Environmental systems and societies (IB)
Terms in this set (178)
Topic 1 - Systems and Models
an entity with at least two components that are linked and interact in some way. E.g Carbon cycle, Nitrogen cycle, Water Cycle
Name the 3 types of Systems and describe them
Open - Energy and matter can enter or leave systems. E.g Human Body
Closed - Energy can but matter cannot leave. E.g Earth with the exception of space travel.
Isolated - Do not allow either to enter. Only e.g would be the entire universe.
Transfer vs Transformation
Matter when transformed changes state vs. when transfered is moved from place to place.
Matter vs Energy
Matter is anything that takes up space and is normally made up of atoms.
Energy is the ability to do work and effect either the transformation(change) or transfer(movement) of matter. E.g Heat, light, movement(kinetic)
First Law of Thermodynamics
Energy can neither be created nor destroyed.
Second Law of Thermodynamics
In an isolated system the total amount of entropy will tend to increase. E.g Earths system is not isolated, it imports energy and uses this to work against the entropy law, allowing organisms/ecosystems to build up their order and complexity with constant energy from the sun. If it were isolated, there would be no sunlight entering the Earth increasing entropy and resulting in the breakdown of all chemical structures through death/decay.
A condition where forces/quantities are in balance.
e.g ecosystems show resilience to change, after a disturbance the system has uses negative feedback to return to the same state of equilibrium.
An initial change in the system leads to a cycle that returns to and reduces that change. Important in maintaining a stable equilibrium in a system. E.g Temperature regulation (cooling systems in our bodies)
Increase in predator -> decrease in prey -> decrease in predator
An initial change in the system triggering a cycle that returns to and amplifies the change moving away from equilibrium to a new state. E.g climate change and succession.
Increase in primary production(plant growth) -> increase in falling leaves -> increase in soil organic matter ->increase in nutrients -> increase in primary production
Refers to the reflectivity of a surface; black is lowest, white is highest. E.g the melting of polar ice caps leads to a decrease in global albedo (less reflective white surfaces around to reflect back the light). Leading to an increase in warming as the ground absorbs the heat further decreasing ice cover as the waters are warmer.
His model "daisyworld" shows populations of white/black daisies regulating temperature on a barren planet. White daisies keep cool in hot temperatures surviving and reproducing -> white population increase -> albedo increase -> temperature cools down -> black daisies absorb heat to stay warm, survive and reproduce -> black population grows -> temperature rises again.
Topic 2 - Ecosystems
complex systems that interact within each other for e.g living with non living components of a defined unit.
science of the relationship between living and non living environment.
Group of organisms who interbreed and produce fertile offspring
Group of organisms of the same species living in the same area at the same time and are capable of interbreeding.
Environment in which a species lives
Species' share of a habitat and it's resources.
Group of populations living and interacting with each other in a common habitat.
Community of interdependent organisms and the physical environment they inhabit.
1st Trophic Level
Autotroph - primary producer
2nd Trophic Level onwards
Heterotroph - Primary to Tertiary consumers .
Position that an organism occupies in a food chain.
Heterotrophic organisms that consume dead organic matter by ingestion e.g earth worms.
Strangling Fig -> Wild Boar -> Leopard Cat -> Indochinese Tiger
(S.E Asia forest with 4 trophic levels)
Expect that only 10% of energy in one trophic level will pass on to the next.
Ecological Efficiency (percentage)
(Amount in the higher trophic level/lower level) x 100
1. Biomass is not equivalent to energy
2. Does not show energy flow
Application of pyramids
The sustainable population that could be supported in a given area by feeding at a lower trophic level is far greater than that which could be supported by eating at a higher trophic level.
Biotic factors in population - Competition
Competition for space, light, mates, food (finite resources) -> limiting factors. Can be intraspecific or interspecific. E.g Otter vs North American Mink in the UK.
Biotic factors - Parasitism
leeches or mosquitos
Biotic factors - Herbivory
consumption of autotrophs by primary consumers e.g leaf monkeys
Biotic factors - Predation
consumption of primary consumer by a secondary consumer or higher. E.g Snowshoe hare -> Lynx
Abiotic factors - Terrestrial
-Soil (successional stage, pH, % water content)
-Aspect/Slope (angle and direction of slope influencing drainage etc)
-Elevation (height above sea level) (m)
Abiotic factors - Freshwater
-Flow Rate (m/s)
Abiotic factors - Marine
-Dissolved oxygen (mg/l)
-Wave Action (m/s)
A min and max tolerance for abiotic conditions e.g temperature
Estimating Abundance of organisms - Quadrat
(No. of occurrences in quadrats/No. of quadrats taken) x 100 = frequency percentage
Direct modes of estimating abundance of animals
Indirect - Lincoln Index
N = (M x n)/r
N - Total number of population
M - Total number caught in first sample (including r)
n - Total number caught in the second sample (includes r)
r - total number recaptured in second sample
Diversity - Simpson's Index
D = (N(N-1))/sum of n(n-1)
N - total number of organisms in community
n - total number of an individual species
Lower the value of D the less diversity there is.
Insolation & Latitude
Light arriving at the equator is straight on and more concentrated in one place compared to light at either pole.
Very little plant life, no trees as soil water is a permafrost. Very low rainfall. Cold, dry due to humidity. Highest latitudes.
Only specially adapted plants such as desrt cacti survive, extreme lack of rain/water. Arid climate. 20/30 degrees of either side of the equator.
Thick canopies of trees (emergent), abundance of animals, a lot of rainfall, no dry season. Rainful is greater than transpiration. At equator.
RATE of growth of an organism, population, community or trophic level. Production of a defined group over time. Often measured in biomass.
occurs before respiration
GP - R
GPP - R = NPP
GSP = (Food eaten - Feces lost) - R
GSP - R
No. of organisms of a species in a defined area.
Rate of population growth
(BR + I) - (DR + E) -> expressed as a percentage
If there are predators, parasites, disease, absence of food, water, shelter then populations could go into decline.
The natural limit to any population in a defined area terming the environments capacity to sustainably support its population.
Density dependent factors
Intraspecific competition for food, space, water, predation. These factors act as negative feedback by regulating populations at carrying capacities.
Density independent factors
Influences population irrespective of density. Typically abiotic and to do with the environment such as floors, droughts, earthquakes.
Factors arising from within the population such as intraspecific competition for food, territory etc
parasites, predation, interspecific competition(inter-species)
Mostly seen with K strategists; at the start there are limiting factors but then there is exponential growth and fluctuation around the carrying capacity because of negative feedback mechanisms.
R strategists; The curve goes well beyond carrying capacity till it crashes and exponentially decreases. (Boom and bust population growth).
K vs R
K; small numbers of offspring, large amount of time invested in their parental care.
R; large amount of offspring, on their own immediately after birth.
Environments changing over time making adaptions to species etc Positive feedbacks drive this forward.
mt vesuvious, rome example!
Topic 3 - Human Population Growth
study of populations is called demography.
"The Population Explosion"
Rapid exponential growth of population this century compared to slow growth during rest of humanity.
Crude Birth Rate
Annual no. of births per 1000.
Crude Death Rate
Annual no. of deaths per 1000.
Reproductive potential of the population.
Fertility Rate: Ave no. of births per woman of the child bearing age range.
Total Fertility Rate
Ave no. of children a woman has in her lifetime. E.g in 2009; Nigeria was 7.07 per woman.
No. of years it would take a population to double. Doubling time = 70/natural increase rate
Natural Increase Rate
Rate of growth in human populations (always divide by 10 as CR & CD are measured per 1000) and you want a percentage (out of 100).
(CBR-CDR)/10 = NI
Most of population prediction uncertainty lies in crude birth rates which varies due to several socio-economic factors.
DTM Stage 1: High Stationary
-Standard concave pyramid shape
-Little or no family planning
-Large families for agricultural work
E.g tribal people in Amazon or New Guinea
DTM Stage 2: Early Expanding
-Improved medical care, food security and irrigation.
-Pyramid is still wide but less concave as height grows (people live longer)
-Decrease in child mortality
-Increased life expectancy
DTM Stage 3: Late Expanding
-Rapid Growth slow towards end of stage
-Pyramid becomes convex
-urbanization leads to falling fertility
-industrialization reduces need for labour
-family planning improves
DTM Stage 4: Low Stationary
-High stable or declining
-Low fluctuating birth rate
-Low stable death rate
-need for small families arises
-emancipation of women(education etc.)
-Increasing value placed on consumption
-Pyramid becomes weird and inverted
1. Renewable e.g food, timber, stable climate, air, water
2. Replenish-able: Water stores, groundwater or surface water, soil nitrate fixed by lightning, stratospheric ozone layer.
3.Non-renewable: Fossil fuels, tin ore, land,
Living within the natural income without reducing natural capital.
Sustainable yield: rate of increase in natural capital.
meeting the needs of the present without compromising the future.
Agenda 21: global agreement towards this in the 21st century.
Factors that affect energy sources adopted by different societies
Availability: Resources within or near to a country are better than those far away.
Economic: Costs like capital costs and running costs, high capital with low running may not be affordable to poorer countries.
Cultural: Energy forms that have been used previously are often preferred within cultures. "Cultural Inertia" - resistance to change of habit
Environmental: Legislation, education and dominant environmental value systems may influence countries.
Tech: Higher tech may require expensive training of labour, importing of foreign workers.
Renewable resources such as plants, animals, and soil provided by natural capital.
Demand side management
To meet increased demand or reduce demand through an increased efficiency of use. Promoting energy conservation, improved grid design, buying back surplus from buildings that generate their own electricity.
Fuel type: Oil
A: versatile, transportable, high energy content against mass
D: rising costs, pollutants: nitrogen oxides, c02, location of resources are only in a few nations, peak production is near
Fuel type: natural gas
A: Versatile, cheaper than oil, fair energy content vs mass, low emissions when combusted
D: Inflammable, non renewable, impact of mining and pipelines
Fuel type: coal
A: will last longer than oil, cheaper than oil, electric power generation can be built near coal fields to give cheap power
D: Pollutants from combustion; sulphur dioxide and c02, mining can be difficult, dangerous and polluting, non renewable, bulky, hard to transport
Fuel type: Solar
A: Continuous supply, can be used directly for cooking, heating, houses etc
D: Large seasonal variations at high latitudes, large areas needed, most expensive option
Fuel type: Biofuels
A: traditional, c02 neutral, can provide habitat for wildlife,
D: Destruction of natural habitats, irrigation demands, can compete with food supply
Fuel type: Wind
A: Renewable, low pollution(manufacturing only), similar costs to thermal
D: Visual and noise pollution, hazardous to animals, only for windy areas
Fuel type: Hydro electric
A: Low pollution, renewable, provides reservoir water for fishing, recreation and irrigation.
D: Depends on adequate rainfall, river flow, destroys existing natural ecosystems by submerging them
Fuel type: Nuclear
A: Does not produce c02, requires small quantities, can produce large amounts of electricity
D: Limited supplies e.g uranium, radioactive wastes pollute environment for long times, risk of meltdown
Silt - clay - sand
caused by livestock, damages physical structure by trampling and can remove vegetation cover. Leads to an increase in soil erosion by wind or water and desertification.
Removal of forest cover removes protection of the canopies and roots, increasing in soil erosion.
Most agricultural practices remove upper soil horizons (o and a) which means the planting occurs in B.
Poor techniques lead to soil salinization from evaporating water. Causing a stress for plants and damages agricultural productivity or lead to crop failure.
Wind/water remove upper layers of soil removing organic material, minerals and nutrients impacting water quality and causing flooding.
Can cause crop failure and thus lead to malnutrition and famine.
Soil conservation methods:
Terracing, contour ploughing: reduces surface run off
Wind breaks: prevent wind erosion
Strip cultivation: mixed cropping in a systematic series of bands as a barrier to water/wind. Staggered harvest reduces the amount of exposed soil.
Improved irrigation: Trickle dip -> slow releases of water from under surface reducing loss of water by evaporation or salinization.
Global food supply issues
MEDC'S -suffer from over feeding
LEDC'S -suffer from malnutrition, famines
Terrestrial - producers, herbivorous foods
Aquatic - carnivorous e.g fish
Produces good quality efficiently and inexpensively.
Minimizes resource use.
Protects soil, water, air quality.
Preserves and enhances biodiversity and landscape quality.
Oceans and seas 97.2
Glaciers (most of it is here)
Rivers / Streams
Role of Water Cycle
movement of water between stores connects soils, agriculture and water resources.
Precipitation -> Interception(by veg e.g) -> Surface water ->(infiltration) Soil Water -> Groundwater (storage of water in rocks)-> rivers -> oceans
Global Carrying Capacity
Maximum number of people that can be sustainably supported by a given environment.
population grows geometrically whereas food grows arithmetically leading to famines.
Counter argument of technology and intensification(essentially increasing carrying capacity along with energy conservation and recycling and demand management)
Refers to the impact of a given population on nature. It is a way of estimating how many resources each person would need to maintain his or her present lifestyle. (1/carrying capacity)
Topic 4 - Biodiversity and Conservation
The amount of biological diversity or living diversity per unit area. (species, habitat and genetic)
Number of species and their abundance
Development of new species
speciation (occurs due to isolation of individuals in a new situation)
evolutionary. "The best suited for the niche" of the environment.
-genetic diversity ; variation
-natural variation causes some to be fitter than others
-fitter ones reproduce more successfully
-offspring of fitter ones inherit the "fit" genes
Number of continents
directly corresponds to number of species.
Resilience to move the system to a new position
How well the system can move back to its starting position
Stable only within a narrow range of environmental conditions
Greater habitat diversity leads to greater species and genetic diversity.
A greater variety of niches.
Natural threats to biodiversity
Natural disasters (mass extinctions)
Replacement evolution (older ancestral species are replaced by newer versions)
Meteorite impact, volcanic eruptions, droughts, ice ages, climate change and sea level rise, genetic inferiority.
Human Threat to biodiversity
Agriculture-Habitat destruction-Invasive non native species-Pollution-Population-Over harvesting(beyond sustainable yields)
Factors for extinction
Low numbers, specialized niche environment, reproduction potential(K are more prone to extinction as they reproduce slower and fewer), behavior (sensitive to disturbance etc), trophic level(high - more as they are at low density and require a lot of space)
Indochinese tiger - panthera tigris
Ways to conserve
Use of media/political influence
Nature reserve design
Big and closer together is good.
Species based conservation
focus on single species and prevent it form extinction.
-captive breeding and reintroductions (arabian oryx)
-attempts to breed larger animals may be difficult and could result in reduced genetic diversity (south china tiger)
-sperm banks,artificial insemination
-botanic garden and seed banks
-aesthetic vs. ecological value - who would save?
Topic 5 - Pollution
Release into the environment of a harmful substance by human activity.
pollution released from a single point source
-easier to monitor
-easier to control
-easily established responsibility
-localized effects can be managed easier than global
Non point source
released from diffuse sources e.g pesticides from fields or single sources such as car exhausts
-emission control requires widespread changes
-responsibility is shared amongst many - greater effort to enforce change
-effects are wider spread over a wider area
-monitoring is too complicated
Sources of Pollutants
Domestic, industrial, agricultural.
fossil fuels - transport and electricity generation
Types of pollutants
persistent vs biodegradable
persistent - pesticides, heavy metals dont break down easy in organism bodies or environemtn.
biodegradable - oil/sewage breaks easy by bacteria etc.
builds up in food chain and is very toxic to consumers at the end. Minamata bay, An agri-chemical company released effluent into the bay -> mercury settled on sea bed ->Bacteria-> shellfish & fish -> humans & cats -> 50 people died before problem got controlled.
salination, pesticides, fertilizers, manure, silage
toxic spills, nuclear waste, solid waste
sewage, solid waste (garbage)
Road run off (contaminates groundwater and coastal waters)
Sulphur dioxide(acid rain), nitrogen oxides(acid rain + eutrophication), particulates (bronchitis)
CAUSE-alternative technologies, life styles, reduce/reuse/recycle
RELEASE AND TRANSFER-setting standards, cleaning up emissions
EFFECTS-removing pollutant from ecosystem, replanting or restocking (animals), habitat restoration
Human factors influencing pollution management
cultural, political, economic factors all influence the choice of pollution management strategy and its effective implementation.
cultural - dominant attitudes towards environment, accepted ethics of that society
political - legal framework for regulation
economic - what's cheaper?
Rapid algal growth (algal bloom) caused by an excess of nitrogen & phosphorus, blocks sunlight, causing the death/decomposition of aquatic plants, decreasing dissolved oxygen (DO), suffocating fish.
Impacts of eutrophication
-death of fish that require high O2 levels
-poisoning of organisms due to toxic algal blooms
-turbidity of water increases leading to death of organisms that reside low in lakes and need sunlight.
-declines in biodiversity and food chain length.
-decline in fisheries and loss of water resources for people, livestock, recreation.
-bad smells from decomposing matter impacting tourism and recreation
Movement of nutrients and sediments in landscape
water carries nutrients:
-surface run off, groundwater
nitrates are water soluble they can do either ^
phosphates are not so they enter through surface run off or through sewage pollution.
-contour ploughing to reduce run off
-time it to avoid rain
-phosphate free washing powder
-dry composting toilets
release and transfer: agriculture
-buffer zones around streams
-light tractors with broader wheels reduce soil compaction so decreasing run off
release and transfer: domestic
-phosphate strippers (remove phosphate in swage works)
pumping mud from lake bed
use of decomposing barley straw bales to inhibit algae
Waste causes level strategies:
release and transfer
reduce, reuse, recycle, compost
incineration, landfill sites, composting
found in the stratosphere. Formed when UV light collides with O2. O2 is split from diatomic to monatomic which reacts with other chemicals.
It filters out UV light which has a negative impact on species that have evolved under ozone protection.
reduces primary production and therefore total productivity
Depletion of stratospheric ozone
ODS' - halogenated organic gasses such as CFC's and HCFC's. They're used in propellants in aerosols, coolants for refrigerators and air conditioning, fire extinguishers. Highly persistent (not biodegradable) in the environment. These gasses travel to the stratosphere and react with ozone disrupting equilibrium. A decline in total ozone is most severe in polar regions.
Ozone management strategies
refrigerants - greenfreeze technology (propane/butane)
recycle old cfc coolants
Bad! in contact with living things it causes lung damage and irritates the eyes, damages plants and corrodes fabric. Powerful oxidant and reacts corrosively.
Tropospheric ozone is a major component of this. Hydrocarbons from car exhausts enter reaction series producing more dangerous chemicals such as methane which then reacts to form strong toxic oxidants. Smogs are when weather is combined with pollution. Requires sunny windless conditions so primary pollutants are not dispersed and sunlight drives the reactions. More in urban areas as the lack of vegetation and water absorbs more heat.
Smog prevention: public transport, catalytic converters, reduce consumption of electricity, titanium dioxide coated concrete converts NOx to nitrates.
common cause: fossil fuel combustion that leads to sulphur dioxide and nitrogen oxides forming.
they form atmospheric sulphates and nitrates which can be deposited and cause acidification and eutrophication of ecosystems.
Effects of acid deposition
soil -fungi cant handle low pH, metals reduce population of microorganisms, accelerated leaching of calcium and magnesium
water -damage exoskeleton of crustaceans such as crabs, Al ions cause build up of mucus on fish gills and death from lack of oxygen entering gills, more eutrophic waters (more nitrate)
living organisms -damages tree leaves, trees uptake toxic ions from soil, lack of Ca and Mg leads to reduced ability to carry out photosynthesis.
acidified deposition can travel easily across national boundaries from one nation to another.
acid pollutants that reach the earth in precipitation. Sulphur dioxide and nitrogen oxides combine with any form of atmospheric water to form acid precipitation, e.g rain, containing sulphuric and nitric acids. -> acid rain.
Buffering capacities of ecosystems
capacity to absorb acid deposition.
chalk and limestone areas have the ability to buffer acidity as CaCarbonate neutralizes the acid.
Management of acid deposition
Alternative energy sources, divert the demand, liming of soils, lime bombing, lime scrubbers, cleaner fuels such as low sulphur coal
Carbon dioxide, methane, water vapor, Nitrogen oxides, CFCS, HCFC's
They trap longer wavelengths of UV light such as infra red that are radiated from the earth. This regulates earths temperature keeping conditions warmer than without the effect and more hospitable to life.
Source of C02
Combustion, decomposition and respiration
Anaerobic decomposition in rice fields and landfill, cows and stores under the arctic permafrost and oceans.
Internal combustion engines
Fridge coolants and aerosol cans
Increase in greenhouse gas levels released into the atmosphere ...
increase in greenhouse effect, increased heating, change in global average temperature
consequences of climate change
-decrease in sea ice cover and permafrost -> increase in methane released from arctic seas and soils -> further increase in GHG levels as well as abedo decreases meaning earth gets even warmer as the heat is no longer reflected back but absorbed in.
-increase in droughts
-biomes shift in latitude and altitude
-crop growing regions shift
-coastal areas flood due to thermal expansion of oceans and land-based ice caps melting
-tropical diseases spread faster at hotter temperatures
Increase in atmospheric pollution by sulphates and particulates was reducing the amount of light energy reaching the ground, reducing evaporation rates ultimately reducing the amount of pollutants entering the atmosphere and thus reducing the impacts of warming.
-Cap and Trade
-Solar radiation management
-Carbon dioxide reduction
-Build design (acs, aerosols, buildings etc)
-coastal management (improved sea defenses)
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