Systems and models Flashcards
What is a system?
A system is an assemblage of parts, working together, forming a functional whole
What is a transfer?
Something moving from one place to another. It does not change its type (i.e. water flowing down a mountain)
What is a transformation?
When things change form (i.e. liquid to a gas)
When the inputs = outputs, the system is in …………
Equilibrium
What is an open system?
A system that exchanges energy and matter with its environment
What is a closed system?
A system that exchanges energy but NOT MATTER with its environment
What is an isolated system?
A system that exchanges neither energy nor matter with its environment
What is a model? Why do we use it? Give one example
A model is a simplified version of a real system. We use it to understand and predict how a system will work and change. One example is with the weather and using a model to predict it
State 3 ways energy may flow through a system as a transfer, with examples
- heat -> respiration
- electrical -> in pylon wires
- chemical -> food in your gut
Using a plant as an example system, name the inputs, output, energy and matter transfers, matter and energy transformation
inputs: water, sunlight, CO2
outputs: oxygen, glucose
matter and energy transfer: water, light and chemical energy
matter and energy transformation: photosynthesis, respiration
What is the first law of thermodynamics?
Energy is never created or destroyed, only changed from one form to another
What is the second law of thermodynamics?
Entropy in a system always increases
What is entropy?
A measure of chaos and disorder in a system
What is low grade energy, and give an example?
Energy we can not use
example: heat
If there are more steps in a system, what happens to the entropy?
It increases
Compare the energy efficiency of herbivores and carnivores (entropy)
Their entropy is the same, as they both lose energy in metabolic processes (running from a predator and predators running after prey)
Explain why heat is an example of energy characterised by high entropy?
Because high entropy means more chaos in a system, therefore there is more low-grade energy (heat) lost to the environment
What happens to entropy when a creature dies?
Entropy increases because all their energy is converted into heat (low-grade energy)
Explain why an organism ‘surviving against the odds’ goes against the second law of thermodynamics
An organism going ‘against the odds’ is going against high entropy so has a less chance of survival
Explain why the entropy of a living system stays low while the entropy of the environment increases
The environment is always gaining low-grade energy from other systems and organisms, therefore there is a high entropy, whereas a living system can replenish its energy
Explain why a high level of complexity in a food web is more likely to provide a stable system
As one organism goes, another organism can take its role, therefore there is more stability
What does a stable equilibrium graph look like?
The line returns to the original equilibrium after the disturbance
What does a static equilibrium graph look like?
There is no change or disturbance over time
What does an unstable equilibrium graph look like?
Returns to a new equilibrium after the disturbance
What does a steady-state equilibrium graph look like?
The system is more or less constant, but has small fluctuations
Describe the role of any 2 names historical influences in the environmental movement [3]
(remember a historical influence can be a person, organisation or event)
Some examples (only need 2):
- Greenpeace (1970) -
Took direct action to prevent whale killings
- Chernobyl nuclear meltdown (1986)
reinforced negative perception of nuclear power in society - Rachel Carson -her book: A silent spring
raised awareness on the threat of the pesticide DDT, as a POP, to organisms high up the food chain - Minimata disease -
Raised awareness on the regulation of effluents from factories and increased legislation
What is feedback?
Feedback occurs when the output of a system influences the inputs and hence affects the state of the system
What is positive feedback? is it usually a good or bad thing?
positive feedback changes a system to a new state. It is usually a bad thing
What is negative feedback? is it usually a good or bad thing?
negative feedback returns a system to its original state. It is usually a good thing
Give 2 examples of positive feedback
- Arctic ice melts reducing albedo [1] less incoming solar radiation is reflected [1] and this increases further melting of Arctic ice [1].
- Increased temperatures result in greater evaporation [1] more water vapour in the atmosphere acting as a greenhouse gas [1] leads to increased temperature [1].
Give 2 examples of negative feedback
- CO2 levels rise, meaning the temperature of the earth rises. As the earth warms, the rate of photosynthesis increases, therefore more CO2 is removed from the atmosphere, reducing global temperatures
- As the Earth warms, there are higher rates of evaporation. This produces more clouds. Clouds increase albedo, reflecting more light away from the earth. The temperature falls and evaporation rates fall
What is albedo?
The reflectiveness of the Earth’s surface
What is anoxic?
lack or without oxygen
What is meant by ‘Resilience’?
The ability of a system to ‘bounce back’ after a disturbance
What is meant by ‘tipping point’?
When a system is pushed past a point, where it cannot return to its original state, even if the main cause is removed
What is sustainability?
The use and management of resources that allow full natural replacement of the resources exploited and full of the ecosystems affected by their extraction and use
What is ecological overshoot?
The maximum level of sustainable resource exploitation
What is natural capital?
the goods and services that the environment provides humans in order to provide natural income
What is natural income?
The annual yield of goods and services
What is an example of natural capital and income?
Natural capital - forest
natural income - timber
What is an environmental impact assessment?
a tool used to assess the significant effects of a project or development proposal on the environment
What should the report provide to the public?
A non-technical summary of the proposal and its impacts for the public and media
What is an ecological footprint?
the impact of a person or community on the environment, expressed as the amount of land required to sustain their use of natural resources.
If the environmental footprint is greater than the area available to a population, is this sustainable or unsustainable?
unsustainable
What is an ecological debtor?
When are countries ecological footprint exceeds the area available for natural resources or living
What is an ecological creditor?
When a country’s ecological footprint is less than the area available for natural resources for living
What do you ecological footprints depend on?
Ecological footprints depend on:
- population size (how many people and how much land each one uses)
- consumption per capita
How do you calculate ecological footprints? (4)
- Fossil fuels and energy consumption
- Land available for food
- forest products
- land required for towns roads and factories
Give three advantages of ecological footprints.
- They are an indicator of sustainability
- they are a clear indicator of resource injustice
- they can allow for national footprint comparisons
Give three disadvantages of ecological footprints
- It ignores the effects of air pollution or toxins
- it does not show denser or shallower areas - it is an average
- it does not capture other environmental strains
What can be done to reduce an ecological footprint by a country? (3)
- they can organise recycling programs
- they can limit the amount of fishing and hunting
- they can limit the amount of pollution and carbon emissions in factories
- they can establish laws or fines protecting the environment and conserving resources
- they can promote the sale of environmentally friendly products
- they can create more national parks and resorts
What is pollution?
Pollution is the addition of a substance or an agent to an environment by human activities at a rate greater than at which it can be rendered harmless
What can pollutants be in the form of?
- matter organic (containing carbon atoms) or inorganic
- energy (e.g. noise pollution)
- living organisms (e.g. invasive species like Japanese knotweed)
What are primary pollutants and name three examples
Primary pollutants are substances or agents that are emitted directly and remain unchanged in the atmosphere. 3 examples are:
- carbon dioxide
- sulphur dioxide
- carbon monoxide
What are secondary pollutants and name three examples
Secondary pollutants undergo chemical changes in the environment as a result of reactions among two or more pollutants. 3 examples are:
- sulphur trioxide
- ozone
- nitric acid
What is point source pollution
This is when sources of pollution can be represented as a single point on a map. This is because they can be traced back to the origin. For example: a single waste disposal pipe into a river
Give one advantage of point source pollution
One advantage is it is easier to spot the source of pollution and find out who is causing it so they can be held accountable for
What is non-point source pollution
This is when there are numerous sources from which pollutants originate and enter the environment. For example: gases from vehicles and eutrophication
What’s a disadvantage of non-point source pollution
One disadvantage is that it is difficult to deal with the problem because it is coming from multiple sources
What is acute pollution? give example
Acute pollution is when large amounts of pollution cause lots of disasters for example the Bhopal disaster in 1984
What is chronic pollution? give an example
Chronic pollution is the long-term release of a pollutant but in small amounts for example Beijing’s poor air quality causing respiratory diseases for example asthma
Name three disadvantages of chronic pollution?
- goes unnoticed for a long time
- it is usually harder to clean up
- it spreads widely
What is biological oxygen demand?
It’s the amount of oxygen needed to aerobically breakdown organic materials by decomposers
What is direct pollution? give an example
This is when measurements are taken at the source of the pollution for example the acidity of rainwater
What is indirect pollution? Give an example
This is a way of measuring pollution by seeing how bad its impacts are. One example is the presence or absence of indicator species due to pollution for example: rat-tailed maggots can live and survive in severe pollution
What is human factors affect the approaches of pollution management?
Cultural factors - the readiness of a population to change their lifestyle
Economic factors-the economic development of a country may determine whether they can take a sustainable approach cheers
Political factors-creating and forcing legislations
Name three examples of countries that show different human factors which can affect the successful implementation of pollution management strategies
-Cultural - Scandinavia has adapted to alternate lifestyles
-economic - India does not have enough money for waste and litter management which limits their success
-political- UK for example ULEZ zones and their fines
What are persistent organic pollutants
Persistent organic pollutants are organic compounds that are resistant to environmental degradation through chemical and biological processes
What is biomagnification
This is the accumulation of a toxin by successive trophic levels. Predators will gain higher doses of the persistent organic pollutant from prey
What is bioaccumulation
This is the build-up of a toxin in one living organism
Why does the toxin grow in one living organism
This is because the toxin cannot be broken down or the toxins are taken in faster than they are used
Give one real-life example of when biomagnification was demonstrated
The Minamata disaster
What is DDT
DDT is a toxin that accumulates in the food chain faster than it can be rid off, causing lots of detrimental impacts to the environment and wildlife
What was the DDT originally used for
DDT was first recognised as a useful insecticide in 1939. It was found to be particularly effective against insects which carry disease, especially the mosquitoes which carry malaria
What is an important environmental case against DDT
“Silent Spring “by Rachel Carson in 1962
Why is DDT banned in most countries
DDT is a known carcinogen and this is a main cause of cancer
DDT also affects wildlife for example bald eagles and the thinning of their eggs. this is through biomagnification
It can not be broken down in organisms causing an increase in bioaccumulation
Name three advantages of DDT
-Effective in killing mosquitoes
-reduces malaria
-cheaper
Name three solutions to what you think should be done about the use of DDT and the problem of malaria
(remember that the majority of countries which have a major malaria problem and still use DDT are very poor)
-Vaccines should be distributed to poor countries
-invest in research and sustainable methods of mosquito control
-promoting education and awareness about preventative measures can reduce the spread of malaria
What is carrying capacity
the number of people, animals, or crops which a region can support without environmental degradation.
What is a baseline study
an analysis of the current situation to identify the starting points for a programme or project
What EIA will I reference in a question
Maasvlakte Rotterdam airports and port development
What three issues did the Rotterdam airport and port development EIA encounter
-Land reclamation
-fisheries
-National Conservational areas
What is land reclamation
The gain of land from sea or close to areas
What is one problem they found with land reclamation
Materials had to be transported in from many countries to build up the ports. This increases carbon emissions
Name 4 impacts of land reclamation
-Cargo ships affect marine life
-increased carbon footprint due to an increase in transport distances
-direct impact on human health causing lung and cardiovascular diseases
-the decrease in biodiversity may have a knock-on effect on local fishermen who depend on marine life for income
Why was the commercial fishing industry important to the Netherlands
The Dutch fishing wholesaling industry placed an important part as a trading hub for many EU countries
Name for impacts of the Rotterdam development on commercial fisheries
-With waste from the airport, disease may be inevitable for integral fish for example shellfish
-the introduction of pathways roads and transport routes has damaged the surface of the land and driven away fish into a new habitat
-this may result in reduced catches for the fishermen and affect their income
-it may destroy or damage fishing grounds and habitats and reduce the biodiversity of the area. This may impact food chains and increase the number of endangered species in the area e.g. the northern right whale
Name for management strategies to Rotterdam development used
-It is mandatory for ships to discard the waste products at the port-designated waste reception facilities
-to make sure the ships hand in their waste and effluents all ships must notify the port authority of the waste on board and their capacity for waste storage
-another relevant development is the creation of artificial nesting islands for birds
A marine protected area of 25,000 has been established by the Dutch state where no construction is allowed to occur
