ess unit 1 - foundations of ess

open system

exchanges matter and energy with its surroundings e.g. forest ecosystem

closed system

exchange energy but not matter, extremely rare in nature e.g. the carbon cycle

isolated system

exchange neither energy nor matter, do not exist naturally e.g. the entire universe

steady state equilibrium

characteristic of open system where there are continuous input and outputs of energy and matter but the system remains in the same state

tipping points with example

minimum amount of change within a system that will destabilise it, causing it to reach a new equilibrium e.g. coral reef death

resilience of a system

its tendency to avoid tipping points and maintain stability

negative feedback

no changes occur, same state of equilibrium is maintained through self regulation

positive feedback

changes occur, shift in equilibrium through permanent changes

energy transfers with example

the flow of energy that doesn’t involve a change in state e.g. rain running off of a mountain into a river

energy transformations with 2 examples

the flow of energy that involves a change in form and state e.g. energy to matter (photosynthesis), light to heat

first law of thermodynamics with example

energy cannot be created or destroyed e.g. during photosynthesis light energy is converted into stored chemical energy

second law of thermodynamics

the entropy of a system not in equilibrium will tend to increase over time

entropy

a measure of disorder of a system, refers to the spreading out or dispersal of energy

example of steady state equilibrium

a population of ants may stay the same but individual organisms are born and die, if the birth and death rates are the same there is no change in population size

static equilibrium with example

there is no change over time, only occurs in non-living systems e.g. a pile of rocks

stable equilibrium

system will return to the same equilibrium after a disturbance

unstable equilibrium

system shifts to a new equilibrium after a disturbance

negative feedback example

there is a good supply of food in an area, number of grazers increases through migration, grassland becomes overgrazed, decreased food supply which limits the number of grazers so they migrate or die, grassland is large again

positive feedback example

rising global temperatures, ice caps melt, decreases Albedo, more solar radiation is absorbed, rising global temperatures

environmental value systems

a particular worldview set of values that shape the way groups perceive environmental issues

ecocentric beliefs

• see themselves as equal to other living things

• goal is sustainability

• believe in interdependence

• aim to spread awareness

anthropocentric beliefs

• believe humans must sustainably manage the global system through environmental regulation

• environmental managers such as NGOs, politicians

technocentric beliefs

• believe technological development can provide solutions to environmental issues

• value the understanding of natural systems

• counter resource depletion with resource replacement

factors that affect ecosystem resilience

• complexity (more is better)

• size (larger is better)

• biodiversity

• genetic diversity

• stable climate

• rate of reproduction (faster is better)

sustainability

the 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

• ability to meet the current generations needs without harming the future generations socially, economically and environmentally

natural capital

natural resources that can produce a sustainable natural income of goods and services e.g. trees, soil, water

natural income

the monetary value and yield of natural capital

3 groups of natural capital

renewable, non-renewable and replenishable resources

ecological footprint

area of land expressed in global hectares (GHA) with the resources required to meet the needs of an individual or society

type of pollutants

• matter (gases, liquid or solids that are organic or inorganic)

• energy (sound, light, heat)

• living organisms (invasive species)

primary pollutants with example

are active on emission e.g. carbon monoxide from fossil fuels

secondary pollutants with example

formed by primary pollutants undergoing physical or chemical changes e.g. sulphuric acid forms when sulphur trioxide reacts with water

non-point source pollution with example

release of pollutants from numerous sources that cannot be easily identified and are harder to address e.g. air pollution, rainwater

point source pollution with examples

release of pollutants from a clearly identifiable site and is easier to manage e.g. a factory chimney, sewage pipes

pollution management model

changing human activity which produces pollutant → controlling the release of pollutant → working to clean-up and restore damaged ecosystems to reduce impact

two types of ecocentrists

• soft ecologists → self reliant

• deep ecologists → who value nature above humanity

two types of technocentrists

• cornucopians → who believe that we can solve any environmental issues with technology

• environmental managers → who believe we need governments to protect the environment

bioaccumulation

the build up of a pollutant within an organism or trophic level because it cannot be broken down

biomagnification

the increase in concentration of persistent pollutants along a food chain