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University of Guelph
GEOG 1220
Lorne Bennett

Unit #1 Chapter 1 Environment Our environment consists of biotic components (living things) & abiotic components (non-living things) The definition of environment must include its legal, social, economic, and scientific aspects Environment Canada: to preserve and enhance the quality of Canada’s natural environment, conserve our renewable resources, and protect our water resources. Internal relations, politics, ethics, business management, economics, social equity, engineering, law enforcement all play a role in protecting the environment Interactions Between Human & The Biological World Environmental Geography: The study of the interrelationships between human and biophysical systems of a variety of temporal scales Natural Resources Are Vital to Survival Renewable Natural Resources (Renewable resources are sometimes called flow resources) • Sunlight • Wind energy • Soils • Agricultural crops Nonrenewable Natural Resources (Nonrenewable resources are sometimes called stock resources) • Crude Oil • Natural Gas • Coal • Copper, Aluminum and other Metals Resource Management: Decision making and planning aimed at balancing the use of a resource with its protection and preservation (Balance the rate of withdrawal from the stock with the rate of renewal or regeneration) Resource Consumption Exerts Social & Environmental Impacts I = Impact on the Environment P = People A=Affluence (abundance of goods) T = Technology I = Px Ax T Carrying Capacity: is a measure of the ability of a system to support life. The number of individuals that can be sustained by the biological productivity of a given area of land Tragedy of the Commons: Each individual withdrawals whatever benefits available from the common property as quickly as possible until the resource becomes depleted. Ecological Footprint: (inverse of carrying capacity) Expresses the environmental impact of an individual or population. Is calculated in terms of the area of land and water required to provide the raw materials to the population and to absorb or recycle the wastes produced. Bio-capacity: The capacity of a terrestrial or aquatic system to be biologically productive and to absorb waste, especially carbon dioxide (we use 39% more resources than are sustainable) The Nature of Environmental Geography Geography is an Interdisciplinary Field: employs concepts and techniques from numerous disciplines and brings research results from the disciplines together Environmentalism: Asocial movement dedicated to protecting the natural world, and by extension humans from undesirable changes brought about by human choices Science: Asystematic process for learning about the world and testing our understanding of it Scientific Method (Figure 1.6 on pg. 15):Atechnique for resting ideas with observations, it involves several assumptions and a series of interrelated steps. It relies on the following assumptions: • The universe functions in accordance with fixed natural laws that do not change from time to time or from place to place • All events arise from some cause and, in turn, lead to other events • We can use our senses and reasoning abilities to detect and describe natural laws that underlie the cause-and-effect relationships we observe in nature Scientific Method Steps: 1. Make observations 2. Ask Questions 3. Develop a hypothesis (an educated guess that explains a phenomenon or answers a scientific question) 4. Make predictions (scientific statements that can be directly and clearly tested 5. Test the predictions 6. Analyze and interpret results Independent Variable: The variable the scientist manipulated Dependent Variable: The variable that depends on the independent Controlled Experiment: Scientists control for all variables except for the one being tested Casual Relationships: changes in the independent cause changes in the dependent Manipulative Experiment: When a researcher actively chooses and manipulates the independent variable Natural Experiments: are observational studies and are not controlled in the traditional sense The scientific process does not end with the scientific method • Peer Review • Conference Presentations • Grants and Funding • Repeatability • Theories Sustainability & The Future of Our World Scientists have firmly concluded that human activity is altering the composition of the atmosphere and that these changes are affecting the earth’s climate Today’s Biodiversity: The Cumulative number and diversity of living things is declining dramatically Millennium EcosystemAssessment • Over the past 50 years, humans have changed ecosystems dramatically to do high levels of consumption. This has resulted in a irreversible loss of the diversity of life on earth • Changes to ecosystems have caused an increase in human well being at the cost of the degradation of ecosystems and the services they provide for us. And the exacerbation of poverty for some people • This degradation could grow significantly worse during the first half of this century • The challenge of reversing degradation of ecosystems while meeting increasing demands for their services can be partially overcome, but doing so will involve significantly changing many policies, institutions and practices Sustainable Development: The use of renewable and nonrenewable resources in a manner that satisfies our current needs without compromising their future availability Chapter 2, pg. 33-40 Earth’s Environmental Systems Systems: Anetwork of relationships among parts, elements, or components that interact with and influence one another through the exchange of energy, matter or information Open Systems: receive inputs of both energy and matter and produce outputs of both Closed Systems: receive inputs and produce outputs of energy, but not matter. Matter exists within the system but does not enter or leave Feedback loop: When a systems output can serve as input to that same system Negative Feedback Loop: output that results from a system moving in one direction acts as input that moves the system in the other direction, therefore stabilizing the system (i.e. thermostat regulating heat in a house) Positive Feedback Loop: Rather then stabilizing the system they drive it further toward one extreme or another (i.e. erosion) When processes within the system move in opposing directions at equivalent rates so that their effects balance out the process is said to be in a state of dynamic equilibrium Dynamic: even though the system is in balance, it is an ever-changing, ever-adjusting balance, not static or unchanging Homeostasis: the tendency of a system to maintain constant or stable internal conditions. • Resistance: refers to the strength of the system’s tendency to remain constant; that is to resist disturbance • Resilience: Ameasure of how readily the system will return to its original state once it has been disturbed • Homeostatic systems are said to be in a stable or steady state Emergent properties: characteristics not evident in the components alone Complex systems often have multiple sub systems: determining where one system ends and another begins can often be difficult (i.e. computer, tree, St. Lawrence River) Environmental Systems May be perceived in Various Ways Geosphere: The rock and sediment beneath our feet, in the planets uppermost layers Atmosphere: Is composed of the air surrounding our planet Hydrosphere: All water on the surface & underground Cryosphere: The subsystem that consists of the permanently frozen parts of the hydrosphere Biosphere:All planets living organisms Anthroposphere: (also known as anthrosphere or technosphere) encompasses the parts of the environment that are built or modified by human use, including the built environment we live and work in (scientists are arguing this new system) Ecosystems Ecosystem: consists of all organisms living and nonliving entities that occur and interact in a particular area at the same time Ecosystem Ecology: The study of energy and nutrient flows among living and nonliving components of systems Energy is converted to Biomass Biomass: Organic materials of which living organisms are formed. (Is the result of photosynthesis to capture the suns energy to produce food) Gross Primary Production (GPP): the conversion of solar energy to the energy of chemical bonds in sugars by autotrophs. Autotrophs use a portion of this production to power their own metabolism by respiration. Net Primary Production (NPP): The energy that remains after respiration, and that is used to generate biomass Therefore, NPP = GPP – respiration by autotrophs Heterotrophs: eat plants and use the energy gain from plants for their own metabolism, growth, and reproduction Secondary Production: Total biomass that Heterotrophs generate by consuming autotrophs Productivity: The rate at which plants convert energy to biomass Nutrients: Elements and compounds that organisms consume and require for survival • Micronutrients: elements and compounds required in relatively small amounts • Macronutrients: elements and compounds required in relatively large amounts (nitrogen, carbon) Chapter 7, pg. 186-190 There are Several Major Causes of Biodiversity 4 primary causes of population decline and species extinction 1. Habitat alteration a. Primary source of population declines 83% of threatened mammals & 85% of threatened birds b. Habitat being lost most rapidly is the rain forests, dry forests and savannas c. Artic sea ice habitat required by polar bears is disappearing faster then ever 2. Invasive species a. Non-native species in new environments 3. Pollution 4. Overharvesting a. High levels of hunting (polar bear, many whales) Climate change is becoming the 5 primary cause of population decline and species extinction a. Extreme weather events such as drought b. Not all species will be able to adapt c. A1.5-2.5 degrees global temperature increase could put 20-30% of the world’s plants and animals at risk Unit #2 The Hunter-Gatherers • Humans have spent 99% of their time on Earth as hunter-gatherers o Only in the last 10 000 years has there been any change o This is when we began to domesticate plants and animals, use stone and metals effectively, and create and use energy outside of our own muscles Lower Paleolithic • 20 000 years ago, we discovered that fish could be eaten and were nutritious • 14 000 years ago we find evidence of fish traps constructed in Europe disgned to trap salmon • 10 000 years ago, there were roughly 5 million people o put little stress on the world’s natural resources Upper Paleolithic • Farming became widespread • Some villages appeared Neolithic or Late StoneAge • Tools became more sophisticated but were still made of stone, bone and wood • Hunting and gathering became a science • Domesticated animals replaced wild ones for food • Villages increased in siz • People began taking the first steps in understanding how to utilize and control energy BronzeAge • Appearance of hand-crafted metal tools • Evidence of surplus food • Notable population increase Environmental Impacts of Hunter-Gatherers Impact of Fire • Used to drive game into an ambush or over cliffs • Used to burn vegetation and produce grasslands for grazing Impact of Hunting • Between 12000 and 10000 B.P., about 200 genera of animals became extinct in NorthAmerica o Referred to as the Pleistocene Overkill Impact of Gathering • Sustainability of certain species was tested as a result of over-harvesting TheAgricultural Revolution: Transition 1 • 4 lines of evidence archaeologists use to suggest the existence of agriculture at a location: o Finding species outside their normal range o Species in suddenly higher numbers than normal o Unnatural sex ratio o Unexplainable change in appearance to the species • The first animal believed to be domesticated was the dog (12000-22000 years ago) SustainableAgriculture • Pastoral Nomadism: the rotational grazing of domesticated herbivores • Nomadists allow grazing in an area for a limited time and then move to another grazing site, allowing natural processes to restore grasses at the original site • Environmental Impacts – theoretically, it is a stable production system, but sometimes the pasture resources are degraded due to: o Cultural value – in some locations, wealth is measured by the number of cattle, leading to overgrazing o Natural variability of resources in a resource-limited environment – carrying capacity varies per year because of variations in rainfall o Too many people, too small an area Shifting Cultivation (Slash & Burn or swidden agriculture) • Ashift in the location of cultivated fields over time • Environmental impacts – this is also considered a stable production system, but cultivated environments are sometimes severely degraded because: o Clearing – reduced habitat o Burning – heat burns organic matter, creating reduced soil fertility The Industrial Revolution: Transition 2 • The stages of industrialization are characterized by: o Increasing extraction, processing and use of a variety of resources o Changing technologies designed to produce more goods and services more efficiently • Bronze & IronAges o Archaeological evidence suggests that many environmental impacts occurred at this time:  There was increased deforestation  Cultivation of landscape resulted in notable shift in nutrient rich soils from hilltops to valley bottom  Human settlements and settlement patterns shifted from hills to vallies • Clear Human Impacts from Industrial Revolution o There was considerable migration of people from the countryside to towns and cities o Modern tools made the demand for labour decrease, but increased agricultural output o Development of larger towns and cities introducted the problems associated with waste, sewage and domestic garbage o The “coal landscape” evolved: mining facilities, coal heaps, dust, etc. o Towns and cities air/water quality was degraded due to industries • Benefits from Industrial Revolution o Numerous useful goods o Increased food production per capita o Increased average life expectancy o Decline in population growth o Increased knowledge • Governments recently took action too: o Set environmental goals o Set target emissions standards for various industries o Create environmental laws Unit #3 Chapter 2, pg. 46-47 The Hydrological Cycle influences all other cycles • Water is the essential medium for all manner of biochemical reactions • Water carries nutrients and sediments from the continents to the oceans via rivers, streams, and surface runoff • The water cycle (hydrological cycle) summarizes how water (liquid, gas and solid forms) flows through the environment • Water moves from oceans, lakes, ponds, rivers, and moist soil into the atmosphere by evaporation (the conversion of a liquid to gas form) o Warm temperatures and strong winds speed rates of evaporation • Water also enters the atmosphere by transpiration (the release of water vapour by plants through their leaves) • Transpiration and evaporation act as natural process of distillation, effectively creating pure water by filtering out minerals carried in solution • Water returns from the atmosphere to Earth’s surface as precipitation when water vapour condenses and falls as rain or snow • Precipitation may be taken up by plants and used by animals, but much of it flows as runoff into streams, rivers, lakes, ponds, and oceans • Some precipitation and surface water soaks down through soil and rock to recharge underground reservoirs called aquifers • Aquifers are porous bodies of rock and soil that hold groundwater (water found underground beneath all layers of soil); they can hold groundwater for long periods of time Our Impacts of the Hydrologic Cycle are Extensive • Human activity affects every aspect of the water cycle o By damming rivers to create reservoirs, we increase evaporation and, in some cases, infiltration or surface water into aquifers o By altering Earth’s surface and its vegetation, we increase surface runoff and erosion o By spreading water on agricultural fields, we can deplete rivers, lakes, and streams, and increase evaporation o By removing forests and other vegetation, we reduce transpiration and may lower water tables o By emitting into the atmosphere pollutants that dissolver water droplets, we change the chemical nature of precipitation, in effect sabotaging the natural distillation process that evaporation and transpiration provide • Most threatening to our future, we are overdrawing groundwater to the surface for drinking, irrigation, and industrial use and have thereby begun to deplete groundwater resources o Water shortages have already given rise to numerous conflicts world wide Chapter 5, pg. 107-110 Soil is a Complex, Dynamic Mixture • Soil: a complex plant-supporting system that consists of disintegrated rock, organic matter, water, gases, nutrients and microorganism o Fundamental to the support of life on the planet and the provision of food for the growing human population o Renewable  only if managed carefully • Soil consists very roughly of half solids, mostly mineral matter with varying proportions of organic matter, and the rest is pore space taken up by air, water, and other soil gases • The mineral particles in soil are inherited from the parent material (the base geological material in a given location, from which the soil is formed)  the parent material determines the starting composition of the soil • The organic matter in soil includes living and dead microorganisms as well as decaying material derived from plants and animals • Soil provides habitat for earthworms, insects, mites, millipedes, centipedes, nematodes, sow bugs, and other invertebrates, as well as burrowing mammals, amphibians, and reptiles • Soil can have as much influence on a region’s ecosystem as do the climate, latitude, and eleveation • Soil itself meets the definition of an ecosystem Soil Formation is Slow & Complex • The formation of soil begins when the parent material (i.e. lava, volcanic ash, etc…) is exposed to the effects of the atmosphere, hydrosphere, & biosphere • Weathering: describes the physical, chemical, and biological processes that break down rocks and minerals, turning large particles into smaller particles, which are the precursors of soils • Physical (mechanical) weathering: breaks rocks down without triggering chemical change in the parent material; temperature, wind, rain, and ice are the main agents • Chemical Weathering: results when water or other substances chemically interact with parent material (i.e. limestone looks worn and smooth) • Biological Weathering: occurs when living things break down parent material by physical or chemical means • Biological activity further contributes to soil formation through the deposition, decomposition, and accumulation of organic matter • Partial decomposition of organic matter creates humus (a dark, spongy, crumbly mass of material made up of complex organic compounds) • Peat: soils that are dominated by partially decayed, compressed, organic material • Weathering produces fine particles and is the first step in soil formation • Erosion: the movement of particles from one location to another; particularly prevalent when soil is stripped of vegetation, leaving the surface exposed to water and wind that may wash or blow it away • Sediment: when soil or regolith is transported by wind, water, or ice and then deposited elsewhere • Weathering, erosion, the accumulation and transformation of organic matter, and the other processes that contribute to soil formation are all influenced by environmental factors • Formation of soil influenced by 5 primary factors (climate, organisms, topography, parent material, & time) Chapter 9, pg. 243-259 Freshwater Systems • Water that we drink is actually quite rate and limited (Figure 9.1 on pg. 245) • Fresh water: water that is relatively pure, with few dissolved salts • Just over 1 part in 10,000 of Earth’s water is easily accessible for human use • As water moves, it redistributes heat, erodes mountain ranges, builds river deltas, maintains organisms and ecosystems, shapes civilizations, and gives rise to political conflicts Rivers & Streams Wind Through Landscapes • Tributary: a small river flowing into a large one • Drainage basin/watershed: the area of land drained by a river and all it tributaries • Floodplain: areas nearest a river’s course that are flooded periodically are said to be within the river’s floodplain; frequent disposition of silt from flooding makes floodplain soils especially fertile o As a result, riparian (riverside) are productive and species rich Wetlands include Marshes, Swamps, & Bogs • Systems that combine elements of fresh water and dry land are enormously rich and productive  often lumped under the term wetlands • In freshwater marshes, shallow water allows plants to grow above the water’s surface • Swamps: consist of shallow water, rich in vegetation, but they occur in forested areas • Bogs: ponds thoroughly covered with thick floating mats of vegetation and can represent a stage in aquatic succession • Wetlands are extremely valuable as habitat for wildlife; they also provide important ecosystem services by slowing runoff, reducing flooding, recharging aquifers, and filtering pollutants Lakes & Pons are Ecologically Diverse Systems • Littoral Zone: the region ringing the edge of a water body • Benthic Zone: extends along the bottom of the entire water body, from shore to deepest point • Limnetic Zone: in the open portion of the lake or pond, away from shore, sunlight penetrates the shallow waters; sunlight intensity (and therefore water temperature), decreases with depth • Profundal Zone: below the limnetic zone, the volume of open water that is in the aphotic zone, that is, the depth below which sunlight does not reach o It is by definition, aphotic, whereas the benthic zone may be photic or aphotic • Oligotrophic lakes and ponds, which have low-nutrient and high-oxygen conditions, may slowly give way to the high-nutrient, low oxygen conditions of eutrophic water bodies Groundwater Plays Key Roles in the Hydrologic Cycle • Groundwater makes up 1/5 of Earth’s freshwater supply and plays a key role in meeting human water needs • Groundwater is contained with aquifers (porous formations of rock, sand, or gravel that hold water) • Water table: boundary between the two zones of an aquifer • Any area where water infiltrates Earth’s surface and reaches an aquifer below is known as an aquifer recharge zone • Confined aquifer (artesian aquifer): exists when a water-bearing porous layer of rock, sand, or gravel is trapped between upper and lower layers of less permeable substrate (often clay) • Unconfined aquifer: has no impermeable upper layer to confine it, so its water is under great pressure and can be readily recharged by surface water • Discharge zones: groundwater flows downhill and from areas of high pressure to areas of low pressure, emerging to join surface water bodies at discharge zones Water is Unequally Distributed Across Earth’s Surface • Different regions, even different areas within the same country, can possess vastly different amounts of groundwater, surface water, and precipitation • People are not distributed across the globe in accordance with water availability • Asia possesses the most water of any country but has the least available water per person Climate Change will cause Water Problems and Shortages • Environment Canada reports that climate change is expected to affect fresh water and the hydrologic cycle in Canada in 4 main ways: 1. The present midlatitude rain belt will shift northward 2. Snowmelt and spring runoff will occur earlier than at present 3. There will be more evapotranspiration, which will start earlier and continue longer 4. The interior continental region will experience drier summers How we use Water • Diversions: the re-routing of water from its natural river channel by means of built structures • Channelization: artificial channel modifications, including straightening and concrete-lining of channels • Dam: any obstruction placed in a river or stream to block the flow of water so that water can be stored in a reservoir Chapter 11, pg. 309-336 TheAtmosphere & Weather • Atmosphere: the thin layer of gases that surrounds Earth; it provides us with oxygen, absorbs hazardous solar radiation, burns up incoming meteors, transport and recycles water and nutrients, and moderates climate; consists roughly 78% nitrogen gas and 21% oxygen gas • Troposphere: the bottom layer, blankets Earth’s surface and provides us with the air we need to live; movement of air within here is largely responsible for planets weather • Stratosphere: extends from 11 km to 50 km above sea level; similar in composition to the troposphere, but is 1000 times as dry and less dense • Ozone Layer: the portion of the stratosphere that is roughly 17 km to 30 km above sea level and where most of the atmosphere’s minute amount of ozone concentrates; greatly reduces the amount of radiation that reaches the Earth’s surface; vital for life on Earth • Mesosphere: above stratosphere, extends from 50 km to 80 km above sea level; air pressure is extremely low and temperatures decrease with altitude • Thermosphere: atmosphere’s top layer, extends upwards to an altitude of 500 km Atmospheric Properties include Temperature, Pressure & Humidity • Atmospheric Pressure: the force per unit of area produced by a column of air, also decreases with altitude because at higher altitudes few molecules are pulled down by gravity (figure 11.3, pg. 312) • Relative humidity: property of air, the ratio of water vapour a given volume of air contains to the maximum amount it could contain at a given temperature; low humidity speeds evaporation and makes it feel colder Solar Energy Heats theAtmosphere, Helps Create Seasons, and Causes Air to Circulate • Energy from the sun heats the air in the atmosphere, drives air movement, helps create seasons, and influences weather and climate • About 70% of solar energy is absorbed by the atmosphere and planetary surface, while the rest is reflected back into space • Radiation is highest near the equator and weakest near the poles (figure 11.3, pg. 313) TheAtmosphere Drives Weather & Climate • Weather: specifies atmospheric conditions over short time periods, typically hours or days, and within relatively small geographic areas • Climate: describes the pattern of atmospheric conditions found across large geographic regions over long periods – seasons, years, millennia Air Masses Interact to Produce Weather • Front: the boundary between air masses that differ in temperature and moisture (and therefore density) • Warm front: the boundary along which a mass of warmer, moister air replaces a mass of colder, drier air (Figure 11.7A, pg. 315) • Cold Front: the boundary along which a colder, drier air mass displaces a warmer, moister air mas (Figure 11.7B, pg. 315) • High-pressure system: contains air that moves outward away from a center of high pressure as it descends; high-pressure systems typically bring fair weather • Low-pressure system: air moves toward the low atmospheric pressure at the center of the system and spirals upward; the air expands and cools; Clouds and precipitation often results • Thermal inversion: the departure from the normal temperature profile known as a temperature/thermal inversion (Figure 11.8B. pg. 316) • Vertical mixing normally allows air pollution to be diluted upward, but thermal inversions trap pollutants near the ground Large-scale circulation systems produce global climate patterns • Hadley cells: near the equator, solar radiation sets in motion a pair of convective cells; here, where sunlight is most intense, surface air warms, rises, and expands; as it does so, it releases moisture, producing the heavy rainfall that gives rise to tropical rainforests near the equator • Two pairs of similar but less intense collective cells, called Ferrel cells & Polar cells, lift air and create precipitation around 60 degrees latitude north and south and cause air to descend at around 30 degrees latitude in the polar regions • These 3 pairs of cells account for the latitudinal distribution of moisture across Earth’s surface: warm, wet climates near the equator; arid climates and major deserts near 30 degrees latitude; moist, temperate regions near 60 degrees latitude; and dry cold conditions near the poles • Coriolis Effect: a deflection resulting in curving global patterns; as a result the Earth’s rotation on its axis, the north-south air currents of the convective cells are deflected from a straight path at some portions of the globe move beneath them more quickly than others • Trade winds: between the equator and 30 degrees latitude, the trade winds blow from east to west OutdoorAir Pollution • Air pollution: refers to the release of air pollutants; outdoor air pollution is usually called ambient air pollution We Create Various Type of OutdoorAir Pollution • Primary Pollutants: pollutants emitted into the troposphere in a form that can be directly harmful or that can react to form harmful substances; examples include soot and carbon monoxide • Secondary Pollutants: harmful substances produced when primary pollutants interact or react with constituents of the atmosphere; include tropospheric ozone and sulfuric acid CriteriaAir Contaminants • Criteria Air Contaminants (CACs): produced in varying quantities by a number of processes, including the burning of fossil fuels • Sulfur dioxide (SO 2: a colorless gas with a strong odor; vast majority results from the combustion of coal for electricity generation and industry • Nitrogen dioxide (NO )2 a highly reactive, foul-smelling reddish brown gas that contributes to smog and acid precipitation; belongs to nitrogen oxides which result when atmospheric nitrogen and oxygen react at the high temperatures created by combustion engines; more than half result from combustion in motor vehicle engines • Particulate Matter (PM): composed of solid or liquid particles small enough to be suspended in the atmosphere; includes primary pollutants, such as dust and soot, as well as secondary pollutants, such as sulfates and nitrates • Volatile organic compounds (VOCs or VOX): carbon-containing chemicals used in and emitted by vehicle engines and a wide variety of solvents and industrial processes, as well as many household chemicals and consumer items • Carbon monoxide (CO): a colourless, odourless gas produced by the incomplete combustion of fuel • Ammonia (NH ): a colourless gas with a pungent odour: it is the smell associated with urine 3 • Tropospheric Ozone (O ):3also called ground-level ozone to distinguish it from the ozone in the stratosphere, which shields us from the dangers of UV radiation • Heavy metals: can be transported by the air, enter our water and food supply, and reside for long periods of sediments • Toxic air pollutants: a broad category of “other” pollutants identified by CEPAas being harmful or toxic, and therefore subject to regulation, control, and monitoring; include substances known to cause cancer, reproductive defects, or neurological, developmental, immune system, or respiratory problems in people Smog is the most common, widespread air quality problem • Smog: describes unhealthy mixtures of air pollutants that often form over urban areas • Industrial smog: grey-air smog (i.e. the dead air smog that enveloped London in 1952) Photochemical Smog is Produced by a Complex Series of Reactions • Aphotochemical process is one whose activation requires light • Photochemical Smog: also known as brown air smog, formed through the light-driven chemical reactions of primary pollutants and normal atmospheric compounds that produce a mix of more than 100 different chemicals • Airshed: the geographic area associated with a particular air mass Synthetic Chemicals Deplete Stratospheric Ozone • Chlorofluorocarbons (CFCs): mass produced by industry at a rate of 1 million metric tons per year in the early 1970s, growing at a rate of 20% per year; can deplete stratospheric ozone by releasing chlorine atoms that split ozone molecules, creating from each of them an oxygen molecule and a CIO molecule • Ozone hole: a thinned ozone concentration resulting from stratospheric ozone levels overAntarctica declining at a rate of 40%- 60% in the previous decade The Montreal ProtocolAddressed Ozone Depletion • Montreal Protocol: signatory nations agreed to cut CFC production in half; 5 follow-up agreements strengthened the pact by deepening the cuts, advancing timetables for compliance, and addressing related ozone-depleting chemicals Acidic Deposition is another Transboundary Pollution Problem • Acidic Deposition: refers to the settling, or deposition, of acidic or acid-forming pollutants from the atmosphere onto Earth’s surface; can occur through acidic precipitation, by fog, gases, or by the deposition of dry particles • Acidic deposition is one type of atmospheric deposition, which refers more broadly to wet or dry deposition of land of a wide variety of pollutants, including mercury, lead, nitrates, organochlorides, and others • Acidic deposition originates primarily with the emission of sulfur dioxide and nitrogen oxides • Main cause is human-generated air pollution, but natural causes such as sulfur-rich volcanic eruptions play a role too • Acid precipitation mobilizes toxic metal ions, such as aluminum, zinc, mercury, and cooper, by chemically converting them from insoluble forms to soluble forms Unit #4 Chapter 2, pg. 37-40 Ecosystems Ecosystem: consists of all organisms living and nonliving entities that occur and interact in a particular area at the same time Ecosystem Ecology: The study of energy and nutrient flows among living and nonliving components of systems Energy is converted to Biomass Biomass: Organic materials of which living organisms are formed. (Is the result of photosynthesis to capture the suns energy to produce food) Gross Primary Production (GPP): the conversion of solar energy to the energy of chemical bonds in sugars by autotrophs. Autotrophs use a portion of this production to power their own metabolism by respiration. Net Primary Production (NPP): The energy that remains after respiration, and that is used to generate biomass Therefore, NPP = GPP – respiration by autotrophs Heterotrophs: eat plants and use the energy gain from plants for their own metabolism, growth, and reproduction Secondary Production: Total biomass that Heterotrophs generate by consuming autotrophs Productivity: The rate at which plants convert energy to biomass Nutrients: Elements and compounds that organisms consume and require for survival • Micronutrients: elements and compounds required in relatively small amounts • Macronutrients: elements and compounds required in relatively large amounts (nitrogen, carbon) Chapter 2, pg. 44-55 Biogeochemical Cycles Biogeochemical Cycles: the cycle of nutrients through the ecosystem and global environment. This cycle consists of biological, geological, chemical, and physical processes. Materials move through the atmosphere, hydrosphere, and geosphere Residence time: the time it takes for nutrients to move from one reservoir to another Flux: the movement between reservoirs Sources: a reservoir that releases more nutrients than it takes in Sinks: a reservoir that requires more nutrients than it releases Turnover time: time for atoms to be flushed through a reservoir; balance of input to reservoir and output The hydrologic cycle influences all other cycles Hydrologic cycle: the cycle/flow of water through the environment Evaporation: water moves into the atmosphere from a liquid form to a gas form (warmer weather increase speed rates) Transpiration: the release of water vapour by plants through their leaves (also water moving into the atmosphere) Precipitation: water returning from the atmosphere to the Earth’s surface in the form of rain or snow Runoff: water from the atmosphere landing on the Earth’s surface and flowing into streams, rivers, etc… Aquifers: underground reservoirs, which are porous rock and soil that hold groundwater Our impacts on the hydrologic cycle are extensive • River dams: increase evaporation • Altering the Earth’s surface/vegetation: runoff and erosion increase • Agriculture: deplete freshwater reservoirs • Clear cutting forests: decrease transpiration • Atmospheric pollutants: change in chemical nature of precipitation destroys natural distillation • Overdrawing groundwater for drinking/irrigation/industrial use The carbon cycle circulates a vital organic nutrient Carbon: an ingredient in carbohydrates, fats, and proteins and in the bones, cartilage, and shells of all living things Carbon cycle: the route that carbon atoms take through the environment Terrestrial/aquatic plants, algae and cyanobacteria draw carbon dioxide out of the atmosphere/surface water to use in photosynthesis. This process breaks the bonds in carbon dioxide (CO )2and water (H O2 to produce oxygen (O ) 2nd carbohydrates. Autotrophs use some of the carbohydrates to fuel their own respiration, thereby releasing some of the carbon back into the atmosphere and oceans as CO .2 Decaying matter settles in ocean basins or freshwater wetlands. Layers of sediment accumulate. Older layers experience high-pressure and result in fossil fuels – coal, oil, etc… as well as sedimentary rock – limestone We are shifting carbon from the geosphere to the atmosphere Fossil fuel extraction releases carbon with a residence time of millions of years Fossil fuel combustion releases carbon dioxide and increases carbon flux from geosphere to atmosphere Vegetation clear cutting/burning releases carbon into atmosphere • Scientists are unsure where roughly 1 to 2 billion metric tonnes per year of carbon is going, and depending on where it is, it could affect climate change at an alarming rate The nitrogen cycle involves specialized bacteria th Nitrogen: makes up 78% of our atmosphere by mass, and is the 6 most abundant element on Earth • An essential ingredient in the proteins that build our bodies, and essential nutrient for plant growth Nitrogen cycle: requires assistance moving from lightning, highly specialized bacteria, or human intervention to move from atmosphere to all living organisms Nitrogen fixation: one of two ways – lightning and bacteria • Bacteria live on many plants and provide nutrients by converting nitrogen into a consumable form Nitrification: performed by specialized soil bacteria - ammonium ions converted to nitrite ions and then to another stage of nitrite ions – plants take up these ions, available after deposit on soil or water or nitrate fertilizer Denitrification: converting nitrates back into gaseous nitrogen Impact of nitrogen cycle • Rates of fixed nitrogen into terrestrial ecosystems has doubled and is increasing • Increasing rates of nitrogen that produce smog • Fertilizer flushes out essential nutrients, depleting soil quality • Acid surface water and soil • Increase of nitrogen river to ocean transfer • Marine fisheries harmed • Reduced biological diversity The Phosphorous cycle involves mainly geosphere and ocean Phosphorous cycle: key for cells and molecules. Is contained in rocks and its ions released through weathering. Phosphates dissolve into solids and settle at the bottom of water; enter the reservoir as sediment. It is a rare and limiting factor for plant growth. It passes to plants through water. It is consumed by primary and secondary consumers and released as waste by these consumers Impact of Phosphorous cycle: • Through its extraction for inorganic fertilizers • Detergents are high in phosphates Chapter 3, pg. 63-67 Limiting factors restrain population growth Limiting factors: physical, chemical and biological characteristics of the environment that restrain population growth • Ultimately determines carrying capacity • Measured with logistic growth curve that is a sharp incline at the beginning but tapers off as limiting factors increase Density-dependent factors: i.e. high population can increase mate availability but also increase competition and predation/disease Density-independent factors: factors not influenced by population (i.e. floods, fires, etc…) Reproductive strategies vary from species to species Biotic potential: maximum capacity of organisms to produce offspring in ideal conditions (i.e. fish lays thousands of eggs with short gestation) K-selected: large animals with low biotic potential devote large amounts of energy/resources to car/protect young R-selected: species focus on quantity of offspring, have high biotic potential, no parental care aftr birth Chapter 4, pg. 80-100 Energy passes among tropic levels Tropic level: feeding hierarchy. Plants capture solar energy and convert it to sugars through photosynthesis • Producers/autotrophs eat the plants • Consumers/heterotrophs receive energy from other organisms • Detritivores/decomposers consume energy from waster products or the dead bodies of other community members • Rule that each level loses 10% of the original energy Keystone species: vital for holding an ecosystem together (i.e. wolves in NorthAmerica to maintain elk, deer and moose populations) Communities respond to disturbance in different ways Resistance: resists change/remains stable Resilience: changes in response to disturbance but returns to original state Succession follows sever disturbance Succession: series of changes following a severe disturbance to a community Primary succession: biotic community is built from scratch as no vegetation or soil remain Secondary succession: elements of prior biotic community remain and it is rebuilt on that basis Pioneer species: species that arrive first and colonize the new substrate (lichens are best known for this) Climax community: remains until some disturbance restarts succession Invasive species pose new threats to community stability Invasive species: non-native species that can become dominate and alter a community Earth’s Biomes Biome: major regional complex of similar communities – large ecological unit recognized by dominate plant type vegetation Ecoregion: a large area of land or water that contains a geographically distinct assemblage of natural communities that share a large majority of their species and ecological dynamics, share similar environmental conditions, and interact ecologically in ways that are critical for their long-term persistence World can be divided into 10 terrestrial biomes: Tundra • Dry biome, almost as dry as a desert • Located along Russia, Canada and Scandinavia • Cold winters, little daylight, cool summers • No trees, vegetation • Soil has permafrost – freezes in winter- partially melts in summer, creating shallow surface water for insects & mosquitoes • Caribou can migrate to breed • Polar bears and musk oxen survive year round Boreal forest • Northern coniferous forest – also called taiga • Located across Canada,Alaska, Russia, & Scandinavia • Coniferous trees (evergreen) • Cooler, drier region – long cold winter and short, cool summer • Soil – typically nutrient poor and acidic Temperate deciduous forest • Located in central and southern great lakes, North America, Europe & China • Broad leafed trees • Trees lose leaves each fall: oaks, maples, etc… • Soil moderately fertile but less so than tropical forests Temperate grassland • Located further west – great plains/prairies • Supports grasses easier then trees • Mostly converted to agricultural land Temperate rainforest • Contains coniferous trees such as cedars, spruces, hemlocks, and douglas fir • Soil is quite fertile • Area is home to moisture living organisms • If forests are cleared, area is susceptible to landslides and erosion • Biggest threat – logging and road building Tropical rainforest • High rainfall and close to the equator • Warmer year round temperature – greater biodiversity • Poor, acidic soil and low organic matter • Nutrients contained in trees, vines and plants • Found in central America, southAmerica, southeastAsia, and west Africa Tropical dry forest • Warm temperature year round • Lower rainfall • Located in India, Africa, South America, northern Australia • Wet and dry seasons span half the year respectively • Rain season can yield heavy rainfall, leading to erosion • Mostly converted to agriculture Savannah • Tropical grassland interspersed with acacias and trees • Located in areas ofAfrica, south America,Australia, india • Precpitation falls during very distinct rainy seasons • Common animals: zebra’s, gazelles, giraffes, lions, & hyenas Desert • Rain is very sparse • Driest biome on earth • Rainfall influences vegetation • Low humidity and low vegetation • Soil has high level of salinity Mediterranean • Consists of scrub woodland • Highly seasonal • Located by California, Chile, southern Australia • Area is subject to fires Unit #5 Chapter 5 Delineate the fundamentals of soil science, including soil-forming processes • Soil is a complex system that consists of mineral fragments with varying proportions of organic matter, with the rest of the pore space taken up by soil water and gases • The diverse biotic communities in soil include living and dead microorganisms, as well as larger organisms such as earthworms and other invertebrates, burrowing mammals, amphibians and reptiles • Soil formation begins with the breakdown of parent rock by physical (mechanical), chemical, or biological weathering • Climate, organisms, relief, parent material and time are factors that influence soil formation Describe some Important Properties of Soil • Soil profiles of distinct horizons that form as a result of weather combined with leaching • Soil can be categorized according to properties such as colour (composition), texture, structure, and pH Characterize the role of soils in Biological Cycling • Materials move from soil particles to soil solutions and back again by way of processes such as cation exchange • Soils play a crucial role in the nitrogen cycle by hosting free-living and symbiotic microorganisms that mediate nitrogen fixation, nitrification, and denitrification • Soils represent the largest terrestrial reservoir for carbon in the active carbon cycle – larger than all terrestrial vegetation and the atmosphere combined State the importance of soils for agriculture and in supporting plant growth • Soil is crucial for providing nutrients for plant growth and thus, for the support of life on Earth • Successful agriculture and a secure food supply require healthy soil • Soil properties affect (and may limit) the potential for plant growth and agriculture in any given location Identify the Causes and Predict the Consequences of Soil Erosion and Soil Degradation • As the human population grows, pressures from agriculture and other activities are degrading Earth’s soil, and we are losing topsoil from productive cropland at an unsustainable rate. • The main mechanisms of soil loss are splash, sheet, rill, and gully erosion by water, and deflation and abrasion by wind • Over-grazing, over-tilling, and careless forestry practices can cause soil degradation and negative impacts to native ecosystems • Desertification affects a large portion of the world’s soils, especially in arid regions • Over-irrigation can cause salinization and waterlogging, which lower crop yields and are difficult to mitigate • Over-application of fertilizers can cause pollution problems that affect ecosystems and groundwater Outline the history and explain the basic principles of soil conversion • T
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