ENVS 1000 Intro to Environmental Science Notes - Systems and Global Change

Chapter 10 InQuizitive - Systems and Global Change: In terms of Earth’s systems, matter is considered a closed system and energy is considered an open system. Nitrogen-fixing bacteria are known as diazotrophs Nitrogen cycle ○ N2 in the air ○ Nitrogen fi...

Chapter 10 InQuizitive - Systems and Global Change: In terms of Earth’s systems, matter is considered a closed system and energy is considered an open system. Nitrogen-fixing bacteria are known as diazotrophs Nitrogen cycle ○ N2 in the air ○ Nitrogen fixation ○ Ammonification ○ Nitrification ○ Deniftrification ○ Nitrogen in the air populations of insects that are interdependent on other members of the population ○ social insect colonies active gas exchange with the environment ○ breathing cells that are combined hierarchically to form complex organisms ○ living organisms water molecules that are attracted to each other, shrinking the overall area of the water surface ○ surface tension Photosynthesis: The process characteristic of plants that uses water (H2O), carbon dioxide (CO2), and energy from the Sun to produce simple sugars and oxygen Which of the following are methods of carbon moving to the atmosphere from the biosphere? ○ via cellular respiration ○ through the action of methanogens ○ NOT Methods via photosynthesis through the action of burning fossil fuels Classify each of the following as an example of an open system or a closed system in relation to matter. ○ the circulatory system ○ a bowl of hot soup ○ glaciers ○ Closed ○ NOT Earth Analog watch Which of the following act as stocks for carbon in the carbon cycle? ○ atmosphere ○ living organisms ○ surface oceans  ○ NOT manmade structures fossil fuels Earth’s core A buildup of plants and algae results from the process of eutrophication. This process is caused by excessive amounts of nutrients, such as nitrogen and phosphorus, from manmade inputs found in fertilizer that are added to crops to enhance growth. Open systems ○ if we consider energy on Earth as a system and observe that energy on this planet comes from the Sun ○ if we consider water flow in the plumbing of a home as a system and observe that it is disrupted by a burst water main several blocks away ○ if we consider energy on Earth as a system and observe that no transfer of energy is perfectly efficient (that is, some energy is always lost as heat into space) Closed systems ○ if we consider matter on Earth as a system and observe the various stages of the rock cycle on Earth ○ if we consider matter on Earth as a system and observe biogeochemical cycles on Earth ○ if we consider matter on Earth as a system and observe the water cycle on Earth Although the air we breathe is nearly 80% nitrogen, we cannot use the form of nitrogen (N2) found in the air. Instead, we rely on the process of nitrogen fixation to convert N2 into a usable form. This occurs through the bacteria known as diazotrophs and the actions of a weather phenomenon known as lightning Reinforcing feedback ○ Microphones pick up sound from amplifiers and run that sound back through the amplifiers, causing an increase in the stock of loudness. ○ A growing population of flour beetles produces more eggs, which causes the population to grow even more. ○ Low oxygen levels in Biosphere 2 negatively affected the capacity of the scientists living there to do the labor required to grow and prepare food. As food production dropped, they were less nourished, and their capacity to work in turn decreased. Balancing feedback ○ The government places fishing restrictions on a fishery to give the fish population time to rebound. ○ As your temperature rises when you exercise, your body produces sweat in order to cool down. ○ You turn down a thermostat in a room that has gotten too hot. In a system, feedback that enhances the change of direction in a(n) stock is called reinforcing feedback, while feedback that counteracts the direction of change in a stock is called balancing feedback. True statements related to the phosphorus, nitrogen, and carbon cycles  ○ In terrestrial systems, phosphorus, nitrogen, and carbon must cycle through plants before becoming available to animals. ○ Phosphorus, nitrogen, and carbon are all important building blocks of biological molecules, such as DNA. ○ Humans have significantly altered the phosphorus, nitrogen, and carbon cycles. False statements ○ The rate of flow through the phosphorus, nitrogen, and carbon cycles is extremely slow, occurring over thousands of years. ○ In the phosphorus, nitrogen, and carbon cycles, the main element cycles through the atmosphere, the biosphere, the lithosphere, and the hydrosphere. How oxygen can move from the biosphere to the lithosphere ○ Marine organisms that produce calcium carbonate (CaCO3) die and sink to the seafloor, where they can eventually form limestone the process whereby bacteria and fungi break down nitrogen compounds in animal waste or dead matter and release ammonia ○ ammonification the conversion of ammonia to nitrogen compounds by ammonia-oxidizing microorganisms ○ nitrification the conversion of free nitrogen in the air to nitrogen compounds that plants, algae, and bacteria can take in and use ○ nitrogen fixation bacteria that possess an enzyme that uses nitrogen and hydrogen to produce ammonia ○ diazotroph the process whereby microorganisms use nitrogen compounds for respiration and create N2 gas, returning it to the atmosphere ○ denitrification Feedback: a loop in a system that responds to changes in stocks The only sphere that phosphorus does NOT cycle through is the atmosphere. Surface oceans serve as a stock for carbon, while deep oceans serve as a sink. Increasing levels of CO2 in the atmosphere have also led to increasing absorption of CO2 in the ocean, leading to a phenomenon known as ocean acidification. When CO2 combines with water, it forms carbonic acid. Over the past 50 years, the pH of the ocean has dropped, detrimentally affecting living organisms. Emergent property: an outcome arising from a system’s function as a whole Lecture 8 - 9/26/24 (​​https://canvas.upenn.edu/courses/1811845/files/138622587?module_item_id=3155688): Systems ○ Environmental systems are collections of components interacting with each other to produce outcomes that each component could not achieve on its own Biosphere 2  ○ In 1985, construction began on Biosphere 2, a 3-acre research facility in the Arizona desert built to be a self sustaining ecological system closed to outside material inputs and outputs ○ From 1991-1993, eight people called “Biospherians” lived in Biosphere 2 but required outside oxygen to survive. The designers failed to account for the complexities of oxygen exchange and nutrient cycling Matter is not created or destroyed, only changed ○ Law of conservation of mass states that matter cannot be created or destroyed Mass of constituent parts in a chemical reaction remains unchanged even as atoms involved in reaction are rearranged ○ First law of thermodynamics is that energy cannot be created or destroyed ○ second law of thermodynamics states that, with each transfer of energy, some energy is degraded and dissipates in form of heat What are systems? ○ Any portion of universe that can be isolated from the rest for purpose of observing and measuring changes, and that can produce outcomes that each component could not achieve on its own Ecosystems as open systems ○ Earth as a closed system ○ Earth is a dynamic system made up of many parts, including the land, ocean, mountains, clouds, streams, forests, animals, and humans Parts, interactions, and emergent properties ○ Human body is composed of ~25 elements ○ Elements combine to form molecules ○ Molecules combine to form cells ○ Each cell is its own mini-system Specialized parts work together to process matter and energy, store, and transmit genetic information, reproduce, etc ○ Cells form organs or parts of larger systems like the respiratory system ○ Emergent properties arise from function of a system as a whole How can we show how a system works? ○ Scientists use models, or simplified representations of real world, to show how certain aspects of a system function and interact  ○ Stock and flow diagrams show how matter or energy moves from place to place ○ Complex model simulations show things like environmental systems ○ Stock is a supply of something that we observe and measure over time ○ Flow is mechanism and rate by which a stock changes over time ○ Inflow increase stock, outflows decrease stock. If water is the stock in a bathtub, we can manipulate the faucet and drain to regulate the amount of water inside it ○ ○ Feedback ○ Systems generate outputs that influence their own operations ○ Feedback: loop in a system that responds to and produces changes in levels of stocks by affecting inflows or outflows of those stocks ○ Reinforcing or positive feedback Loop that responds to direction of change in stock by enhancing that same direction of change Further production in the system increases growth of system ○ Balancing or negative feedback Loop that counteracts direction in which a particular stock is changing Further production in system decreases growth of system Ecosystem stability and change ○ When rates of inputs and outputs are equal, and amounts of energy and matter within system are constant, system is in steady state equilibrium How do earth’s life support systems work? ○ Biogeochemical cycles: trace how matter on Earth flows through different parts of the environment, compartments, or “-spheres” Biogeochemical cycle shows complete path of a particular element “Bio” representing elements within living things (biosphere) “Geo” representing elements within nonliving parts of Earth, such as water (hydrosphere), air (atmosphere), and rocks (lithosphere)  Oxygen (O), phosphorus (P), nitrogen (N), carbon ( C), and sulfur (S), are macronutrients that organisms use in large amounts How do living things change the nitrogen cycle? ○ Triple bond holding nitrogen gas together takes a lot of energy to break, which makes it one of the most inert substances on Earth ○ Abiotic nitrogen fixation occurs through series of reactions powered by lightning, where nitrate ions fall to Earth’s surface in precipitation ○ Lightning strikes about 40 times each second on Earth, delivering about 13,000 tons of nitrate a day, which is less than 10% of nitrogen fixation on Earth ○ Some bacteria perform nitrogen fixation, where inert nitrogen gas (N2) in the air is converted to soluble ammonium (NH4) or nitrate (NO3) ions that plants, algae, and bacteria can use ○ Johanna dobereiner discovered nitrogen fixation fixing bacteria, diazotrophs, around certain kinds of plant roots. Rhizobium bacteria live in the roots of legumes, which are plants in the pea family. They fix nitrogen and provide needed ammonia to their host plants while utilizing sugars and protection in the root structure ○ Some bacteria and fungi use ammonification/mineralization to break down nitrogen compounds in anima waste products, as well as dead plant and animal matter, and release ammonia ○ Ammonia undergoes nitrification, where microorganisms convert ammonia to nitrate ○ Other microorganisms underground or underwater use nitrogen for respiration and return N2 gas to atmosphere via denitrification Carbon cycling through the biosphere ○ Carbon moves from biosphere to atmosphere as Co2 through decomposing microorganisms ○ Methanogens thrive in oxygen-free (anoxic) environments (wetlands, ot springs, hydrothermal vents in ocean, animal digestive tracts), release methane (CH4) into atmosphere ○ Cattle release CH4 from their guts through belching, flatulence, and defectaion Carbon cycling from biosphere to lithosphere ○ Some marine organisms combine calcium and bicarbonate to construct shells ○ When they die, calcium carbonate shells settle on ocean floor and become limestone, which over long periods of time is incorporated into CO2 rich magma that may be erupted back to the surface through volcanoes ○ Most significant impact on Earth’s carbon cycle is human use of fossil fuels, which take millions of years to form after exposure to high temperatures and pressure  ○ Reducing fertilizer pollution ○ Solutions to nitrogen and phosphorus pollution are: Apply fertilizer only at times of year when crops are most able to absorb them Minimize how often fields are tilled Lecture 7 - 9/24/24 (https://canvas.upenn.edu/courses/1811845/files/138519762?module_item_id=31528842): Air quality: refers to amount of gasses and small particles in atmosphere that influence ecosystems or human well-being Air pollution: refers to gasses or particles present in high enough concentrations to harm humans, organisms, or structures Indoor air pollution ○ Combustion by-products (CO, NOx, SO4, VOCs) from smoking, indoor burning ○ Construction materials (VOCs, asbestos) ○ Radon (naturally occuring gas) ○ Biological contaminants (viruses, fungal spores, bacteria) ○ Pesticides Pollution in the troposphere  ○ Natural sources ○ Natural sources produce greater quantities of pollutants than do human-made sources ○ Natural systems and species have adapted to natural “ingredients” of air, not introduced anthropogenic (human-caused) contaminants ○ concentrations are low, and inputs diluted immediately ○ Atmospheric dust transport ○ Wind at earth’s surface can sweep up particles and transport them great distances ○ Dust blown from mojave desert supports growth of pinon-juniper forests on Colorado plateau ○ Soot from forest fires in north america has traveled to greenland, where soot-blackened ice absorbs more heat and accelerates melting ○ Volcanoes can also release particles that attract and collect water droplets to cause rain, thunder, and lightning around the eruption area How does the atmosphere become polluted?  ○ We learned how matter is conserved, so when we burn wood, or fuel, matter doesn’t “go away”, instead, it changes form and persists as emissions in the atmosphere ○ Cars are major source of air pollution ○ Combustion engines emit carbon monoxide (CO), particulate matter (PM), and nitrogen oxides (NOx) to atmosphere ○ Effects of outdoor air pollution are influenced by atmospheric circulation patterns Primary pollutants ○ Primary pollutant: substance that is harmful in its directly emitted form ○ carbon monoxide (CO): colorless, odorless gas emitted in car exhaust from incomplete combustion CO accounts more than 50% air pollution by weight in US and world wide ○ ○ Particulate matter (PM): is made up of tiny particles and droplets less than 10 micrometers in size, suspended in air and can cause respiratory ailments Smallest particulate matter particles especially dangerous since they can be absorbed by lungs and enter blood stream  ○ Other examples of pollutants that make their way into atmosphere include: Volatile organic compounds (VOCs) from fossil fuels burning or using carbon-based compounds like paint or solvents Pesticides applied in agricultural areas Benzene released from gasoline production Asbestos from construction activities Toxic metals such as lead, mercury, and arsenic, which can travel in airborne particles Secondary pollutants ○ Secondary pollutants: products of reactions occurring in atmosphere ○ Smog: mixture of secondary pollutants, forms when VOCs and nitrogen oxides (NOx) from fossil fuel combustion interact with sunlight at warm temperatures As temperature increases ground-level ozone forms, which can damage lung issue in animals and damage chlorophyll in plants Air pollutants and tropospheric conditions ○ Thermal inversion: happens when warm air caps a cooler layer of air below, which prevents air circulation Results in polluted air becoming trapped over an area for an extended period Thermal Inversions  ○ Thermal inversion: happens when warm air caps a cooler layer of air below, which prevents air circulation Results in polluted air becoming trapped over an area for an extended period Place examples include: london fog and coyhaique, chile Political inertia What is happening to the ozone layer? ○ Stratospheric ozone: protects terrestrial life from ultraviolet (UV) radiation py preventing 99% of it from reaching Earth ○ Ozone layer sustains itself by splitting oxygen gas (O2) into oxygen atoms (O) in the presence of UV light, which then combines with another oxygen gasa molecule to form ozone (O3) ○ In 1970s, Lovelock, Rowland and Molina discovered that chlorofluorocarbons (CFCs) were reacting with stratospheric ozone and depleting ozone layer ○ UV radiation breaks apart CFCs, releases chlorine atoms, which react with and remove ozone at rate of 1 chlorine atom to 100,000 ozone molecules ○ Chairman of board of dupont quoted as saying that ozone depletion theory is “a science fiction tale…a load of rubbish…utter nonsense” ○ President of precision valve corp (inventor of aerosol can) wrote chancellor of UC irvine to complain about rowland’s public statements ○ 1995 nobel prize for chemistry ○ Stratospheric ozone showed a steady decline throughout the 1970s and 1980s, with satellite images confirming ozone layer was thinning ○ Highest level of depletion was occurring over antarctica during spring season, with discovery of an ozone hole showing 50% reduction ○ Area below ozone hole, amount of UV radiation can be double annual average, with increased incidences of skin cancer and cataracts ○ Global response was adoption of 1987 montreal protocol to phase out CFCs Why antarctica? ○ If bulk of CFC production is in northern hemisphere, why is ozone hole over antarctica? Near circular high pressure system isolates atmosphere over antarctica in winter As long as temperatures remain < -55 degrees C, reactions that destroy ozone will occur Result is concentration of ozone-depleting chemicals and conditions at south pole As temperatures warm, ozone formation outpaces destruction ○ Ozone depletion has also been observed about north american and europe, but much less (10% vs 70%) What is acid rain? ○ Normal rainwater is slightly acidic, with a pH of 5.6 ○ In 1970s, rising sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions were reacting with water vapor to form sulfuric acid (H2SO4) and nitric acid (HNO3)  ○ Acid created from these pollutants then precipitates, known as acid deposition, or “acid rain” ○ Acid deposition has changed pH of thousands of lakes in eastern Canada and new england, altering ecology ○ Acid deposition also affect soil pH and important soil microbes that affect plant growth and mortality ○ Acid deposition also wears away human structures and artwork, especially ones made of limestone and marble How are we responding to pollution in the atmosphere? ○ Policy strategies addressing air pollution in united states have been successful even as country experienced increased population and economic growth ○ Clean Air Act of 1970 established two important standards for more than 70 categories of polluting industries such as agriculture, manufacture, and utilities ○ Emission standards required new and upgraded facilities to reduce smokestack pollution ○ ○ Under clean air act, EPA assesses health risk for common pollutants to determine maximum allowable concentrations of each ○ These concentrations form National Ambient Air Quality Standards (NAAQS), which are measured and monitored for compliance to report “bad air days” for sensitive populations ○ Energy Policy and Conservation Act (1975) empowered Department of Transportation to set minimum miles per gallon (mpg) standards ○ Now known as corporate average fuel economy (CAFE) standards ○ Apply to cars and light trucks  ○ ○ 1990 amendments to clean air act of 1970 added new policy strategy, tradable emission allowance, where EPA sets total allowable annual emissions for a pollutant from utilities, then divides this total into tradable units called allowances, which are bought and sold ○ Each facility’s annual emissions must stay at or below allowance to remain in operation ○ If facilities want legally exceed this level, they can buy additional allowances from those who have not used their full allowance ○ EPA estimates cumulative benefits related to improving public health and reducing lost workdays exceeds $2 trillion ○ International air pollution policy Agreements to limit air pollution among countries Driven by shared sense of need and cost sharing ○ Geneva convention on long-range transboundary air pollution (1983) ○ Montreal protocol (1987( ○ 1999 protocol (acidification, eutrophication, and ground-level ozone) Chapter 8 InQuizitive - Air: Atmosphere ○ A dynamic envelope of gases extending up from Earth’s surface that clings to our surface due to gravity Primary pollutant examples: ○ Carbon monoxide ○ Nitrogen dioxide (NO2) in 1 hour ○ sulfur dioxide (SO2) in 1 hour ○ particulate matter ○ Volatile organic compounds (VOCs) Secondary pollutant:  ○ Particle pollution (PM2.5) after 1 year at 15 mug/m^3 ○ smog Policy strategy that uses a market approach to confront air pollution ○ Tradeable emission allowances address sulfur dioxide emissions from coal-burning power plants Lake or land effect ○ Mountains force air masses upward, leading to precipitation ​Rising barometric pressure indicates increasing air pressure, whereas falling barometric pressure indicates low air pressure. A high-pressure system tends to be associated with clear and dry conditions and contain cooling air that is denser and heavier. A low-pressure system is often an indication of cloudiness and an increased chance of precipitation. Nitrogen makes up the largest share of the atmosphere Characteristics of Ozone: ○ Ozone absorbs 99% of the UV radiation from the Sun. ○ Ozone near the ground forms smog ○ Not characteristics of ozone: Ozone can split a chlorine atom to form oxygen. Ozone is taken up by plants. High pressure systems tend to be associated with clear and dry conditions Examples of Tradable Emissions Allowances ○ The EPA has set the total allowable annual emissions for SO2 from the Navajo Coal Power generating station in Arizona. However, the coal power plant has exceeded its annual emissions. The only way it can legally exceed this level is to buy additional allowances from other utilities companies that are below their limits. ○ A trash collection agency has exceeded its allowable annual emissions set by EPA as it burns trash in an old incinerator. The only way it can operate is to buy additional allowances from the recycling agency that is below its limit. Not Examples of Tradable Emissions Allowances ○ Consumers can trade their old SUV for a new electric car and get a rebate. ○ The EPA mandates fuel-efficiency labels for automobiles and gives hybrid and electric cars a clean label. To occur with persistent acid rain in an area ○ Acid deposition changes soil composition and limits tree growth. ○ Acid deposition lowers pH levels in lakes, affecting the developmental stages of both insects and fish. ○ Incorrect answers: Acid deposition preserves artworks made of marble. Acid stops leaching into groundwater. Large bodies of water heat up and cool down slowly, causing coastal areas to heat up and cool down more gradually than does land far from the sea air in motion as it flows from high-pressure to low-pressure areas ○ wind  a measure of the pressure exerted by Earth’s atmosphere at a given point ○ barometric pressure a warm air mass replacing a cold air mass ○ warm front the amount of water in a given volume of air ○ humidity a cold air mass replacing a warm air mass ○ cold front contains cooling air that becomes denser and heavier, sinking to form areas that are typically depicted as big Hs on weather maps high-pressure system Clean air act ○ Federal law established air quality standards and regulations on the source of pollutant The equator receives more of the sun’s energy per unit of surface area than other latitudes Relative humidity: the maximum amount of water that the air can hold at a given temperature Air pollution results from various causes. Sometimes local temperature and landforms can trap pollution over a particular area. In normal conditions, air is warmer near the surface and cooler at high altitudes. However, at certain times, a layer of warm air caps a cooler layer of air below, creating a phenomenon known as thermal inversion Air pressure: ○ Air gets “thinner” at increasing altitudes as the gas molecules are more dispersed. ○ All gases, including air, move from areas of high pressure to areas of low pressure. ○ The air high above the ground weighs down the air closer to Earth’s surface, causing the pressure to be higher down below. ○ Not air pressure Mountaineers who climb to altitudes above 26,000 feet struggle to breathe because the high air pressure forces the air from their lungs. All gases, including air, move from areas of low pressure to areas of high pressure. Pressure is the amount of volume a gas fills. Stratosphere ○ Pollution and ash from volcanoes make their way to the stratosphere. ○ The stratosphere has an abundance of ozone, about 1,000 times more than near the ground. ○ Not stratosphere Most meteors that reach Earth’s surface burn up in the stratosphere. In the stratosphere, large amounts of water vapor condense and form clouds. Lecture 6 - 9/19/24 (https://canvas.upenn.edu/courses/1811845/files/138343921?module_item_id=31511051): What is weather and how does it change? ○ Weather: refers to short-term variations in atmospheric conditions such as temperature, moisture, and wind Different from climate (which is a long-term average of weather conditions) National weather service defines climate for particular region using a 30 year average of regional weather conditions Pressure: force exerted on or acting against something ○ Pressure in a balloon can be increased by Adding more air Compressing the balloon Increasing temperature of air in balloon ○ All of which cause internal gas molecules to bump into walls more frequently ○ Imagine a cylinder of air extending above Earth’s surface ○ Weight of air at top of the cylinder presses down on lower layers of air, forcing lower molecules closer together and increasing the atmospheric pressure ○ As air moves farther away from Earth’s surface, molecules move farther apart, pressure decreases, air becomes less dense, or “thinner” ○ How is Earth’s Atmosphere Structured? ○ The atmosphere is divided into four layers with different pressures, temperatures, and composition Around 100 kilometers ○ Most of the atmosphere’s mass is within a 5 to 19 mile thick layer above Earth known as the troposphere  ○ The next layer, extending 30 miles above the troposphere, is the stratosphere, which contains the ozone layer ○ The next layer, the mesosphere, lies above the stratosphere and has the coldest temperatures, has the coldest temperatures, which fall as low as -148 degrees Fahrenheit ○ Thermosphere, above the mesosphere, which is warmer due to solar and cosmic radiation, and less dense due to low levels of gravity ○ Temperature ○ Temperature variations across Earth’s surface are mostly due to changes in amount of radiation received at various latitudes ○ Land and water features also affect temperature variations Water vapor ○ Precipitation, humidity, and cloud cover reflect the amount of water vapor in the air, as water constantly moves into and out of the atmosphere through evaporation and condensation ○ Humidity: the amount of water in a given volume of air and can greatly affect the rates of evaporation ○ relative humidity of air: the amount of water in the air as a percentage of the maximum amount of water that the air can hold at a given temperature Atmospheric stability ○ ○ Diabatic process: temperature change when energy is added or removed from a system Ex: pot of water placed on a stove warms diabatically ○ Adiabatic process: temperature changes, but no heat is added or removed ○ ○ Dry adiabatic lapse rate (DAR): rate at which rising parcel of unsaturated (dry) air cools, ~10 degrees celsius/1000m ○ If a parcel of air rises high enough, expansion lowers temperature to dew point (temperature @ 100% relative humidity) ○ As saturated air continues to rise, cooling is partially offset by release of latent heat of condensation ○ Moist adiabatic lapse rate (MAR): rate at which saturated air cools, ~6 degrees celsius/1000m but varies with temperature  ○ Lapse rate is bigger than cools number ○ Barometric pressure ○ Air masses: large volumes of air typically several kilometers thick and a thousand or more kilometers wide that have relatively uniform temperature and humidity ○ High-pressure systems: masses of cooling air that becomes denser and heavier, causing them to sink and form areas of high pressure; usually associated with clear, dry conditions When air masses warm, molecules expand to form low-pressure systems where warm, rising air cools as it expands into higher and colder altitudes ○ Cold air sinks ←→ high pressure ○ Warm air rises ←→ low pressure Weather ○ Fronts form at boundaries between high-pressure systems (cold air masses) and low-pressure systems (warm air masses) ○ Cold front: cold air mass replacing warm air mass  ○ Warm front: warm air mass replacing cold air mass In extreme weather situations, low-pressure systems can pull air from other places, creating hurricanes and typhoons ○ Frontal systems: How does the atmosphere circulate? ○ Wind is air in motion, flowing from high to low pressure ○ Regular global patterns of air circulation are driven by Earth’s rotation and differences in temperature between equator and poles ○ Equator receives Sun’s rays most directly, large body of warm and humid air known as equatorial low pressure belt, supplies abundant precipitation ○ As warm air rises, cools, spreads, north and south, descends, and creates patterns of increasing atmospheric pressure known as subtropical high pressure belts ○ Subtropical high-pressure belts cause arid conditions at midlatitudes north and south because of descending air  ○ After reaching equator, air has warmed again and rises, creating a looping weather pattern that forms circulation systems between the equator and latitudes 30 degrees north and 30 degrees south, called Hadley cells ○ Ferrel cells also form between latitudes 30 degrees north and 60 degrees north and 30 degrees south and 60 degrees south, with polar cells forming higher latitudes Patterns of atmospheric pressure and prevailing winds ○ Due to coriolis effect (rotation of Earth), prevailing winds from Hadley and Ferrel cells are bent ○ In northern hemisphere, air bends clockwise around H and anti clockwise around L ○ prevailing wind patterns called jet streams form near the top of troposphere where Hadley, Ferrel, and polar cells meet What makes up the air we breathe and our atmosphere? ○ Air is a mix of many gases ○ Earth’s atmosphere contains: 78% nitrogen 20% oxygen Smaller amounts of argon, carbon dioxide, water vapor, and other compounds ○ These gas atoms and molecules continually bounce around, collide, and fill whatever space or volume is available Evolution of atmospheric composition ○ Earth’s atmosphere was initially devoid of oxygen ○ As earth cooled, water condensed, rained, removing Co2 and produce oxygen ○ Oxygen accumulated in oceans but not in atmosphere until ~2.5 billion years ago Chapter 5 InQuizitive: edge effects: the conditions occurring where two or more habitats meet. ○ Expected to increase: predation, sunlight exposure, wind exposure ○ Expected to decrease: humidity Services: ○ provisioning services fisheries ○ regulating services crop pollination provided by wild bees, birds, and bats ○ supporting services Earth processes that govern the nutrient cycles (such as nitrogen, phosphorous, and carbon) and the availability of water ○ cultural services a wilderness area where some groups practice religious ceremonies Protecting biodiversity ○ extractive reserves:  a community-based conservation strategy that enables people who have traditionally depended on protected areas to continue using them in sustainable ways ○ payments for ecosystem services: payments to landowners to compensate them for conserving resources that provide benefits to the surrounding area ○ land trusts: non profit organizations that purchase lands for conservation ○ tradable development rights: payments to landowners who forfeit the right to develop in certain areas ○ wildlife corridors: protected areas of land that connect other protected areas sustainable forest management strategy: ○ Leaving large patches of dead trees, tall trees Ecosystem services can be provisioning, regulating, supporting, or cultural services Characteristics of the Endangered Species Act ○ The act makes it illegal to directly and intentionally harm endangered species through activities such as hunting and trapping. ○ The ESA only protects species whose populations are so low that they are threatened with extinction or in danger of becoming extinct. ○ The ESA has been successful in increasing the population numbers of 21 species enough to where they have been removed from the list. Not Characteristics of the Endangered Species Act ○ The act can be enforced internationally. ○ The ESA is an international agreement banning the hunting, capture, and selling of endangered and threatened species. ○ The ESA is a treaty between the United States and Canada that exclusively protects migratory birds. ecological island effect ○ Such threats include increased vulnerability to disease, inbreeding within the area, and the risks that lie just outside the boundary like hunting or vehicle traffic on roads. Two strategies to address this situation are buffer zones around the protected areas that limit the most destructive human uses and wildlife corridors that allow protected passage from one protected area to another. True Statements about Captive Breeding Programs ○ The goal of these programs is to restore the population and reintroduce the species back into its original habitat. ○ If the captive population is small, lack of genetic diversity can decrease the species’ fitness. ○ These programs are expensive and often have a low chance of success. False Statements about Captive Breeding Programs ○ The captive populations are always fit for life in the wild. ○ They are only used for large animals. ○ Chapter 7 InQuizitive (Water): impervious surface ○ Surfaces through which water cannot drain through Lakes and ponds host lentic ecosystems, which have relatively still water in zones defined by distance from shore and penetration of sunlight. Rivers and streams, on the other hand, host lotic ecosystems, which have different habitats created by variations in their flows, ranging from turbulent rapids to relatively still pools. Different types of water pollution include sediment pollution caused by loose soil particles swept into waterways, chemical pollution in which lead can leach from old pipes and plumbing fixtures, and biological pollution where disease-causing microorganisms are carried into freshwater sources. Wetlands ○ An area where the ground is seasonally or permanently saturated with water Ensuring reliable access to safe and affordable water or water security for everyone is one of the sustainable development goals of the United Nations (UN). The shallow-water littoral zone near shore tends to host the greatest quantity and diversity of organisms. Here, plants that can root into the bottom, such as cattails, thrive. Farther out in this zone, floating plants such as water lettuce and submerged plants such as pondweed establish themselves. These plants host snails, dragonflies, insects, and small fish. ○ Well beyond the shore, the pelagic zone is further divided based on the extent to which sunlight penetrates the depths. Rainwater harvesting is one of the ways to conserve water that would otherwise become runoff into rivers or streams. Rainwater-harvesting structures channel water from runoff to underground cisterns where the water can be stored for use during times of water scarcity. Safe drinking water act ○ federal regulation requires the Environmental Protection Agency (EPA) to identify the contaminants in water and set maximum allowable levels for each contaminant based on the agency’s analysis of the health risks Albedo ○ a measure of the reflectivity of a surface Cryosphere ○ the frozen part of Earth’s crust Permafrost ○ water perpetually frozen in soil or rock sea ice ○ frozen ocean water that is usually seasonal Point Source Pollution ○ a pipe with water flowing out of a sewage treatment facility ○ a pipe directing raw sewage into a waterway ○ a system that takes water into a factory for a cooling process and returns it to its water source Non point source pollution  ○ airborne pollution that is carried by the wind and settles in a distant lake ○ runoff from a farm into a nearby lake ○ runoff from a suburban area into a nearby stream main contributor to ocean dead zones ○ Low oxygen caused by agricultural runoff Methods to conserve water ○ fixing leaky and cracked pipes ○ water recycling ○ switching from flood irrigation to drip lines ○ planting drought-tolerant plants Non methods ○ growing crops such as citrus and avocados ○ irrigating plants by sending water through water channels communities of life hosted by rivers and streams ○ lotic ecosystem rivers, streams, lakes, ponds, and wetland areas ○ surface water communities of life hosted by lakes and ponds ○ lentic ecosystem places where groundwater accumulates, saturating cracks and pores of material above a dense layer that it cannot pass through ○ aquifer the total of all the water reservoirs on Earth ○ hydrosphere False ○ Surface water withdrawals and diversions enhance ecosystems by stopping the flow of nutrient-rich sediments and the flow of streams. location of about.001% of Earth’s water with an average residence time of about 10 days ○ atmosphere Earth’s largest reservoir of freshwater ○ cryosphere Earth’s largest reservoir of water ○ oceans Earth’s largest reservoir of liquid freshwater ○ groundwater ecosystem with still water ○ lentic ecosystem type of area that includes swampy peat bogs ○ wetlands wetlands where plants can survive high water salinity ○ estuaries ecosystem with flowing water ○ lotic ecosystem  The construction of these often results in waterways being dredged, straightened, and built up with levees. ○ man-made channels These block the migration of fish. ○ dams These move runoff quickly to storm drains, carrying with them pollutants and increasing the peak flows of rivers. ○ impervious surfaces Water behind a barrier here traps sediment and increases the evaporation rate. ○ reservoirs behind dams Although groundwater is a(n) renewable resource, the recharge time for groundwater often exceeds 10,000 years, which means that resupply can lag far behind the human withdrawal rate. Some aquifers are even sealed off by surrounding rock, preventing precipitation from infiltrating through the ground. This “fossil water” can have a residence time of millions of years. Withdrawals from such reservoirs that are not renewable are called water mining. Eutrophication order: ○ fertilizer runoff from fields into water systems ○ high nutrient availability causing algae growth to spike ○ eutrophication ○ Lecture 5 - 9/17/24 (https://canvas.upenn.edu/courses/1811845/files/138235164?module_item_id=31486047): Water quality: measure of suitability of water for particular use based on selected physical, chemical, and biological characteristics Water pollution: any change in water quality that adversely unsuitable for desired uses Sources of water pollution: ○ Point sources: contaminants from a clearly identifiable conduit such as a pipe, ditch, channel, or well Under clean water act, anyone discharging pollution needs a permit ○ Nonpoint sources: pollutants from broader, diffuse, and less readily identifiable places such as agricultural, residential, and industrial activities Total maximum daily load (TMDLs) represent maximum amount of pollutant in water before quality is reduced EPA requires states to report impaired waters that surpass TMDLs Water pollution: ○ Physical pollution is a change in the physical properties of the water itself to a level that harms ○ Chemical pollution is the dilution or transport of a substance that can cause harm ○ Biological pollution is the transport of an organism that can cause harm  Pathogens - Water Pollutants ○ Human wastewater can contain a variety of illness-causing pathogens ○ Not feasible to test for all, use indicator species instead: fecal coliform bacteria ○ Water sanitation: process of cleaning and purifying water so it is safe for use Oxygen demand - water pollutants ○ Microorganisms in water use organic matter as “food” and thus consume oxygen ○ Biological oxygen demand (BOD): amount of dissolved oxygen (DO) used by microorganisms in the biological process of metabolizing organic matter in water ○ Well-aerated water contains 9 mg/L (ppm) dissolved oxygen ○ Fish will die when DO < 2-3 mg/L ○ If DO = 9 mg/L only anaerobic bacteria can survive ○ Ex: 1. Sample pipetted in BOD bottle DO content is determined Bottle is incubated in dark for five days at 20 degrees C Difference between final and initial DO reading is calculated, and represents BOD of sample ○ Many sample have BOD higher than amount of oxygen available in BOD bottle ○ Samples must be diluted, eg use of 5 ml of sample and fill rest of the bottle with clean water ○ BOD = (IDO - FDO)/(VS/VB) = (DO initial - DO final) over (volume of sample over volume of bottle) Nutrients - water pollutants ○ Some inorganic chemicals carried in all bodies of water are nutrients - essential elements required by plant (N, P) ○ Oligotrophic: water under low concentration (water is clear) ○ Eutrophication: excessive nutrient inputs (commonly P in freshwater, N in marine water) may lead to ecological imbalance of production ○ Natural process augmented by human activity ○ Origins of excess phosphorus in freshwater systems: Erosion of soil from agriculture and forestry Treated effluents and storm drainage Sodium tripolyphosphate (detergents) ○ Origins of excess nitrogen in marin system: Agricultural fertilizers are the main source Atmospheric deposition of fossil fuel emissions Eutrophication of surface water ○ Cyanobacteria (blue-green algae): takes greatest advantage of nutrient enrichment Some of these are harmful to humans and animals Toledo, ohio had its tap water supply shut down for >400k people in 2014 bc the water was too toxic to drink Lead - Water pollution  ○ To reduce costs while waiting for new pipeline, city of Flint, MI, changed water source to Flint River instead of Detroit River Due to differences in pH, new water source caused lead to be released from pipes and plumbing fixtures and led to dangerous levels of lead in water sampled from homes and schools How do we keep freshwater clean? ○ Wastewater comes from various sources Sewage Sinks and other household uses Stormwater runoff Manufacturing and industry Electricity generation ○ Historically dumped into waterways ○ Developed countries now treat wastewater before discharge How do we keep freshwater clean? ○ There are 164 combined sewer outfalls (CSOs) along Delaware and Schuylkill rivers and Cobbs, Tookany/Tacony-Frankford, and lower Pennypack creeks ○ Unfortunate side effect of preventing flooding by allowing CSOs to discharge is contamination and erosion of waterways ○ Waterways where CSO is overflowing is unsafe for recreation, and may remain unsafe for 72 hours following storm events ○ State and federal regulations, including sections of the Clean Water Act, require Philadelphia to reduce at least 85% of this pollution (or face steep fines) ○ Philadelphia’s green city, clean water program was launched in 2011 to help manage stormwater and reduce combined sewer overflows (CSOs) ○ Government regulates water quality through Safe Drinking Water Act and Clean Water Act ○ EPA identifies contaminants and sets maximum allowable level, but requires state enforcement ○ Clean Water Act focuses on surface waters and point sources ○ Most pollution comes from nonpoint sources ○ Regulation of nonpoint source pollution left up to voluntary measures or limited state laws ○ Regulating water quality 1948: Water Pollution Control Act (rewritten 1972) 1972: Clean Water Act (CWA) 1987: Water Quality Act Requires EPA to develop criteria for ambient water quality Criteria grouped: aquatic life, biological, human health, microbial/recreational, sediment 167 criteria pollutants Criteria maximum concentration (CMC) and criterion continuous concentration (CCC) Why is frozen water important?  ○ frozen parts of Earth’s surface up cryosphere ○ Along with snow, ice, and glaciers, cryosphere also includes permafrost and sea ice ○ Melting of sea ice contributes to global warming, since ice has a higher albedo, which helps cool the planet ○ Loss of glaciers causes sea level rise as fresh water flows into ocean As ice sheets melt, ocean currents are disrupted and influence global climate change Glaciers and water resources: ○ Glacierized basing cover 26% of global land surface area outside of Greenland and Antarctica ○ >30% of the world’s population ○ Upland areas of SE Asia supply five basins of the Indus, Ganges, Yellow, Brahmaputra, and Yangze rivers ○ drinking water to > 20% of world’s population How does the ocean support life? ○ Neritic zone: shallow water area just above continental shelf; sunlight leads to abundance of phytoplankton (algae), which provide food for shrimp, jellyfish, snails, and small fish Chapter 4 InQuizitive: Commensalism: An orchid uses a tree limb as a surface for growth but does not draw resources away from or harm the tree. Speciation: Subsets of a population diverge genetically such that they can no longer produce fertile offspring when they breed. K-strategist species: ○ Large size: K-strategists are often large organisms. ○ Long life expectancy: K-strategists have longer life expectancies. ○ Fewer offspring: K-strategists produce fewer offspring than other organisms. ○ More parental care: K-strategists invest more in each of their offspring, often providing extensive parental care until they mature. ○ Higher survival rates: K-strategists have higher survival rates for their offspring. ○ Stable environments: K-strategists are typically found in stable, mature environments. Biodiversity hotspots are areas with relatively high densities of endemic populations that specialize in a particular set of environmental conditions. Adaptive radiation is an evolutionary process by which many generations of a(n) ancestral species diversify, producing a variety of new species adapted to new niches in an ecosystem. EX: Polar bears act as keystone species since they prey on seals, which in turn affects the impact of seals on fish populations. Removing polar bears would increase seal populations dramatically, and the fish population in the area would soon considerably decrease. Lecture 4 - 9/12/24 (https://canvas.upenn.edu/courses/1811845/files/138049789?module_item_id=31467804): Where on Earth is all the water? ○ Water moves through reservoirs, or parts of Earth where a material remains for a period. (Reservoir is also a term for an artificial water body behind a dam) ○ Reservoirs constitute Earth’s hydrosphere, which are all the places that hold water on Earth Ocean Glaciers Groundwater Atmosphere Surface water (lakes, rivers) ○ Average residence time is time a molecule spends in a reservoir Precipitation that reaches land follows two basic pathways: ○ Overland flow ○ Infiltration (soaking into soil surface), followed by percolation (further vertical movement) Of water going from land to ocean, ~90% comes from overland flow and only ~10% from groundwater ○ But… much more groundwater than surface water by volume Groundwater: ○ Porosity: proportion of a material made up of spaces ○ Permeability: capacity of water to flow through pore network Ex: rocks that have large, well connected pores have high permeability ○ Groundwater flow rates: Much slower than water in streams Rapid groundwater flow through sand and gravel is 10m day Can be as slow as 1-10cm day ○ drinking water wells 40-60m (140-200 ft) deep Surface water: drainage basins ○ Drainage basin: is an area of land where water from rain or snowmelt drains into a river, lake, wetland, or ocean ○ Drainage divides: are lines along high ground that control into which basin water drains into ○ Ex: delaware river basin Headwaters in catskill mountains in upstate NY Area = 33060 km^2 River length = 595 km Discharges to atlantic ocean Provides water for 20 mil people, many outside the basin ○ Ex: Schuylkill river basin Upper portions ridge and valley appalachian mtns Area = 5180 km^2  Length = 217 km Discharges to delaware river leni lenape settlement, nittabakonck (“place where heroes reside”) Dutch name: schuilen, kil Surface water: lakes and ponds ○ Lentic ecosystem: an ecosystem in a lake, pond, or other relatively still water Surface water: rivers and streams ○ Lotic ecosystems: flowing water systems that have different habitats created by variations in flow (roll away in the river) Flow webs in lotic systems rely on organic matter clinging to rocks and logs, and soil from adjacent land Insect larvae consume microbes and other organic matter, which creates shredded material that become food for other filter feeders downstream ○ Rivers and streams represent only 0.003% of Earth’s water, but… Streams provide water and deposit fertile soil for agriculture They are pathways for commerce and trade They flood, erode, and sculpt the landscape The US uses water from streams and lakes – on trillion liters per day ○ Stream discharge is volume (m^3 or ft^3) of water passing given point in one second (cross section) * (velocity) = discharge (cross section) = (channel width)(channel depth) ○ Flood recurrence interval: RI = (N + 1)/M N is the number of years of record M is the rank of individual flow within the recorded years Probability of a given flood in any 1 year P = 1/R Statistical probability vs reality Probability: one 25 year flood, on average, once every 25 years Reality: in wapello IA, 200 yr flood occurred in 1993 and 500 year flood occurred in 2008 (15yrs apart) How do humans impact fresh water? ○ Humans alter groundwater and surface water Quantity: Withdrawals Channelization Diversion Use Quality: erosion/runoff Atmospheric deposition Discharges ○ Increased withdrawals from groundwater aquifers  Groundwater is considered a renewable resource, but advances in technology have caused global use of groundwater to expand 10 fold since 1950 Water mining: withdrawals Recharge > 10,000 years (> millions of years considered nonrenewable) Extracted water rarely returns to the original source, so aquifers are not recharged ○ Shrinks rivers and wetlands, and causes ○ Saline intrusion (salt pollution) in freshwater areas close to oceans ○ Subsidence: a sinking or collapse of the ground surface due to water draining from aquifers Permanently reduces ability of aquifer to store and supply water Disruptions to surface water systems ○ Dams, reservoirs, canals, and pipelines, also try to divert water, causing Massive loss of fresh water via evaporation Disruption of fish migration Sediment or eroded materials: are transported and accumulated in different areas In urban developments impervious surfaces (roads, rooftops, parking lots), divert water to storm drains instead of to soil Increasing flows that erode steam banks, elevate peak flows, and scour organisms from streambeds Increase in both flood frequency and magnitude, especially in small drainage basins Increase in runoff, without an increase in precipitation Significant reduction in lag time or flashy discharge Canals and channels impact aquatic habitats and contribute to loss wetlands by preventing seasonal flooding and lowering water table Diverting surface water upstream can diminish available water downstream Upstream dams in Colorado river have diminished water flow especially seen at estuary where it meets Gulf of California Value of Water ○ UN estimates approximately 3.5 mil people die each year due to inadequate water supply or contaminated water, and ⅕ of world’s population suffers from water scarcity ○ Middle eastern countries with inadequate freshwater resources, meet 60% of water needs with desalinated ocean water ○ According to EPA (2022), US Amercans use 82 gallons of water daily ○ Embedded water: accounts for water used to produce goods we consume Can we improve access to fresh water? ○ In some regions of Africa, more than half the population lacks access to safe drinking water. Some people walk 3 hours or more a day to obtain water  ○ Water security: reliable access to safe and affordable water ○ Water stress: when annual water supplies drop below 1700 m^3/person ○ Water scarcity: when annual water supplies drop below 1000 m^3/person ○ More than 2 billion people suffer from water scarcity Where does water go? ○ Globally, agricultural irrigation uses the largest share of water (70%), followed by industry (20%), and public water supplies for residential use (10%) ○ These uses are considered consumptive, since water is removed and not returned to it source ○ 8.7 L day needed for survival ○ 20-50 L for basic human need (WHO) ○ Average american uses 300-378 L day ○ Bottled water industry removes billions of gallons a year of water to be bottled and shipped around the world ○ Americans alone consumed 14.4 billion gallons in 2019 Water shortages: ○ Drought is a prolonged period of low precipitation and high evaporation rates (moisture deficit) that can lead to water shortages Four types: Meteorological: basic moisture deficit Agricultural: deficit affecting crop yields Hydrologic: reservoir levels drop, stream flow decreases Socioeconomic: loss of life, water rationing, wildfires Water conservation and management ○ Not watering landscapes of homes and industries are conservation efforts w big effective impacts ○ Regulating irrigation measures in agricultural areas can be even more effective ○ Another effective conservation method is water recycling which takes residential water, treats it, then uses it for agriculture or industries ○ Desalination: converting seawater to fresh water ○ Distillation: boiling fresh water ○ reverse osmosis: filtering - expensive ($ and energy) ○ Water harvesting allows runoff to be captured from rooftops or at ground level, where pipes and channels direct water to a catchment such as a cistern Chapter 3 InQuizitive: Matter is defined as anything that takes up space, and the amount in a particular object is its mass. We use the term element to describe substances such as gold, calcium, oxygen, and silicon that cannot be broken down into other substances. An atom is the smallest unit of an element that still has all the characteristics of that element. Compound: formed when atoms from two or more types of elements are bonded to each other  Ions: charged atoms Element: atoms of this type always have the same # of protons and therefore the same atomic number Molecule: formed when two or more atoms join together Isotopes: atoms of an element that have different numbers of neutrons than protons Chemical bonds: what holds the atoms in molecules together Oxygen molecules are slightly negative Acids are compounds that yield positively charged hydrogen ions when dissolved in water. Common compounds of this type are found in orange juice and vinegar. Bases are compounds that produce negatively charged hydroxide ions when dissolved in water/ Common compounds of this type are found in bleach. The pH scale is used to express the strength of acid and base solutions. The process of losing electrons is called oxidation, and the process of gaining electrons is called reduction Lecture 3 - 9/10/24 (https://canvas.upenn.edu/courses/1811845/files/137952792?module_item_id=31443458): Average temperature and precipitation regime What is the status of Earth’s biodiversity? ○ Extinction rates: Human impacts have resulted in many extinctions and overall reduction in global biodiversity UN estimates that humans have increased species extinction rate by at least 1000 times since industrialization Some scientists believe that human-driven mass extinction called the “the sixth extinction” is underway ○ Alteration of habitats: Most severe human impact on biodiversity is from physical alteration of habitats, such as agriculture, deforestation, and urbanization Many habitats so fragmented that many species have lost population size and genetic diversity necessary for reproduction and viability ○ Deforestation: clearing of areas of forested land Temperature in water increasing (due to lack of trees) = bad for some species in the water Increasing to the amount of CO2 in the atmosphere Destroying homes for many land-based plants and animals and causes soil erosion In africa more than 90% of harvested wood is used for firewood. In southeast asia, deforestation is often due to conversion for oil palm plantations  ○ Edge effects: occur in places where two or more types of habitats come together, such as a meadow or human development next to a forest, usually resulting in less biodiversity ○ Overexploitation: Humans have also overused of overexploited resources, such as the passenger pigeon Today, we are overexploiting seafood due to modern fishing technologies that result in overharvesting certain economically viable species ○ Introduction of invasive species: When foreign species are introduced to new habitat, natural predators are not often present leading to: Populations increasing without controls Native species being harmed, and reducing biodiversity overall Invasive kudzu vines and english ivy in the US resulted in the smothering and loss of native plants Emerald ash borer, feral pigs, zebra mussels, quagga mussels, cheatgrass, garlic mustard, hemlock wooly adelgid, white-nose syndrome fungus, lionfish, burmese python etc ○ Habitat modification: Effects on water: humans have dammed rivers, changed fish migrations, withdrawn large volumes of water, polluted water systems, and created dead zones Climate change can be seen around the globe, such as the loss of arctic ice (polar bear habitat) and coral bleaching due to ocean acidification and temperature increase Why protect biodiversity? ○ Instrumental value: usefulness of a particular species for human purposes ○ Intrinsic value: value of something in and of itself apart from its usefulness to others ○ Are all species intrinsically valuable, or are only certain ones valuable? ○ Are species valuable only because they have instrumental value (that is, they provide us with food, fiber, entertainment, or some other useful commodity)? ○ What happens if we cannot determine a species’ value? Should we still protect it? ○ What other values, besides economic ones, does a species have? Are these values as important at a species’ value in a monetary sense? What are ecosystem services? ○ Just as we rely upon public services, such as fire protection, we also rely on ecosystem services, such as wetland’s ability to naturally purify water, a necessary resource for our survival Provisioning services: when ecosystems provide goods that humans consume or use Regulating services: where natural processes of ecosystem provide favorable conditions for humans  Supporting services: most essential ecosystem services, bc they provide fundamental conditions on which other ecosystem services depend Cultural services: enhance quality of life, such as recreation and spiritual value ○ Value chains place economic value on ecosystem services by integrating value of a good and market value of things linked to production of that good ○ Replacement costs: estimate cost to replace something with substitute or artificial good Also estimate value from surveys where people provide stated or revealed preferences regarding what they would pay to maintain healthy ecosystems ○ Criticisms of ecosystem service approach Economic values are not always easily quantifiable or encompassing “Expendable species,” that do not have (apparent) instrumental value, may be identified as a justifiable loss Once artificial substitutes are discovered to replace natural services, the ecosystem service will no longer be valued What can be done to reduce biodiversity loss? ○ Manage populations of individual species: Requires restoration and maintenance of healthy populations Affected by several factors Population viability Availability and quality of habitat Size of population disease/predators Umbrella species Species whose protection protects other species that require similar habitat ○ Manage habitats Preserves and protected areas Affected by several factors Size: larger preserves support more species Connectivity: migration corridors, distance from other preserves Buffers Protect from human influence/disturbance What are protected areas? ○ Federal government creates areas where ecosystems are protected: Parks Monuments Recreation areas Wildlife refuges Forests wilderness areas  ○ Managed and maintained by National park service Us fish and wildlife service Us forest service Bureau of land management ○ National monuments and recreation areas Establishing a national park requires congressional approval Congress passed antiquities act (1906), empowering president to set aside federal lands as national monuments without congressional approval Some national parks (grand canyon, teton) began as national monuments National recreation areas: conserve and provide recreation often around reservoirs created by large dams ○ National forests: lands are owned and managed by the US forest service (USFS) for multiple purposes including timber harvests, recreation, and fish and wildlife conservation Bureau of land management lands ○ Originally established to manage grazing and mining on federal lands ○ Since 1970s, blm mandates requirements for multiple uses besides resource extraction ○ Now required to conduct long-term planning with public involvement ○ Blm collects fees and sets conditions for > 18,000 grazing permits > 300 coal-mining operations ~ 63,000 oil and gas wells ○ Companies using public lands pay a percentage of the profit they make to the government What are the limitations of protected areas, and are there alternatives? ○ When protection stops at a boundary, preserving species can fail if area’s size does not meet species needs ○ Ecological island effect: when protected habitat is isolated amid wider unprotected areas Increased vulnerability to disease Increased likelihood of inbreeding One solution is creating wildlife corridors: protected strips of land that enable migration from one habitat to another ○ Continued human use ○ Many protected areas are designed for multiple uses ○ Most global protected areas still experience poaching as well as illegal logging and mining operations ○ Enforcement is challenging bc these areas are difficult to access, it provokes conflicts, and employment training is expensive Laws to protect biodiversity:  ○ Lacey act (1900): prohibits trade in wildlife, fish, or plants taken illegally, establishing US fish and wildlife service to enforce it ○ US and Canada ratified Migratory Bird Treaty Act (1918) protecting more than 800 types of birds ○ Marine mammal protection act (1972): protects whales, dolphins, seals, and manatees ○ Endangered species act (esa 1973): protects both endangered plants and animals from hunting and trapping ○ International laws/policy to protect biodiversity Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES): international agreement banning hunting, capturing, and selling of endangered and threatened species ○ Convention on Biological Diversity (1992) international agreement committing countries to pass laws to expand protected areas, restore degraded ecosystems, and ensure sustainable and equitable human use of ecosystem services What can be done to reduce biodiversity loss? ○ Sustainable forest management strategy that manages forests not only for harvest but also for maintaining biodiversity important practices include leaving patches of living trees to reseed along with patches of dead trees known as “snags” as bird habitat and prohibiting logging on steep slopes to prevent erosion ○ Grazing and Grassland Management grasses grow from base of blade and have extensive root systems, can withstand periodic and sustainable grazing grazing animals also spread seeds in grasslands and help fertilize soil modern livestock alter balance and damage grasslands if not carefully managed by rotating confined herds from area to area ○ Agriculture and Protection of Biodiversity some types of crops such as nuts and fruits can serve as habitat for specific species hedgerows of native plants planted around cultivated fields can provide a network of habitat corridors across rural landscapes, and protect against wind erosion ○ Urbanization and Land-Use Planning how we plan where we live involves land-use planning in United States and is done at the state and local levels zoning ordinances are regulations that mandate types of development, land uses, and human activities that are allowed (and disallowed) in particular places strategic zoning often attempts to manage growth while preventing and limiting suburban sprawl What can be done to fix damage that has already occurred? ○ species can be reintroduced to an area where they once lived  ○ captive breeding programs have difficulties: Expensive tends to have a low probability of success captive population is usually small with lack of genetic diversity that decreases fitness of offspring generations of confined species may become less fit for the wild ○ ecological restoration is process of assisting recovery of an entire ecosystem In 1960s, US Army Corps of Engineers built canals, levees, tide gates, and pumping stations to change flow of Everglades to benefit farming and urban development - destroying vast system of lakes, streams, and wetlands Comprehensive Everglades Restoration Plan (1996) by US Army Corps of Engineers and South Florida Water Management District restored 70,000 acres of wetlands federal funding, nongovernmental groups, and legal processes that levy fines on polluters through Natural Resource Damage Assessment provide revenue for restoration projects Lecture 2 - 9/5/24 (https://canvas.upenn.edu/courses/1811845/files/137763178?module_item_id=31418105): Matter: anything that takes up space, has mass, and usually can exist as a solid liquid, or gas ○ Amount of matter in a particular object is its mass Law of conservation of mass: Matter cannot be created or destroyed ○ Mass of constituent parts in a chemical reaction remains unchanged even as atoms involved in reaction are rearranged ○ EX: when wood (cellulose) reacts with oxygen in a fire, it produces an equal number of atoms in different forms (carbon dioxide gas, water vapor, and charcoal ash) Phase change: a change of matter from one state (solid, liquid, or gas) to another without changing its chemical composition ○ Gasses can undergo pressure changes due to the rapidly bouncing and colliding molecules’ continuous physical force against a container EX: pumping air into a bike Molecules can also break apart and combine into new molecular arrangements through chemical reactions ○ Combustion of fuels and building larger molecules result in oxidation-reduction (redox) reactions  ○ Polymerization reactions, small molecules (monomers) join to create new and larger chain-like structures (polymers). Depolymerization reactions break polymers into smaller monomers. Energy: capacity to do work Work: act of applying force to an object over some distance ○ Energy exists in universe in form of heat, light, chemical bonds, and motion What happens to energy when we have used it? ○ Energy, like matter, is a constant in the universe – First Law of Thermodynamics is that energy cannot be created or destroyed ○ Second Law of Thermodynamics: with each transfer of energy, some energy is degraded and dissipates in form of heat, resulting in tendency of any isolated system’s entropy (a measure of disorder) to increase Energy conversions are never 100% efficient due to entropy How does energy affect life? ○ Ecologists categorize living things by the tropic levels, which is their place in the food chain ○ Plants, algae, and some bacteria transform sunlight into chemical energy through photosynthesis and are called primary producers ○ Primary consumers are organisms that directly consume these producers for their energy ○ Only 10% of energy from consumed organic matter transfers to the next trophic level, resulting in significant energy loss Organism < population < community < biosphere < ecosystem Ecology: study of relations of living things to one another and to their non-living surrounds Biodiversity: variety of living things on Earth Adaptive radiation: ancestral species may diversify over many generations, producing variety of new species adapted to specific sets of conditions, or niches, of an ecosystem Genes: basic units of inheritance between parent(s) and offspring ○ Sections of molecules called DNA (deoxyribonucleic acid) that direct what cells make and how they function ○ Organisms inherit different forms of a gene (alleles) from each parent leading to variation  ○ Combination of genes received produces traits through a complex process of gene expression Mutation, selection, and extinction ○ Genotype: genetic makeup of an individual ○ Phenotype: individual’s expressed traits or characteristics ○ Gene mutations: changes to DNA that may alter a trait, may be harmful, neutral, or beneficial ○ Extinct: if traits of an entire species make it unable to adapt to its environment, which is loss of that species from Earth  ○ Five misconceptions about evolution: ○ Evolution = progress Evolution is not goal-oriented, purposeful, or intentional ○ Individuals can evolve Evolution changes the genetic makeup of populations over time ○ In evolution, only the fittest survive “Survival of the fittest” is the ability to pass on one’s genes to the next generation in greater proportion to other individuals. Those with certain traits will survive and produce more offspring than others ○ Evolution takes a long time, so humans have no effect Humans change environmental conditions, changing which traits are favored What causes population traits to change? ○ Speciation: occurs when subsets of a population diverge genetically and can no longer produce fertile offspring ○ Reproductive isolation: can be due to geographic, morphological, temporal, or structural barriers between separated populations ○ With small populations, inbreeding between closely related individuals often occurs Less adaptive traits continue to get transferred, resulting in a weaker population ○ If two previously separated populations mix and interbreed, gene flow (transfer of genetic material from one population to another), causes genetic differences between individuals to decrease, while genetic diversity increases ○ Genetic drift: chance-based change in trait frequency, and affects allele frequencies in small populations 86% of land species and 91% of ocean species yet to be discovered What shapes biodiversity? ○ Community biodiversity: refers to number of species, their relative abundance, and their arrangement in space in a particular location ○ Landscape biodiversity: refers to variety and abundance of species from place to place ○ Patterns driven by changes in environment conditions, e.g.: Net primary production Past disturbance Habitat gradients Ecosystem complexity ○ Species richness: the total number of species in a given area ○ Species evenness: the relative abundance (or dominance) of species in a given area  Quantifying biodiversity ○ ○ Rank abundance curve (Whittaker plot) Visually depicts both richness (max x-axis) and evenness (slope) Steep gradient indicates low evenness as the high-ranking species have much higher abundances than the low-ranking species Shallow gradient indicates high evenness as the abundances of different species are similar ○ Snipe island brook is more even How do communities of organisms interact? ○ Competition: occurs when one individual reduces the availability of a resources, such as food, water, or potential mates, for others Competition is a negative-negative interactions (negativity for both species) May be: Exploitative: occurs indirectly by using resource and allowing less for competitor Interference: direct fighting for a resource Different species may coexist if they each exploit a different ecological niche, or a particular role in a community, which is called resource partitioning, and this reduces interspecific competition  ○ Predation: where one organism (predator) feeds on another (prey) ○ Parasitism: type of predator-prey relationship where one organism (parasite) lives off another organism (host) without usually killing it ○ Herbivory: another type of predation. Moose, as herbivores, eat balsam fir trees ○ Coevolution: occurs when two or more species evolve together, with adaption of one species causing second species to adapt too If second species further adapts, then first species may also need to adapt, leading to an “evolutionary arms race” for survival Results may be beneficial or detrimental to both species ○ Symbiotic relationships: occur when two organisms are closely associated with each other in a long-term relationship, one type being parasitic relationships ○ Commensalism: when one organism benefits while other experiences no effect ○ Mutualism: benefits both organisms involved in a win-win situation What controls population size? ○ In population dynamics, additions occur when individuals reproduce (births) or by immigration to different areas, and losses occurs when individuals die or emigrate ○ If birth and immigration numbers equal death and emigration numbers, then a population will be in equilibrium ○ If births and immigration numbers outpace deaths and emigration, the population will rise, with the reverse pattern decreasing the population Population growth and responses to limits ○ exponential growth (geometric growth): when conditions for growth are ideal, populations can increase very quickly over time ○ carrying capacity: maximum number of individuals of a species that habitat can sustainably support If a population grows beyond carrying capacity, all resources needed to survive may be used, resulting in a population crash ○ As population increases within a specific area, density-dependent factors may cause stress and make populations more susceptible to environmental harms as available resources for each individual decrease Death rates may increase, or birth rates may decrease ○  What can cause loss of biodiversity? ○ Extinction: permanent loss of species Can occur steadily over time or through rapid mass extinctions events Earth has experienced five mass extinction events, with the largest about 252 million years ago following massive volcanic eruptions. More than 90% of terrestrial and marines species were lost Some species can become functionally extinct where their roles in ecosystems are greatly reduced before they become extinct Identifying areas and species vital to biodiversity ○ Biodiversity hotspots: places where large numbers of species are particularly vulnerable to extinction These regions have high number of endemic species, specialized to exist under particular environmental conditions, restricting their location ○ Keystone species: exhibit particularly strong influence over abundances and diversity of other organisms in their ecosystem Lecture 1 - 9/3/24 (https://canvas.upenn.edu/courses/1811845/modules/items/31390364): What is the environment? ○ A collection of systems encompassing all of the physical, chemical, and biological factors and processes that determine the growth and survival of an organism or community of organisms What is sustainability? ○ Meeting the needs of the present w/o compromising the ability of future generations to meet their own needs (Our Common Future, 1987) ○ Not borrowing from future generations ○ ○ The three Es – environment, economy, and equity  ○ Problems with Sustainability ○ Non-Renewable ○ becoming increasingly difficult to determine activities that are truly/strictly sustainable Sustainable Development ○ Two themes: Protecting the planet Investing in the future we want ○ Success depends on: Improved ability to monitor and forecast long-term trends Ecosystem-social system connections Thresholds of change Incentives for sustainable behavior Integration of learning and action Sustainability science: Aims to understand the interactions between between environmental systems and social systems Environmental science: field of study that applies the scientific method to examine interactions between natural and human systems (not all are environmentalists) Environmentalism: social movement that seeks to protect the environment through lobbying, activism, and education System: any portion of the universe that can be isolated from the rest for the purpose of observing and measuring changes ○ Made up of interaction components that produce patterns of behavior over time, like a household  ○ Ecosystem: the combination of a community of organisms and its physical and chemical environment with which it interacts, functioning as an integrated unit ○ Includes both biotic and abiotic factors ○ Connected by the flow of energy and matter ○ Living and nonliving A healthy ecosystem can usually withstand natural and human-caused events - resistance Sustainable ecosystems display ecological resilience - how well systems recover after disruption 3 Es: Environment, economy, equity Environmental justice (EJ) raises awareness that poor and marginalized communities receive more environmental harms and fewer environmental benefits, and seeks to right these injustices ○ A global concern Science  ○ Pseudoscience: other claims may not intend to deceive but have not used the scientific method ○ Old farmer’s almanac CRAAP ○ C - current ○ R - relevant ○ A - authoritative (who’s the author?) ○ A - accurate ○ P- purpose Characteristics of good science: ○ Example: Global warming - average temperature of Earth is increasing due to build up of greenhouse gasses in the atmosphere Tentative: estimates of how much temperature is increasing can change Empirical: measurements of increasing global temperatures Predictable: if carbon dioxide increases by X, temperature will increase by Y Natural Cause: radiative properties of gasses Characteristics of bad science: ○ Bad statistics or visualization ○ An attack on the scientist, not the science ○ People who argue from authority ○ Confusion over cause and effect ○ Use of value instead of critical judgments  Trade-offs and incentives ○ Trade-offs: when considering the pros and cons, or benefits and costs, of alternative courses of action ○ Public agencies and businesses may use communication strategies that intend to raise our cost-and-benefit awareness, which may alter our decisions based on our cost-benefit analysis ○ Other strategies may include positive or negative incentives meant to influence our choices Anthropocene: new, current epoch of Earth history recognized by many scientists, which is marked by conspicuous human effects on the planet. ○ Humans’ effect on the environment