ESSA01 Final Exam Notes PDF

lOMoARcPSD|47658804 ESSA01 Final Exam Notes Introduction to Environmental Science (University of Toronto) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Joanne Ye (joann...

lOMoARcPSD|47658804 ESSA01 Final Exam Notes Introduction to Environmental Science (University of Toronto) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 EESA01 Final Exam Notes Lecture 1: Introduction to Environmental Science Environmental Science How the natural world works How the environment affects us How we affect the environment. Environmental Science is interdisciplinary (has more than one component) across its 4 spheres Environmental patterns, processes, and human impacts across Earth’s atmosphere, hydrosphere, geosphere, and biosphere. Environmental Science Central Philosophy It has a hypothesis-driven approach to scientific understanding Formulates and tests hypotheses to derive objective/predictive knowledge about the natural and human-influenced world. Lab #1 Matter and energy Determine what the owl ate Make Calculations related to predator-prey energy transfer. Introduction to scientific numeracy, extrapolation, and allometry/biological scaling. Lecture 2: Matter, Energy, and the Sytems Approach to Environmental Science Learning Objectives Matter, the basics of chemistry Energy Systems Approach to Environmental Science Feedback loops Matter Anything that has mass and occupies space: solid, liquid, or gas Law of Conservation of Matter Matter may be transformed, but it cannot be created or destroyed Conservation of Matter in Environmental Science Helps understand Environmental processes and human impacts on the Environment Including pollution, chemical transport in the environment, and unintended Environmental consequences of production the total mass of any material system is neither increased nor diminished by reactions between the parts. Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Ex: The materials simply turn into gases you cannot see. When you bake, food seems to magically get larger. Expanding air bubbles caused the baked treats to expand, but more matter was not formed. Candles change form when they are burned. Atoms and Elements Atoms: The smallest components that maintain an element’s chemical properties Made of a nucleus with protons (positively charged particles) neutrons (no electric charges), and electrons (negative charges). Element: a fundamental type of matter, with a given set of properties. Elements in Environmental Science Mankind’s most astounding Environmental impacts are changes to the elementals made up of Earth’s spheres. These changes define the “Anthropocene” Epoch: a period of Earth’s ~4.6 billion year history defined by human impacts in the natural environment “Anthropocene” = Study of past human activity Ions, Cations, and Anions When atoms gain or lose electrons, they become ions. Anions (negatively charged) vs. Cations (positively charged). Water Molecule Polar molecule: negative charge at one end, positive charge at the other Leads to hydrogen bonding. Very strong cohesion: important for transport in plants Very high heat capacity: helps stabilize our climate A “universal solvent”: bonds well with other polar molecules Organic Compounds Organic Compounds: consist of carbon atoms, and usually hydrogen atoms. Carbon atoms are joined by covalent bonds (where the atoms share electrons). Often, organic compounds include other elements such as nitrogen, sulphur, oxygen, and phosphorus. Much biological matter is composed of organic compounds called hydrocarbons. Energy The capacity to change the position, physical composition, or temperature of matter A force that can accomplish work Potential Energy: energy related to the position Examples: chemical energy, nuclear binding energy, stored mechanical energy Kinetic energy: energy related to motion. Examples: solar energy, thermal energy, and motion. Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 First Law of Thermodynamics Similar to the “Law of Conservation of Matter” Energy can neither be created nor destroyed. The total energy in the universe remains constant and is “conserved”. For example, the potential energy stored in all the chemical bonds in a piece of firewood will be exactly equal to the thermal and light (kinetic) energy produced when the log burns. Or water turning into steam Second Law of Thermodynamics Heat will always flow from a HOT → COLD environment (not reverse) Entropy → Spontaneous (tendency to move from ORDER to DISORDER) In any transfer of energy, the nature or quality of the energy will change from a more ordered state to a less ordered state if no force counteracts this tendency. Systems tend to move toward increasing disorder (entropy). In every transfer of energy, some energy is lost but not destroyed. It simply changes into less usable forms. For example, as a dead log decomposes, it moves from organized and complex molecules to simpler, more rudimentary molecules. For example, 16% of gasoline powers a car to move forward, while the rest is converted to heat. Conversion Efficiency Example: If only 16% of gasoline powers a car forward, then energy efficiency (EE) can be stated as a fraction = 0.16. Let’s say there are 35 MJ (megajoules) per litre of energy in gasoline. How much gasoline energy (per litre) is used in propelling a car? Energy used to propel car forward = 0.16 x 35 MJ = 5.6 MJ How much energy is lost to heat and other forms of energy? Energy transformed to other forms = (1-0.16) x 35 MJ = 0.84 x 35 MJ = 29.4 MJ. Relating to the Lab In a food chain, organism A is eaten by organism B and organism B is eaten by organism C. Energy transfer or conversion “efficiency”: energy in organism A that accumulates in organism B is: Epred = Eprey * EEpred Example: if a prey animal constitutes 750 kJ of energy, but only 2.0% of that energy is “transferred” to the predator, how much potential energy accumulates in the predator? Epred = Eprey * EEpred Epred = 750 kJ * 0.02 Epred = 15 kJ Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Lecture 3: Matter, Energy, Systems, Approach to Environmental Science Learning Objectives Matter, the basics of chemistry Energy Systems Approach to Environmental Science Feedback Loops (ECO) System A “system” is a network of relationships among parts, elements, or components of the environment that interact with and influence one another, through the exchange of energy and matter. Ranging from very small to very large spatial scales (i.e related to space) and very short to very long temporal scales (i.e relating to time) Spatial Scales are the ratio between a distance on a map to the same distance in reality. A temporal scale is defined as a scale used to measure the change in a variable over time. It is also known as a "timescale." Geographers use different temporal scales to study various phenomena. Studying the change in temperatures as winter turns to spring, for example, would require one type of temporal scale. Open vs. Closed Systems OPEN systems: Receive inputs of energy and matter; produce outputs of both CLOSED systems: receive inputs of energy only; produce outputs of energy only Feedback loops Sometimes a system’s outputs also serve as inputs into the same system. This initial and final state is the same and is called a feedback loop Negative feedback loops: outputs from systems become inputs into a system; moving that system in an on-site direction (holds systems in equilibrium to make it more stable) Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Positive feedback loops: outputs from a system exacerbate the system response by moving it further toward one extreme (makes the system more unstable) In climate change, a feedback loop is something that speeds up or slows down a warming trend. A positive feedback accelerates a temperature rise, whereas a negative feedback slows it down. Resistance and Resilience ○ Resistance: the strength of an Environmental system’s condition or state to remain constant, despite environmental changes ○ Resilience: a measure of how readily an environmental system returns to its original state, following some type of disturbance ○ INSERT CHARTS Lecture 4: Ecosystems and Ecology Ecosystems and ecology Biogeochemical cycles Carbon Cycle Nitrogen Cycle Phosphorus Cycle Ecosystems and Ecology An ecosystem is a community of organisms and their physical environment interacting together. ○ you might find trees, rocks, birds, and bears ○ A place where things interact (habitats) Ecology is the study of organisms and how they interact with the environment around them. An ecologist studies the relationship between living things and their habitats ○ The study of interactions in the habitat The smallest ecology “self-sufficient” space. Energy and Matter Energy: entering an ecosystem is processed and transformed Matter: recycles within an ecosystem, resulting in outputs such as heat, water flow, and waste products Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Solar Energy → Biomass in Ecosystems Power from the Sun and only a fraction of this light energy can be converted to biomass (chemical energy) via the process of photosynthesis. Autotroph = primary producer: an organism that produces complex organic compounds from inorganic compounds. Sunlight (photoautotrophs) or oxidation of inorganic compounds (chemoautotrophs). Key Chemical Equations Photosynthesis: the process of transforming CO2 gas and water into energy: sunlight, carbon dioxide, water, glucose, oxygen Respiration: the use of accumulated carbon to produce energy (below is the aerobic process) (not breathing) Energy in an Ecosystem Gross primary productivity (GPP) refers to the rate of production of organic matter during photosynthesis. Net primary productivity : Net primary productivity (NPP) refers to the remainder of the gross production which is left after its use by the producers or plants in the process of respiration Gross Primary Production (GPP): Total conversion of solar energy into chemical energy by autotrophs. Net Primary Productivity: Energy remaining after respiration, that goes toward accumulating biomass Builds organisms wishing ecosystems This energy goes into accumulating biomass g of C per unit area per unit time g C/ m2/ year Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Factors Affecting NPP Ecosystems where the environment most favours plant growth will have the highest NPP. Favourable in this context refers to the presence of appropriate and sufficient conditions of sunlight, temperature, water, and nutrients. Any change in Earth’s spheres that impacts rates of photosynthesis and/or respiration, will ultimately impact global GPP and NPP Factors Affecting NPP: Nutrients Nutrients (especially macronutrients like nitrogen and phosphorus) can be limiting factors for productivity. Increases in these nutrients in a system generally increase NPP Nitrogen limitation is diagnosed when the addition of N results in increased NPP. Factors Affecting NPP: Temperature Photosynthesis and respiration are temperature-dependent processes Generally, ecosystem respiration rates increase with increasing temperature The assumption is that as climate change proceeds, soil temperatures increase. Resulting in greater soil respiration (experiences increases C emissions from soils) Reduces NPP + greater solid CO2 emissions = a Positive feedback loop. MOVES TO ONE EXTREME Factors Affecting NPP: Human Consumption We can add fertilizers to make plants grow bigger, and faster. We can also harm plants through deforestation, pollution, and forest fires, which can tarnish their soil and water. Humans are converting natural ecosystems into land uses with extremely high NPP Farming (Agriculture) NPP often exceeds what nature could “usually” support (pushes to one extreme) Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Biogeochemical Cycles ○ How an element—or compound such as water—moves between its various living and nonliving forms and locations in the biosphere ○ Earth is a “closed” system (because only energy is transferred outside the atmosphere) ○ Open to energy, but matter cycles (circulates) over and over again (matter cannot be destroyed) ○ Matter travels through Earth's spheres and systems continuously ○ From a biogeochemical cycle standpoint, “matter”, we are referring to elements such as C, N and P, or compounds such as water Matter circulates between pools or reservoirs ○ Pool collects, reservoirs is the rate of material moving ○ the atmosphere is an exchange pool for water. It usually holds water (in the form of water vapour) for just a few days. Part of a cycle that holds an element or water for a long period is called a reservoir. The ocean is a reservoir for water. ○ Volume of the material moving among reservoirs per unit time (a rate) is called flux ○ Fluxes (change) are not necessarily stable (ex: we have greatly affected the flux of C to the atmosphere) ○ Resident Time: the average amount of time a molecule or atom stays in a pool ○ Sources vs Sinks When demographic models take into account this habitat diversity (heterogeneity), the source-sink concept naturally emerges: a local demographic surplus arises in good quality habitats (source), and a local demographic deficit occurs in habitats of poor quality (sink). Global Carbon Cycle INSERT DIAGRAM Black text = reservoirs Blue numbers = reservoir size (Measured in Pg of C) Red arrows = fluxes Red text = transfer processes Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Red numbers = flux rate (Measures in Pg C/ year) Importance of Nitrogen 78% of atmosphere. 6th most abundant element on Earth. Key ingredient in proteins and DNA. Essential nutrient for plant growth. Relatively scarce element in the geosphere, hydrosphere, and biosphere. Fertilizers as a primary input of N fruit trees require an adequate annual supply of nitrogen for proper growth and productivity. Nitrogen is primarily absorbed through fine roots as either ammonium or nitrate. Nitrogen and plants and soils Plant available forms/ inorganic N in soil: – Ammonium (NH4+) – Nitrate (NO3-) Plant and animal wastes decompose, adding nitrogen to the soil. Bacteria in the soil convert those forms of nitrogen into forms plants can use. Plant unavailable forms: – gases including nitrogen gas (N2), ammonia (NH3), or nitrogen oxides (NOx) – Nitrite (NO2-) Key Process in the N cycle ○ Nitrogen Fixation: a combination of nitrogen ○ It is the process of nitrogen being converted to a usable form for plant consumption ○ gas (N2) with hydrogen to form ammonia (NH3) and subsequently, the biologically available ammonium anion (NH4+). ○ Two driving processes: lightning and nitrogen-fixing bacteria. Human Impacts on the N cycle ○ Doubling of N fixation: due to Haber- Bosch process (fertilizer production) + increased production of legumes (soybeans). ○ Increased atmospheric N2O (greenhouse gas) and other NOx (produce smog): due to fossil fuel burning + animal waste decomposition. ○ Major environmental impacts include acid rain, and eutrophication. Eutrophication Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 ○ It is the accumulation of lots of nutrients in lakes or other bodies of water increasing plant life on the surface ○ The process of nutrient over-enrichment, blooms of algae, increased production of organic matter, and ecosystem degradation Global Phosphorus Cycle ○ The biogeochemical cycle describes the transformation of phosphorus in soil, water, and living and dead organic material. ○ Key component of cell membranes, DNA, and ATP (energy). ○ Often limiting nutrients for autotroph growth. ○ The pools the P biogeochemical cycle are largely restricted to lithosphere and hydrosphere (NOT atmosphere). Human Alterations of the P cycle ○ Increasing organic matter in agricultural soils decreases runoff and provides phosphorus to plants. ○ Mining and using fertilizer ○ cutting down the rainforest ○ using the fertilizer changes some of the plants which causes the cycle to be unbalanced. ○ Weathered rocks release phosphorus, in the form of phosphate into the soil for plants to absorb. ○ Mining of phosphorus-bearing rocks for fertilizer production. ○ Wastewater/ sewage discharge. ○ Over-fertilization. ○ Use of phosphate detergents. Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Lecture 5: The Global Water Cycle Water on Earth (ch 11) ○ All life needs water to survive ○ Roughly 71% of the Earth is covered by water, but… ○ Only a very small proportion of Earth's total water is available for consumption ○ Fresh water= relatively pure, with few dissolved salts ○ Water may seem abundant, but drinkable water is rare ○ Only 2.5% of Earth’s water is fresh, most is tied up in glaciers and ice caps ○ EARTHS FRESH WATER DIAGRAM (on midterm) Water in the News ○ Water is subject to periods of scarcity and abundance ○ Considerable warnings in popular media and scientific reports about water shortages ○ From a North American perspective, seems highly localized ○ Evidence suggests this is happening globally The Water Cycle ○ The world’s water circulates in a “closed system” (stays inside of the atmosphere) ○ We’re not getting any more water from other places ○ The quantity of water on Earth will not diminish on shorter than geological timescales (i.e millions of years) ○ Instead, changes in water availability reflect changes in the hydrologic acid Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 The Hydrogen Cycle ○ hydrogen exchanges between biotic (living) and abiotic (non-living) sources and sinks of hydrogen-containing compounds Key Components of the Hydrologic Cycle ○ Evaporation: liquid to vapour ○ Transpiration: plants release vapour through their leaves ○ Precipitation: water falling from the sky ○ Infiltration: water enters into soil through the ground ○ Run-off: when there is more water than the land can absorb ○ Groundwater: water that seeps through rock and stays hundreds of feet below ground (like a well) Evaporation ○ Water changing from a liquid to a gas or vapour ○ Primarily water moving from oceans, Akers, and rivers, into the atmosphere ○ The main driver of the hydronic cycle accounting for roughly 90% of all water in the atmosphere ○ Globally, evaporation is roughly equal to precipitation Transpiration ○ Water released from plant leaves, into the atmosphere ○ Accounts for roughly 10% of all water in the atmosphere ○ Oceans through plant stomata Precipitation ○ A process where water vapor in the air, is changed into liquid water via condensation ○ Water first condenses into cloud form ○ Then falls back to earth as snow, rain ○ Occurs higher in the atmosphere, where temperatures are cooler and air condenses Infiltration ○ Precipitation that reaches the land surface, and enters into a soil ○ Primary source of ground water recharge ○ Depends on several factors including the amounts of precipitation, as well as soil texture Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Runoff ○ The portion of precipitation that appears in uncontrolled surface streams, rivers, or drains ○ Precipitation that does not infiltrate the ground, or percolate through soils ○ The total discharge of water overland Groundwater ○ Precipitation and surface water that soaks down through soil and rock ○ Into underground reservoirs called aquifers ○ Hold water for very long periods of time; groundwater recharge takes decades Water Balance or Change in a System ○ Inputs - Outputs = Change in Storage i. Inputs: Precipitation (P) (rain AND snow), maybe runoff (R), maybe groundwater flow (GW). ii. Output: Evapotranspiration (ET), runoff (R), maybe groundwater flow (GW). iii. Storage: Groundwater, soil moisture, lakes and reservoirs, rivers and streams. OVERALL: ○ P - ET ± R ± GW = ΔS ○ EX: A watershed that is 5 km2. ○ The annual volume of annual precipitation is 5,000 m3. ○ The annual volume of water that was evaporated was 400 m3. ○ The annual runoff (or loss of water out of the watershed) is 1200 m3 of water. ○ That groundwater flows out of, or into the watershed, are negligible. Then: Estimate the change in water storage in the system after one year. Answer: P – ET ± R ± GW = ΔS ○ 5,000m3 –400m3 –1,200m3 =ΔS ○ 5,000m3 –400m3 –1,200m3 =3,400m3 ○ ON MID TERM 4-5 CALCULATION QS Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Patterns of Water Use Shift in the Water Cycle ○ Major shifts occurring within many aspects of Earth’s hydrological cycle ○ Climate change impacts rates of evaporation, transpiration precipitation ○ Human consumption and pollution impact groundwater extraction and recharge, ○ infiltration; impacts on water quality LOOK BACK AT Diagrams Water Scarcity ○ All of these factors leading to unequal distribution/ scarcity of water resources among countries ○ And more common water shortages ○ Ideas exist that changing water availability influences human migration patterns and conflicts Bottled Water ○ Canadian’s use of bottled water only lower than U.S ○ Average per capita use is 2013 was ~68 L of bottled water ○ ~20% of Can. Households use mainly bottled water ○ Most bottled water is nothing more than tap water, sometimes with additional filtering or other treatment Pollution Major Environmental Issues ○ Arguably, if you think about major environmental issues, you likely think about climate change ○ As climate change proceeds, water pollution, and all the bad things that come along with it also continue apace. Freshwater Pollution ○ Water for human consumption and other organisms needs to be disease-free and non-toxic ○ Half of the world’s major rivers are seriously depleted and polluted ○ The invisible pollution of groundwater has been called a “convert crisis” Water pollution takes many forms Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Pollution: the release of matter or energy into the environment that causes undesirable impacts on the health and causes undesirable impacts on the health and well-being of humans or other organisms: Nutrient pollution Pathogens and waterborne diseases Toxic chemicals Sediments Thermal Pollution ○ Point source water pollution: specific locations of pollution (e.g factory or sewer pipes) ○ No points source water pollution from multiple cumulative inputs over a large area (e.g farms, cities, streets, neighbourhoods Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Lecture 6: Energy Inputs into the Earth Basics of Energy and Climate Climate-driven by energy fluxes, the balance between outgoing vs. Incoming energy A warm substance holds more energy than a cold substance If a warm substance becomes cooler, energy is leavening the substance (and vice versa) In a steady-state Earth, incoming energy equals outgoing energy over a year If this is not true, the Earth will either warm up or cool down Energy Inputs to Earth Earth receives all energy as income in solar radiation (“Insolation”) The rate (amount per time) of energy (Joules) received at a surface is called Power (J s-1) 1 joule per second is equal to 1 Watt (W) Power per surface area is an Energy Flux as is measured in W m-2 Insolation Fluxed on Earth Differs spatially leading to differences in energy inputs depending on location Differed temporarily leading to differences in energy inputs depending on the time of year Energy inputs to the Earth Since different parts of the Earth face the sun at different times of year, the area of highest radiation inputs changed through the seasons Short vs. Long Term mechanism Changes in Earth’s Balance Earth’s energy balance can change in multiple ways: ○ Increases in the amount of Insolation striking Earth ○ Changes in the amount of Insolation “trapped” on Earth ○ Changes in the amount of Insolation reflected by Earth Long vs. Short term mechanisms Long Term Changes Incoming solar radiation at a given place at a given time should change very little Over “geological” time periods (i.e 10 000s years) Called “Milankovitch Cycles” Related to Earth’s orbit around the sun Short Term Changes Earth’s balance of Insolation and outgoing radiation influenced by factors that humans can/have changed very quickly Albedo: dictated how insolation is reflected/absorbed Greenhouse gasses: dictate how outgoing radiation is trapped Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Albedo (light that is reflected from a surface) Earth reflects ~30% of insolation, and another ~70% is absorbed. ○ This reflectivity is termed albedo. ○ Albedo ranges between 0 and 1. ○ Related to a substance’s properties: snow has a high albedo (0.8-0.95), vs. asphalt with a low albedo (0.05-0.1). Implications of Energy inputs for climate change A major issue in Environmental Science What is causing climate change? Short-term changes: anthropogenic (human activity) climate change Long-term changes: “natural” climate change Evidence of Climate Change Searching for evidence of climate change means looking for climate anomalies Difference in present climate, compared to past trends in temperature or precipitation Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Lecture 7: Climate Change Predictions and Impacts Weather The conditions of the atmosphere over a short period (hours, days) Daily temperature, short-term precipitation, wind, humidity, wind chill, fog, UV index Climate Change Alterations to the way the atmosphere “behaves” over long periods Reductions in the predictability of atmospheric conditions over years (at minimum) IPCC (Intergovernmental Panel on Climate Change) The IPPC allows countries to analyze risks to their national plant resources and to use science-based measures to safeguard their cultivated and wild plants. Four Critically Important Agreements ○ Agenda 21 ○ Forest Principles ○ Convention on Biological Diversity ○ United Nations Framework Convention on Climate Change (UNFCCC) Key Points on Climate Change Predictions IPPC discusses “short-term” (2021-2040), “medium-term” (2041-2061), and “long-term” (2080-2100) climate change Predictions on climate always ○ 1. There is some uncertainty ○ 2. Because they depend on what we think will happen in the future Expectations of the Future Prediction of climate change, depending on predictions about greenhouse gas emissions Depend on laws, regulations, economics, human behaviour, ecosystem response to disturbances Different scenarios are captured as Shared Socio-economic Pathways” (or SSPs) A Snapshot of Well-supported Impacts Several major disruptions to Eeath’s spheres are occurring due to a shifting climate: ○ Sea ice loss ○ Rising sea levels ○ Changes in species composition ○ Increased prevalence of forest fires ○ Threats to food production/ security My Two Cents… Four Categories of Predictions 1. Likely: well-supported by scientific evidence, observations, and data Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 2. Possible: supported by reasonable hypothesis by limited evidence 3. Curious: who knows? Plus, these are often interesting 4. Climate change denialism: speculation masquerading as science Lecture 8: Biodiversity and Conservation What is Biodiversity: Assessed in three primary ways 1. Ecosystems diversity 2. Species diversity 3. Genetic diversity Ecosystem Diversity Number of different ecosystems, habitats, and environmental niches in a landscape The ability of organisms to interact with one another The critical concept for landscape-level conservation Genetic Diversity Genetic variation that exists within and among species Key in conservation biology, where conservation of different populations of the same species is the focus Critical in fields of agriculture and agroecology Species Diversity Number variety of species in the world or a particular location The main concept in conversation biology and environmental impact assessments Main policy-related interpretation of biodiversity (ex: conservation policy such as Species at Risk) Classification of Organisms: Biodiversity Systematics A classification system is needed to make sense of all biological species and understand relationships among them In biodiversity, classification is referred to as “systematics” A hierarchical system of organizing species ○ More families = more genera = more species ○ Fewer families = fewer genera = fewer species Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 How many species are there: Search to Count all Species on Earth Documenting the number of species on Earth is among the earliest scientific/ philosophical pursuits Aristotle (~350 BC): “How many organisms are there and how are they distributed around the world?” Measuring Species Diversity is Not Easy In the last 10 years, estimated ~ 8.9 million species across all different types of organisms The number is very difficult to estimate and is likely an underestimate Especially for things like insects and micro-organisms Specifies discovery: Species Discovered in the Past Few Years Generally, we continue to discover new species We are considered to be in an era of rapid biodiversity discovery Species Discovery Three primary reasons why species discovery continues and is incomplete: 1. Many species are tiny and overlooked 2. Some areas of Earth are little explored 3. Many organisms are difficult to identify Biodiversity on Earth Due to molecular studies performed in lesser-known ecosystems In the last two years, estimates of global species diversity have skyrocketed Biodiversity While species discovery continues at unprecedented rates Humans causing species declines and extensions at a pace not seen since dinosaurs went extinct (65 million years ago) Biodiversity Loss Terminology Extinction = occurs when the last member of a species dies and the species ceases to exist. Extirpation = disappearance of a particular population from a given area, but not the entire species globally. Endangered = species in imminent danger of becoming extirpated or Extinct. Threatened = species likely to become endangered soon. Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Mass Extinctions Events Losing ~75% of species, over a “short” period Earth has experienced five previous mass extinction episodes In the past 440 million years, mass extinctions have eliminated at least 50% of all species Due to cataclysmic, world-altering events Background Extinction Rates Background or “natural” extinction rates are based on the fossil record 2 out of one million species go extinct every year This is what we would “normally” except in nature Anything above these, are considered “elevates”. Towards Extinction Human activity is credited with an increase in extinction rates Things don’t just go extinct immediately Rather they slowly lead to major declines in species populations Ultimately may result in the extinction Species Conservation: Conserving Species Maintaining habitat (in situ conservation) Protect biodiversity and prevent species loss, by keeping people out The major role of government and NGOs in conservation biology is protected area establishment/enforcement Environmental change may be irreversible and protected areas are not enough to “save” species ○ Ex: Situ conservation includes preserving species in zoos, aquaria, seed banks, arboretums Captive Breeding: breeding and raising of individual species in zoos and botanical gardens with the intent of reintroducing them into the wild De-extinction: Bringing things back from extinction Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Lecture 9: Soils Soils in current environmental issues Why study Soil Science Soil is crucial to life on Earth, a key resource The environmental interface of minerals, air, water and living organisms Principle medium of plant growth, supplied food Recycles nutrients and water Key aspects of climate change and feedback Serves as an engineering medium Soil is a “system” A complex mixture of organic and inorganic matter, a wide diversity of organisms ○ Bacteria ○ Protists ○ Fungi ○ Invertebrates Larger things (Macroflora) Medium Size Things (Mesofauna) Smaller things (Microflora and fauna) Soil formation: What is soil? Dynamic natural bodies having properties from the combined effect of climate and biotic activities, as modified by topography (physical features of land), acting on parent material (rocks in which soil will form) over periods A specific spoil depends on where it came from: the soil-forming factors How do soils form? A slow and gradual transformation of rock (termed: parent material) into smaller and smaller pieces Change occurs due to mechanical or chemical weathering Physical/Mechanical Weathering Disintegration of rocks into smaller and smaller pieces ○ Temperature changes ○ Abrasion from wind, small particles in the air ○ Plants and animals Chemical Weathering Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Decomposition of rocks due to biogeochemical processes ○ Binding with water molecules ○ Exposure to oxygen ○ Exposure to acids from plants and animals Soils are highly variable and Diverse Soil forming factors are rather unique, depending on time and place in the world Weathering occurs in drastically different ways Leading to a wide diversity of soil types globally Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Soil Classification: Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Soil Classification: Chernozems Podzols Organic Soils Cryosol Soil physical and chemical properties: Classifying Differences Soils differ from one another based on four main abiotic characteristics: 1. Colour 2. Texture 3. Structure 4. Chemistry Soil Colour I. Soil colour is formalized II. Soil colour is determined by comparing a soil ped to a standard Munsell colour chart III. Colours assigned based on A. Hue - the dominant spectral colour B. Value - the lightness of darkness of a colour C. Chroma - the strength of purity of the dominant colour Soil Texture The physical size of particles in soils Defined as sands (largest), silt (medium size), and clays (smallest) The relative proportions/percentage of each of these are used to define soil textural class Soil texture triangle = a chart used to classify the makeup of various soils Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Soil Structure Arrangement of primary soil particles into groupings Aggregates or peds Can take multiple forms depending on theory arrangement, binding agents, textural classes ○ Spheroidal ○ Plate-like ○ Blocky ○ Prismatic Soil Chemistry Multiple aspects of soil chemistry are important, but two main aspects are: ○ Cation exchange capacity (CEC) ○ Soil pH Both are related to the ability of soils to absorb ions in soils Ions: Cations and Anions ○ Atoms that gain or lose electrons = ions ○ Anions (negatively charged) vs. Cations (positively charged) Cation Exchange Capacity Cation exchange capacity (CEC): a soil’s ability to hold onto cations Cations are plan available nutrients like K^+, Mg ^2+, Ca ^2+, NH ^4+, other cations CEC is roughly equivalent to soil fertility More negatively charged surfaces on soil particles mean more positively charged ions can be held Soil Management: Major Issues in Soil Sustainability Many current environmental issues centre on sustainable soil management Two key issues currently ○ Climate Change ○ Soil erosion/degradation and its links with food security Global Carbon Cycle (Soil) Soil represents the largest terrestrial reservoir for carbon Soil carbon fluxes are driven by rates of soil respiration and decay or organic matter These produce massive amounts of carbon dioxide and methane Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Soil Erosion and Degradation Net loss of soils (erosion), and reduction in soil fertility (degradation) are among human’s largest impacts on the environment Largely linked with intensive agriculture (and the multitude of things associated with it) Sustainable Agriculture and Food Security Alternative forms of agricultural management (or “sustainable farming”, take many forms) Organic production, non-GMO, fair trade, etc. Soil conservation is a major theme in all sustainable food production systems Crop Rotation Alternating crops grown in one field from one season or year to the next Intercropping Planting different types of crops in alternating bans or other spatially mixed arrangements to increase ground cover Contour Farming Plowing furrows sideways across a hillside, perpendicular to its slope, to prevent rills and gullies Terracing Level platforms are cut into steep hillsides, forming a “staircase” to contain water Shelterbelts Rows of tall, perennial plants are planted along the edges of the field to slow the wind Reduces Tillage Furroes are cut in the soil, a seed is dropped in and the furrow is closed Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Lecture 10: Agriculture and the Environment Agricultural Systems: Agriculture Agriculture exists on a spectrum across these characteristics Caution against making (or committing to an unquestioning trust in) broad characterizations Each category/ subcategory of agriculture is a subdiscipline Types of Agriculture Plant-based agriculture Animal-based agriculture Industrial agriculture Small-scale agriculture Organic agriculture Non-organic/conventional agriculture Traditional vs. Industrial Agriculture A Brief History of Agriculture: Agriculture and Human History Human history and population expansion intimately tied to agriculture Human populations and settlement patterns directly related to agriculture Begins with crop domestication and agricultural expansion, approximately 8,000 years ago Vavilovian Centers of Diversity Historically important areas where most crops were first domesticated Important for future agriculture: areas where new crop varieties might emerge The Green Revolution Modern agriculture is acknowledged as starting with the “Green Revolution” Major investments/ transformations in agriculture research and infrastructure Rise in pesticides, synthetic fertilizers, irrigation, energy use, and high-yielding seed varieties Extensification = bringing more land into production Intensification = better productivity per unit of land Purported benefits of the Green Revolution: ○ Yields rose as prices fell Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 Impacts of industrial agriculture: Agriculture is the key consumptive human activity for many of our natural resources Agriculture as a source of environmental issues surrounding: ○ Water ○ Greenhouse gases ○ Biogeochemical cycles (N, P, K) Water Use Agriculture primary water extraction and use industry worldwide Efficiency is quite low, only 43% of the water applied may be used by plants Lead to waterlogging and salinization of soils Irrigation strategies are key solutions Changes in Diet A narrowing of human diets post-Green Revolution: 90% of food comes from 15 crops and 8 livestock species The world is eating much more meat and seafood Raising livestock is very energy-intensive To meet demand, operations have been densified 45% of global grain production goes to feeding livestock Lose up to 90% of energy moving between trophic levels Some food production is more “efficient” than others The lower you eat on the food chain, the less energy, land area, and natural resources you require Human Impacts on the N cycle Doubling of N fixation: due to the Harber Bosch process (fertilizer production) + increased production of legumes (soybeans) Major environmental impacts include acid rain, eutrophication GMOs: Genetics Modification of Organisms and Recombinant DNA Genetic Engineering = laboratory manipulation of genetic material Creates a genetically modified (GM) organism Recombinant DNA = DNA patched together from the DNA of multiple organisms Biotechnology Biotechnology = Material application of biological science to create products derived from organisms Transgenic organisms = organism that contains DNA from another species Transgenes = the genes that have moved between organism Downloaded by Joanne Ye ([email protected])  lOMoARcPSD|47658804 GM Foods Globally 19 biotech “mega-countries” growing 50,000+ ha of biotech crops These nations are the world’s major food exporters 6 countries, 4 crops, 2 traits )herbicide tolerance and insect resistance) accounts for 99% of global area devoted to GM food Implications of GMO’s for Health, farming, and the environment Considerable concern over the health and environmental impacts of GMOs These effects are very difficult to measure or prove More immediate concern is over ownership of crop resources Further entrenching power of transitional companies Conservation of crop diversity, sustainable agriculture: Genetic Diversity Most industrial agriculture exists as monocultures: large single-crop or single-genotype paintings More efficient planting and harvesting Highly susceptible to disease and insects Require large inputs of fertilizers, irrigation, energy, pesticides, etc. Sustainable Agriculture Agriculture that aims to converse soils, water, and genetic diversity of crops No-till agriculture = ploughing and tilling are kept to a minimum to protect soils Low-input agriculture = pesticide, fertilizers, water, and fossil fuel energy are kept to a minimum Organic agriculture = absence of synthetic fertilizers, insecticides, fungicides or herbicides Seed Banks Climate change adaptation strategy to sustain future agriculture under climate change uncertainty Conservation of crop genetic diversity in seed banks Assuming current crop genetic diversity is critical for future agriculture Urban Agriculture Centering agriculture production in places where people love Reducing “food miles” Promotes conservation/cultivation of culturally-appropriate foods Minimized external applications 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