Midterm 1 Flashcards
Negative Feedback
A feedback resulting in stability by decreasing disturbance. ex. increase in herbivores–> increase in carnivores –> decrease in herbivores
Positive Feedback
Amplification of an effect by it’s own influence resulting in exponential growth. ex. Unregulated deer population –> increases until the vegetation cannot maintain it.
The three components of the human-environment interaction model
- Population (Size, distribution, density, growth rate)
- Resources (Natural: supply, character; and human: demand, extraction, use).
- Environmental change (biotic and abiotic)
The 5 factors influencing the interactions between population, resources and environment.
- Per capita consumption
- Public Policy
- Technology
- Culture/ Religion
- Externalities (i.e. the cost of production not included in the market price)
Definition: Externalities
the environmental cost of producing or using an economic good or service which is not included in the market price of the good or service. Ex. the greenhouse gases produced by labourers driving to work every morning to work in a factory
Definition: Common Property Resources
Resources which are free and accessible to all (ex. atmosphere, oxygen, water from the great lakes).
These resources are most commonly impacted by externalities.
Anthropocentric definition of a resource
The definition of a resource is defined based on the needs and demands of humans. i.e. a value judgement, culturally defined.
What we see as a resource is based on S.T.E.P
S.T.E.P Stands for….
Scientific knowledge, Technological knowledge, Economical knowledge and Political knowledge.
STEP is used in making value judgements of what a resource is.
Biocentric definition of a resource
Assumes the rights of non-human resources supersede human wants or needs. ex. an old growth forest has more value as an ecosystem than it has for logging.
Technocentric viewpoint
value system that is focused on technology and believe that human knowledge can surmount any problems that humans create. i.e. cornucopians
Ecocentric viewpoint
the belief that humans are part of the biosphere are so subject to it’s laws rather than our own. These people believe we should switch from managing ecosystems to the benefit of humans to controlling humans for the benefit of ecosystems.
Four characteristics of functional resources
- Resources are dynamic not static: i.e. the value of resources is changing. (ex. wood 500 years ago to now)
- Resources may be depleted (ex. fossil fuels), degraded (ex. pollution of water) and/or made obsolete (ex. extinction).
- Resources can be extended (or made to last longer) through technology and management: ex. recycling
- Resources can be hazards (ex. property on water= worth more, and more exposed to hazards such as erosion).
Definition: Flow Resource
can be depleted, sustained or increased on the basis of management. Ex. soils, forests, wildlife, fish, water, etc
Definition: Stock Resource
Physically exhaustible and may (ex. metal) or may not (ex. coal, oil, uranium, natural gas) be capable of reuse
Definition: Continuous Resource
Availability is endless and may be independent (Ex. solar energy, tidal energy) or affected by (ex. air and ocean quality) human action.
Definition: Environmental Sustainability
Maintaining or restoring the quantity or quality of biophysical resources upon which humans depend
Assessing environmental sustainability: Input Rule (two parts)
a. The harvest or consumption of renewable resources should be within the regenerative capacity of nature.
b. The depletion rates of non-renewable resources should be equal or less than the rate we develop renewable substitutes.
Assessing environmental sustainability: Output Rule
The emissions that we release into the environment must be within the assimilative capacity of the environment into which the emissions are released.
What is an environmental impact? What are the challenges with its definition?
The definition of environmental impact reflects a “value judgement” based on human demands (i.e. depends on our personal STEP).
Management is very difficult if we have no agreement on what is valuable and thus what needs to be protected.
Four types of environmental impacts: Change in…
Four types of environmental impacts are:
- Change in the quality of the biophysical environment.
- Change in biodiversity.
- Changing the supply/storage of resources.
- Changes in physical structure of the environment; ex. changing wetlands into agricultural land
Three types of problem displacement and examples of each
- Spatial Displacement: shipping waste away; building taller smoke stacks
- Displacement to another medium: i.e. incinerating waste –> reduces volume but contaminates air.
- Temporal displacement: leaving problem for future generations; ex. burying waste.
On what three items have we surpassed the boundaries of sustainability?
- Nitrogen: The release of nitrogen to the environment is much higher than can be sustained
- Climate change
- Biodiversity loss.
Lower Paleolithic/ Early Stone Age (>10,000 YBP)
- scavengers and hunters of wild animals
- opportunistic gatherers
- ate mainly meat
- highly mobile
Upper Paleolithic (~8,500-10,000 YBP)
-planted and harvested wheat and rice
sophisticated hunters and gatherers.
-mobile
-use of fire
Neolithic / Late Stone Age (~5,000-8,500 YBP)
- domesticated plants and animals
- permanent settlements
- food processing
- trade
Bronze age (<5,000 YBP)
- intensification of agriculture
- less reliance on hunting and gathering
- more and larger settlements
- metal
- sophisticated trade
Impact of fire on the environment:
Humans burned habitats to allow more areas for herbivores to graze. In New Zealanc, this was done to allow more habitat for Bracken fern.
Defintion: Pleistocene Overkill
A time period 12,000 years ago where human impact resulted in the demise of the megafauna (herbivores more than 50kg). On every continent, the megafauna went extinct promptly after the arrival of humans.
Definition: Domestication
- the controlling of the genetics of a plant or animal population by the planned selection of plant seeds and animals’ parents.
- the process by which plant and animal species come to depend on humans for survival while, in turn, providing humans with practical or other benefits
Definition: Pastoral Nomadism
This involves the rotational grazing of herbivores.
Can be completely sustainable. May not be sustainable when
- herd sizes are increased; or when
-there is natural variability of resources in a resource-limited environment and it cannot support the herd from year to year.
Definition: Shifting Cultivation
This involves crops as opposed to animals and occurs in moist environments such as rainforests. This involves clearing forest and planting crops for 2-3 years before moving on and clearing a new space. Farmers wouldn’t return to the original plot for 30-60 years, allowing the forest to regenerate.
-theoretically sustainable
Definition: Subsistence Farming
farming to provide food primarily for the farmer’s immediate family; a traditional form of farming; “farming for survival using human and animal effort”.
Definition: Industrial Farming
farming for the purpose of selling crops, animals, and related products; often specialized around selected crops or livestock (i.e. soybeans, cattle etc.). “Farming for profit, using whatever it takes”.
Industrial Revolution (1700-1900)
Coal became the main source of energy, resulting in smog days and loss of agricultural land to coal extraction.
Modern Industrial Society is characterized by four items:
- Increased production and consumption (because of advertising)
- Increased dependence on non-renewables
- shift from natural to synthetic/ technological
- increase in the amount of energy per unit output.
Two benefits of modern industrial society are:
- People are living longer due to environmental improvements
- Higher food production per capita.
Three Strategies to make modern industrial society more sustainable:
- Set environmental goals, standards and laws
- Accounting for externalities (i.e. paying the environmental cost when we buy products).
- Dealing with chemicals and hazardous waste (i.e. reducing the use of pesticides).
What are the three physical spheres?
- Atmosphere
- Hydrosphere
- Lithosphere
What three factors contributed to the creation of the earths environment?
- The earths position in the solar system (relative to the sun)
- Abundant water
- Oxygen rich
Definition: Kinetic Energy
i.e. wind
Definition: Latent Energy
involved of the change of state of water. i.e. evapotranspiration
Definition: Chemical energy
i.e. photosynthesis
Definition: Solar Energy
Energy from the sun
Definition: Geothermal Energy
Heat generated and stored in the earth
The four spheres of the atmosphere:
Thermosphere
Mesosphere
Stratosphere
Troposphere
Key components of the atmosphere (7):
Nitrogen Oxygen Argan Carbon Dioxide Water vapour Ozone Dust
Urban heat islands
One way that humans have modified atmospheric circulation.
This is where the city is at the center of a hadley cell, making it hot and dry in the city.
The key factor responsible for atmospheric circulation
Density of air and pressure systems. ex. open-top freezers
Sources of water on earth
salt water in oceans and seas
glaciers
water in lakes, soil and the atmosphere
rivers living organisms.
Hydrologic cycle
precipitation –> runoff –> evaporation –> convection –> condensation –> advection –> back to precipitation
What is responsible for the saturation of air?
Air temperature. Warm air holds more water, so when it gets cold, condensation forms. ex. air moving up a mountainside.
Definition: Orographic precipitation
precipitation caused when moist air is forced to rise when passing over a mountain range.
Definition: Convectional Precipitation
precipitation caused by the free ascent of unstable air; usually short-term, intensive rainfall that produces thunder storms.
Definition: Convergent Precipitation
takes place when air moves into a low-pressure trough or topographic depression and escapes by moving upward. i.e. at the equator. Is responsible for tropical rainforests.
Definition: Frontal Precipitation
occurs when warm air is pushed aloft as it overtakes cold air (warm front) or is overtaken by cold air (cold front). This occurs in this area.
Human impacts on the hydrosphere: Evaporation
affecting evaporation by conducting agriculture in arid regions by irrigating. ex. the Colorado river no longer runs to the ocean as its diverted for irrigation.
Human impacts on the hydrosphere: Precipitation
affecting precipitation by releasing sulfur dioxide and nitric acid into the air, resulting in acid rain.
Human impacts on the hydrosphere: Run off (and factors that influence rate of run off).
Factors that influence the rate of runoff include: amount of rainfall, vegetation, infiltration
Humans cause flooding by affecting the permeability of the soil (asphalt)
Global circulation of the lithosphere
occurs over geologic time.
Includes constructive processes (volcanoes and earthquakes) and destructive processes (weathering and erosion).
We are affecting the lithosphere by building things out of concrete, digging holes, making lakes, etc.
Definition: Weathering
the process where rocks are worn away or broken down into smaller pieces by wind ,water or plants etc
Definition: Erosion
happens when these broken rocks and sediments are picked up & moved to another place by ice, water or wind. Humans are agents of erosion and accelerate (etc.) natural agents of erosion like water, wind, glaciation, coastal waves and gravity
What are the three levels of spatial and temporal scale?
- Large/ Global
- Intermediate/ Regional
- Small/ Local
In dealing with human impact, we should match the scale of impact with the scale of solutions.; i.e. to deal with global issues, we must use global resources
Classes of contaminants in the arctic
- Persistent Organic Pollutants (POPS)
- Radionuclides
- Heavy Metals
Persistent Organic Pollutants (POPS)
a contaminant of the arctic
Industrial pesticides including PCBs, dioxin and furan
Radionuclides
a contaminant of the arctic
Caused by nuclear meltdowns, nuclear testing etc.
include strontium 90, cesium 137 plutonium
Heavy metals
a contaminant of the arctic
Come from waste incineration
includes cadmium, mercury and lead
Transportation of contaminants to the arctic:
circulation of the atmosphere (the wind blows north; the grasshopper effect) and
circulation of the hydrosphere (rivers, ocean circulations).
The Grasshopper effect
(i.e. Global distillation)
Substances are vaporized at high temps and travels to areas of lower temp and condense. This continues until the condensation reaches the arctic.
two ways that nutrients might cycle in the natural environment:
- Sedimentary Cycle
2. Gaseous Cycle
Sedimentary cycle
nutrients spend much of their time locked up in rock, but are released for use by life as a result of weathering processes. Ex. iron, copper, phosphorus
Gaseous Cycle
Nutrients spend much of their time in the atmosphere. Nutrients are exchanged between the biosphere and the atmosphere. Ex. nitrogen, carbon
Phosphorus is an example of which cycle?
A sedimentary cycle.
Phosphorus is weathered from appetite crystals. Considered a limiting resource as it is rare and weathered from rocks.
cycled rapidly in vegetation (i.e. when the plant dies its nitrogen is picked up and used/ cycled within another plant.
Nitrogen is an example of which cycle?
A gaseous cycle.
Inorganic nitrogen in the atmosphere is converted to organic nitrogen by bacteria or other processes such as heat by lightening or engines. The heat in our car engines are sufficient to send nitrogen into the atmosphere where they combine with water to make nitric acid.
Definition: denitrification
the conversion of organic nitrogen to inorganic nitrogen by bacteria.
Carbon is an example of which cycle?
A gaseous cycle
Definition: Food chain
a sequence of organisms in an ecosystem, each eating or decomposing its prey.
Definition: Food Wed
a set of interconnected food chains by which energy and matter circulate through an ecosystem. Food webs are very complicated. The web of life is the most stable when they are complex.
Definition: Energy Pyramid
the idea that there must be more organisms in the lower trophic levels in order to support the higher trophic levels. i.e. more mice than hawks; more deer than wolves.
Definition: Biome
A major regional complex of similar communities recognized by plant type and vegetation structure. (See slides for map of biomes).
Five ways that humans can impact a ecosystem
- Reduction
- Fragmentation
- Substitution
- Extinction
- Contamination
Definition: Reduction
the loss of an area or coverage of an ecosystem as a result of human impacts such as burning, agricultural development, urbanization, lumbering and etc.
Definition: Fragmentation
results of ecosystems broken down from large continuous areas into smaller parcels. Ex. when roads are built through forests.
Definition: Substitution
the replacement of one species of organism in an ecosystem with another ex. places where we find Norway Maple instead of Sugar Maple, Scots pine instead of white pine, or non-invasive replacements, such as maple trees replacing elms that were killed by disease.
Definition: Simplification
Extreme form of substitution.
reduction of the biodiversity of an ecosystem. ex. complex muscles living in an ecosystem replaced by zebra muscles; a forest replaced by a field of corn.
Definition: Extinction
The permanent loss of a species. Ex. passenger pigeons went extinct in the early 1900s. We are currently in the 6th great extinction and this one is human caused.
Definition: Contamination
Incorporation of pollutants into the ecosystem. Ex. contaminants in the great lakes.
Definition: Bioaccumulation
Type of contamination
the build-up of contaminants over time in an organism. Ex. wildlife in the arctic.
Definition: Biomagnification
Type of contamination
occurs when contaminates are passed up the food chain and concentrated along the route Example: dead beluga whales within the St. Lawrence watershed have been declared hazardous waste because of the concentrations of toxins/chemicals found within them
Definition: Synergism
Type of contamination
occurs when two chemicals act together to produce greater impacts than each individually. This frequently occurs in landfills.
The principle of limiting factors
The principle that the factor (such as a particular nutrient, water, or sunlight) that is in shortest supply will limit the growth and development of an organism or a community.
Can we feed 9 billion people? Agricultural viewpoint:
Yes, we will be able to feed 9 billion people because we have been able to keep up with the population so far with no issue.
Can we feed 9 billion people? Environmental viewpoint.
Consider soil, water, genetic diversity, etc. These people say we may be able to feed this many people, but it’s going to cause some real problems.
Six Characteristics of Modern/ Industrial Agriculture
- High technology in terms of equipment, fertilizers, irrigation, seeds and etc.
- Very expensive.
- High productivity
- Energy and fossil fuels are required
- Trade
- Economic controls and incentives.
Factors necessary to agriculture (4):
- land
- labour
- capital
- fossil fuels/ energy
Factors necessary to pastoral nomadism and shifting cultivation:
- land
2. labour and capital (in term of trading)
Factors necessary to modern industrial agriculture
- capital (money) and fossil fuels are most important
- land
- labour
Definition: The Green Revolution
the use of high yield (or high response varieties) and inputs of fertilizer, pesticides, irrigation to increase crop production. These came about when scientists developed special crops that could produce higher yields. Ex. high yield rice in Asia.
Extensification of agriculture
bringing more land into production
Intensification of agriculture
better productivity per unit of land.
Shortcomings of the green revolution
1) Health problems associated with herbicides, insecticides and pesticides
2) Social inequities: the green revolution only happened for rich people.
3) Environmental issues
What are some of the soil and water issues linking agriculture
with the environment?
- Soil erosion
- Loss of soil fertility (resulting in the use of fertilizers)
- Desertification
- Irrigation
- Salinization (i.e the build up of salt in soil)
- groundwater withdrawal
Definition: Environmentally sustainable agriculture
An agricultural system which produces food and fiber within the regenerative capacity of the resources (soil, water, biodiversity) used in the production process.
Types of environmentally sustainable agriculture
- Sustainable agriculture: does not deplete soil, pollute water, or decrease genetic diversity
- Low-input agriculture (i.e.smaller amounts of pesticide, fertilizers, growth hormones, water, and fossil fuel energy than industrial agriculture)
- Organic agriculture (relies on biological approaches)
Guidelines for sustainable agriculture
1) Restore and maintain soil fertility
2) Replace chemical inputs with biological resources where possible
3) Increase the efficiency of resource use
4) Decrease area of monoculture where possible
5) Employ IPM (Integrated Pest Management)
Integrated Pest Management (IPM): what 7 techniques does it use?
uses multiple techniques to suppress pests including:
- Biocontrol
- Chemicals, when necessary
- Population monitoring
- Habitat alteration
- Crop rotation and transgenic crops
- Alternative tillage methods
- Mechanical pest removal
Three challenges for modern agriculture
1) food production must be greater than or equal to the population increase
2) increase the productivity with out increasing our use of resources. I.e. make more food without using more water
3) All systems affected by agriculture must stay sustainable (this includes ecosystems around agricultural land).
