbed and re-radiated as heat

Productivity

Conversion of energy into biomass over a given period of time

Gross Productivity

Total gain in energy of biomass per unit area per unit time

Net Productivity

Gain in energy of biomass per unit area per unit time that remains after deductions due to respiration

Gross Primary Productivity

Total gain in energy or biomass per unit area per unit time by green plants

Net Primary Productivity

Total gain in energy or biomass per unit area per unit time by green plants after allowing for losses to respiration / NPP = GPP - R

Amount of Biomass Produced

Varies on space and temperature

Net Secondary Productivity

Total gain in energy or biomass per unit time by consumers after allowing for losses to respiration / NSP = GSP - R

Gross Secondary Productivity

Total energy or biomass assimilated by consumers / GSP = food eaten - faecal loss

Amount of Biomass Assimilated

Carnivores - assimilated 80% of the energy in their diets

Herbivores - assimilate about 40% of their diet

Carbon Cycle

Carbon is stored in carbon sinks - fossilized life forms, oceans