Unit 1
Think about world views.
explain the three world views from Unit 1
Technocentric Worldview: The technocentric view posits that technology can prevent or solve environmental problems. This perspective is rooted in a strong faith in human ingenuity and technological advancement.
Belief: Technocentrists believe that any ecological challenges can be addressed through scientific and technological innovation. They see technology as a means to sustain human life and economic growth without necessarily reducing consumption or waste.
Anthropocentric Worldview: Anthropocentrism places humans at the center of existence, viewing all environmental elements in terms of their value to humanity.
Belief: This perspective varies widely but generally involves managing the environment for human benefit. It can range from conservation efforts aimed at preserving resources for future human use to exploiting natural resources for immediate human gain.
Ecocentric Worldview: Ecocentrism regards the natural environment as the most important component of existence, emphasizing the intrinsic value of all living and non-living elements of the ecosystem.
Belief: Ecocentrists advocate for the protection of nature regardless of the direct benefit to humans. This view supports the idea that ecological considerations should be at the forefront of decision-making processes, often advocating for significant changes in lifestyle and policies to preserve natural habitats and biodiversity.
Identify four characteristic features of the tropical rainforest biome. [4]
High species/habitat/niche diversity/high biodiversity/hotspots/many endemic species;
High primary productivity/high photosynthetic rate/serve as major carbon sinks/produce a lot of oxygen;
High nutrient turnover/high decomposition rate;
High rates of insolation;
High mean temperatures;
Abundant precipitation/high humidity;
Nutrient-poor/acidic soils;
Thin topsoil layer/rich in organic matter/very deep overall/red colored (rich in iron);
Dominated by tall straight trees;
Complex/highly branched food webs;
Stratified ecosystem/tree buttresses in ground level, dense broad-leaved canopy, emergent trees;
Found around the Equator/between Tropics of Cancer & Capricorn;
Low/no seasonality/annual fluctuation in climate (precipitation and temperature);
Outline how the flow of energy along a food chain demonstrates the second law of thermodynamics. [4]
with each transformation along a food chain some available energy is lost;
energy is lost as heat through respiration;
commonly 90% lost with each transfer / 10% retained at each trophic level;
biomass has low entropy;
energy is transformed as it passes along the food chain;
heat increases the entropy of the environment;
so with each transformation there is an increase in entropy (as stated by second law);
Runoff from agricultural land can result in excess nutrients entering water bodies. State one management strategy that could control the release of agricultural runoff. 1
What are some soil conservation techniqes?
wind breaks, shelters, belts, conditioners, no plow areas, terracing, contour plowing
Identify four significant individuals or events and their impacts on the development of the environmental movement.[4]
Greta Thunberg raising international awareness of climate change;
Rachel Carson’s Silent Spring raising awareness of damage from pesticides;
James Lovelock’s Gaia hypothesis promoting holistic perspective of environment;
Fukushima nuclear disaster raising awareness of environmental impact of nuclear accidents;
Al Gore’s documentary “Inconvenient Truth” raising awareness of global environmental issues;
UN Climate Change Conferences promoting international agreements to address climate change;
production of plant-based ‘meats’ to promote a vegetarian diet;
development of Carbon Capture and Sequestration technology to address climate change;
What are some trends to describe data and their definitions?
TYPES OF EQUILIBRIA
o Steady-state: have continuous inputs and outputs of energy and matter, but the system remains in a largely constant state. It is a characteristic of open systems.
o Static: there is no change over time. When disrupted, if ever, it will adopt a new equilibrium.
o Stable: the system returns to the same equilibrium after a disturbance.
o Unstable: the system attains a new equilibrium after a disturbance. Unlike static equilibria, disruptions are more likely in unstable equilibria.
What is biomass and outline a method by which biomass can be measured.
Gross Productivity (GP): Total gain in biomass by an organism or trophic level over time.
Net Productivity (NP): Biomass remaining after accounting for energy lost through respiration (R); represents the energy available for growth, reproduction, and consumption by the next trophic level
Differences Between Producers and Consumers
Importance of NP in Ecosystems
Applications of GP and NP Values
Explain human impacts on flows and stores in aquatic ecosystems
Deforestation: ↓ evapotranspiration, ↓ infiltration,
↑ surface runoff → increased flooding, reduced
atmospheric moisture
Urbanization: impermeable surfaces → ↑ flash
flooding, ↓ groundwater recharge
Agriculture:
Withdrawals: irrigation, livestock deplete
surface/groundwater
Discharges: fertilizers, sewage pollute waterways
(eutrophication)
Soil compaction: ↓ infiltration, ↑ erosion → river
sedimentation
Infrastructure: dams, river diversion, canalization
alter flow regimes and local hydrology
Describe two ways in which human activities can degrade soil quality.
Explain the importance of scale in environmental systems and models. 3
What is a tipping point and what is it's impact on ecosystems/tipping points?
A tipping point is a threshold that is reached when an ecosystem experiences a shift to a new state, driving it into a new state.
Its characteristics are:
o Involve positive feedback, which makes the change self-perpetuating and drives the system further from equilibrium.
o Beyond the tipping point, a fast change of state occurs.
o The tipping point cannot be precisely predicted.
o The changes are long-lasting and difficult to reverse. o There is a large time lag between the pressures driving the change and the evidence of the impacts, making management of the change difficult.
Create the flow of energy through a trophic level that is at least 4 levels large.
Phytoplankton, Seaweed----
Zooplankton, Mussel, Limpet----
Small Fish, Jellyfish, Crustaceans, Sea Stars----
Larger Fish----
Squid---
Shark, Orca, Albatross
Explain the Thermocline layer
The conveyor belt begins near Greenland and Iceland. Dry, cold winds from northern Canada chill the ocean surface.
§ The chilling surface waters, evaporation and formation of sea-ice produces cold, salty, deep water in the North Atlantic.
§ This deep water sinks and flows along North and South America towards Antarctica, where it flows east around Antarctica.
§ The deep water mixes with Antarctic water. The resulting mix flows north into the Indian, Pacific and Atlantic Oceans.
§ The deep water gradually warms and mixes with surface waters as they flow into the northern hemisphere, continuing the conveyor belt.
Ocean currents are driven by three main forces:
Wind: Prevailing winds push surface waters, creating currents.
Earth’s Rotation: The Coriolis effect causes currents to deflect clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
Temperature and Salinity Differences: Variations in water density drive deep ocean currents.
With reference to four different properties of a soil, outline how each can contribute to high primary productivity. [4]
particle size affects ability of soil to store/retain water necessary for productivity;
high mineral content provides nutrients for healthy growth/productivity;
high organic content / deep humus provides long term storage of nutrients (released through decomposition);
air spaces provide more O2 to roots for growth/respiration / allow deeper penetration of roots;
appropriate porosity allows soil to hold enough water for plant growth;
better drainage prevents water-logging that inhibits growth/productivity;
abundant biota help to aerate/break up the soil allowing for better root growth/recycle nutrients;
microorganisms contribute to mineral-cycling promoting growth/productivity;
neutral to slightly acidic pH is the optimal for most plants (6.0–7.5);
low or no slope prevents water erosion / loss of soil;
Pollutants-what are some of the terms and their impacts?
TYPES OF POLLUTANTS
o Primary pollutants – active on emission (e.g. carbon monoxide)
o Secondary pollutants – formed when primary pollutants undergo physical or chemical changes (e.g. sulphur trioxide + water à sulphuric acid)
• TYPES OF POLLUTION
o Point-source pollution – release of a pollutant from a single, clearly identifiable source. § Easy to determine exactly who or what is causing the pollution § Easier to manage as the source is easily identified § E.g. waste disposal pipe of a sewage works into a river
o Non-point source pollution – release of pollutants from various widely dispersed sources. § May have many different sources and may be impossible to detect where exactly it is coming from. § E.g. air pollution blown many kilometres away by wind cannot be traced back to its original source.
• Persistent organic pollutants (POPs) are resistant to breaking down and remain active in the environment for a long time.
o They can bioaccumulate in animal and human tissues and biomagnify in food chains.
o Properties: § High molecular weight § Not soluble in water § Highly soluble in lipids – can pass through cell membranes
o They cause cancers and disrupt hormone functions • Biodegradable pollutants do not persist in the environment and break down quickly.
o They are broken down by decomposers or physical processes like light and heat.
o E.g. degradable plastic bags made of starch
• TYPES OF POLLUTION
o Acute pollution – large amounts of a pollutant are released at once, causing significant harm. (e.g. Bhopal Disaster in India)
o Chronic pollution – long-term release of a pollutant in small amounts. (e.g. Beijing air pollution) § May go undetected for a long time § Difficult to manage § Spreads widely.
Explain how an ecological footprint can determine sustainability.
• An ecological footprint (EF) is the area of land and water required to sustainably provide all resources at the rate at which they are being consumed by a given population.
• If EF is greater than the area available to the population, it indicates unsustainability.
• EF is increased by:
o Reliance on fossil fuels
o Increased use of technology and energy
o High amounts of imported resources
o High per capita production of carbon waste/emissions o High per capita consumption of food o Meat-rich diets
• EF is reduced by:
o Reducing use of resource
o Recycling resources
o Using renewable energy sources o Reducing reliance on fossil fuels
o Increasing efficiency of resource use
o Investing in new and efficient technologies
o Using biological controls for weeds and pests instead of synthetic pesticide
o Using high-yielding varieties of seeds
o Less dependence on meat in diet
o Less dependence on chemical fertiliser
Explain how a community of decomposers contributes to the stability of the whole ecosystem. 7
Decomposers will feed on dead organic matter/detritus (like dead leaves, wood, carcasses, faeces)...;
... reducing their accumulation/cleaning up Earth;
They will break down organic matter into inorganic matter...;
...enhancing soil fertility/increasing nutrient availability;
The inorganic minerals (nitrates, phosphates, metals) will then feed plant communities/will be absorbed by plant roots...;
...supporting high vegetation/plant abundance;
...and may support high habitat/niche diversity;
Decomposers are responsible for nutrient cycling/e.g. nitrogen cycling (nitrogen fixation/ammonification /nitrification/denitrification/phosphorus cycling/carbon cycle;
...high flow of matter may support complex food webs;
Decomposers are the basis of a detritus-based food web/important part of ecosystem flow of energy/may be eaten/pass biomass on to carnivore community...;
...supporting/stabilizing carnivore abundance;
As decomposer numbers decrease due to predation, so do carnivores;
... thereby contribute to regulation of the carnivore community/which is an example of negative feedback (leading to stability);
Decomposer will release organic matter through their own death/defecation...;
... which would provide food for other decomposers;
Decomposers participate in humus formation...;
...increasing water holding capacity of soil (and soil fertility = MPd);
Decomposers may compete with one another regulating their populations (another example of negative feedback = MPm);
Decomposers, like earthworms, loosen soil/disperse nutrients/create space for air and water circulation...;
...helping root growth/improving soil structure;
Fragmentation: larger invertebrates initially fragment larger chunks of organic matter (then bacteria and fungi complete decomposition into nutrients = MPc);
After a disturbance, decomposers will increase their metabolic/respiration rate/feeding on detritus...;
..contributing to a faster return to original state (resilience entailing stability);
Suggest ways in which a coastal indigenous food production system might differ from a
large-scale commercial food production system. 3
technology likely to be simpler;
methods likely to be more traditional;
environmental impact will probably be smaller;
more likely to be sustainable in the long term;
Compare the characteristics of soils rich in sand with soils rich in clay. [4]
Sand-Rich Soil characteristics:
Chemical Properties:
Agricultural Management:
Evaluate how different environmental value systems may attempt to manage terrestrial food production. [9]
understanding concepts & terminology of land use change; anthropocentrism; environmental pollution standards; food miles; food labelling; maximum sustainable yield; ecocentrism; local, small-scale subsistence food production; technocentrism; economic growth and commercialisation; genetic engineering; intensive farming; deforestation; overgrazing; over-tillage; vertical agriculture etc.
breadth in addressing and linking different value systems and different approaches to terrestrial food production and their implications for sustainable food production.
examples of value systems; food production strategies; aspects of sustainable food production (environmental/economic/social) etc.
balanced analysis evaluating extent to which different value systems would be effective or not in managing sustainable terrestrial food production.
a conclusion that is consistent with, and supported by analysis and examples given e.g. Technocentric approaches may appear to be the least concerned with sustainability but, actually, with appropriate anthropocentric controls, they have many strategies in which far greater efficiency can be achieved which goes a long way to achieving sustainability.
With reference to both carbon and nitrogen cycles, distinguish between stores, sinks and sources. [7]
stores of matter remain in steady state/equilibrium with the environment;
sinks involve a net accumulation of the element;
sources involve a net release of the element into the surrounding environment;
major stores of carbon cycle include the atmosphere, soils and fossil fuels;
major sinks of carbon are plants that absorb CO2 in photosynthesis;
major sources of carbon are living organisms through respiration/combustion of fossil fuels;
major store of nitrogen is in the atmosphere;
major sinks for nitrogen are plants absorbing nitrates/Haber process;
major sources of nitrogen are decomposers/denitrifying bacteria;
Synthesize how changes in environmental conditions could affect maximum sustainable yield calculations and fisheries management strategies.
Changes in environmental conditions, such as climate change, pollution, or habitat destruction, can significantly affect maximum sustainable yield calculations by altering fish population dynamics, reproduction rates, and migratory patterns.
For instance, rising ocean temperatures may reduce spawning success for certain species. Therefore, fisheries management strategies must adapt to these changes by regularly updating MSY estimates and adjusting quotas accordingly. This adaptability is crucial for maintaining sustainable practices and ensuring that both fish populations and fishing industries remain viable in the long run.
Evaluate the use of reservoirs and drought-resistant crops as a means of sustainably managing water supply. 7
Reservoirs (4 max): Pros: (3 max)
Dampens seasonal oscillations of available rainfall;
Provides a diversity of habitat;
Can be utilised for leisure activity/water sports;
Low maintenance;
Cons:(3 max)
High set-up costs;
Water may still need treatment for human consumption;
Breeding ground for disease vectors (e.g. mosquitoes);
Can lose a lot of water through evaporation;
Construction may destroy habitats/require relocation of settlement
Drought-resistant crops (4 max):Pros: (3 max)
Reduces agricultural demand for water supply;
Enables higher crop productivity;
Allows agriculture in previously unproductive lands;
Cons: (3 max)
Relatively expensive crops;
Low genetic diversity (if GMOs);
Limited range of such crops available;
Discuss, with reference to named examples, the differences between zonation and succession. [7]
Zonation e.g. mountainside/rocky shore/lake margin etc.;
There is an environmental gradient of abiotic factors;
Species will colonise the area wherever abiotic factors are favourable;
Because different species have different niche requirements, they will colonise different points along gradient;
…so the pattern of biotic components will change over distance/spatial distribution;
Succession e.g. after a fire/lithosere/psammosere (sand)/hydrosere;
Pioneers species colonise virgin habitat;
They change the physical/abiotic conditions of habitat;
…such that other species can colonise (that couldn’t before);
The community displace the previous species through competition;
The process continues toward a climax community;
…thus the community changes over time;