BIOL 1010 notes weeks 2-4
BIOL 1010 notes weeks 2-4 BIOL 1010
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This 13 page Class Notes was uploaded by Luke Giesler on Thursday September 15, 2016. The Class Notes belongs to BIOL 1010 at Bowling Green State University taught by Kevin Neves in Fall 2016. Since its upload, it has received 38 views. For similar materials see Environment of Life in Science at Bowling Green State University.
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Date Created: 09/15/16
Science literacy: what's it about Main concept depletion of stratospheric ozone caused by synthetic chemicals allows dangerous solar radiation to reach the earth's surface. The scientific process allows us to understand this relationship better. Q why was stratospheric ozone disappearing above the south pole?? What is ozone? A molecule of 3 oxygen atoms o3 A natural component of the stratosphere that shields the earth from UV rays. Ozone found in the troposphere is harmful to living things The atmosphere Ozone is a key element of the atmosphere, the blanket of gases surrounding our planet. Composed of several layers that differ in gasses. Use the scientific method to answer Science is a body of facts and explanations And It’s worth noting that facts may change as more data is collected. Limited to asking questions about the natural world: physical phenomena that can objectively be studied Science is not, subjective, ethical, or spiritual questions. Observation Information gathered with our senses or equipment that extends our senses (microscope, thermometer) Inference Explanation of what might have caused the phenomena (Basically a guess) (Q) What depletes ozone? key culprit: Chlorofluorocarbons (CFCs) Humanmade molecules: Coolants for refrigeration Styrofoam Hypothesis A tentative explanation Good hypothesis are testable and falsifiable. Science proceeds by accepting or rejecting the hyp Hypothesis can never be proven “correct.” Hypothesis CFCs are breaking down the ozone Prediction Polar clouds and sunlight were causing CI to react with O3 Then many CLO How to: Test a Hypothesis Observational studies Data collected in the real world No manipulation Can only show correlations Experimental studies Data collected by manipulating variables Uses test groups and control groups Can show cause and effects Correlation When two things occur together but one does not necessarily affect the other. Cause and Effect when two things occur together but one directly occurs in response to, or as a result of, the other Types of variables Independent variables The factor being manipulated Dependant variables The response of an organism or the characteristic that is measured Control variables All other things should be held constant during the experiment Day 2 Types of groups 1.) Test groups Groups that is exposed to different levels of the independent variable 2.) Control groups Provides the standard of comparison for the test groups The “baseline” 3.) Replication Repetition of treatments (including controls) Conducting the experiment many times. How do I know if my groups are really different? 1.) Statistics Determine if differences exist between test and control groups Assign a level of certainty to our conclusions A probability value(or P value) is used to determine significance between groups: Typically 5% or less (i.e.,P<0.05), i.e., we are 95% sure our conclusions are correct Is ozone depletion (and increased exposure to UV rays) causing skin cancer. Theory A widely accepted explanation for a natural phenomenon that has been extensively and rigorously thought out and tested. Montreal Protocol 1987 Administered by the U.N. A plan developed to phase out CFCs By 2009, every country had signed the agreement governments developed their own policies for reduction of CFCs Policies= Translating values into action The U.S. banned CFCs in certain products in the 1970s In the early 1990s, the U.S. started phasing out CFCs entirely Industry, public, and government sectors cooperated to find solutions to this problem. The Precautionary Principle Though you are not 100% sure of what is causing a problem, there is a big risk to “doing nothing.” Taking action E.g., Montreal Protocol 1987 Susan Solomon's studies published Adaptive Management A plan that allows you to alter strategies as new information comes in or the situation changes (e.g., the original Montreal protocol target list was not comprehensive.) Present and Future ozone levels 2011, Largest ozone “hole” ever recorded above the arctic 2050, MidLatitude areas back to pre 1980 ozone levels 2075 polar regions back to pre 1980 ozone levels Chap 3 Information literacy and toxicology Toxic Bottles Discussion question are you ever concerned about the chemicals that are used to produce the products that are used to produce the products you use every day? Why or why not? Washing machines making you sterile? AllNatural Toothpaste Cookware poisoning you? Just google it! ● Toxins are chemicals that cause direct damage upon exposure Toxins fall into two categories, natural and synthetic. ● According to the EPA: More than 80,00 chemicals are used in the US 1,0002,000 new chemicals enter the market each year ● Natural Toxins are not always safe. Arsenic, a basic element, can cause cancer and nervous system damage in humans. ● Synthetic Toxins are a problem because many are persistent chemicals they don’t readily degrade over time. Low persistence chemicals break down quickly High persistence chemicals linger into the environment longer How soluble is the substance? ● Water and other liquids: May be safer for humans excrete in the urine Still potentially toxic at high doses or continuous low dose High impact on aquatic organisms easy uptake ● Fat soluble Cross cell membrane in humans and hard to eliminate Some break down by liver Storage and accumulation in fatty tissue ● Fat soluble substances can build up Bioaccumulation occurs in Individuals levels increase over time. Biomagnification occurs up the food chain individuals higher on the food chain will accumulate more toxins than those lower on the food chain. ● Regulation of toxins begins with risk assessment a careful weighing of the risks and benefits associated with any given chemical. ● Federal agencies (FDA, EPA) are mandated with protecting us from harmful chemicals. They can heavily regulate or ban those deemed dangerous. ● In 2008, the National Toxicology Program (NTP) analyzed studies about Bisphenol A, or BPA ● NTP stated it had some concerns about the effects of BPA exposure on brain behavior ● Canada and the European Union had recently banned BPA on the use of baby bottles and baby food cans ● Most NTP panelists felt the data were too uncertain to warrant a ban but they applied the precautionary principle saying it would ● Toxicologist create a dose response curve to track the effects of a dose of a chemical, such as BPA. EXAM SEPT 27TH!!!!!! In Vitro in glass studies, petri dish Epidemiological studies subjects being diagnosed with disease ● Toxicologist use this curve to calculate the LD50 (lethal dose 50%), the dose that would kill 50% of the population. ● The lower the LD50, the more toxic the substance. In this example, Substance A is the more toxic substance. ● BPA is an endocrine disruptor: It mimics a hormone or prevents a hormone from having an effect. ● Endocrine disruptors have different effects at low and high doses, so doseresponse curves and LD50s are trickier to calculateand a “safe dose” is harder to determine. ● As scientists debated the safety of BPA, and regulatory agencies struggled, people were left to decide whether they should purge BPA from their lives. ● We can use critical thinking skills to analyze reports on potential toxins and help us determine what steps we should take to be safe. ● To make decisions, we need to know whether a chemical has the potential to harm us and how great that harm might be. First we must evaluate the information. Evaluate the evidence Is the claim from actual scientific studies? How relevant are the studies? Did the researchers look at human populations? Be openminded. Identify your own biases or preconceived notions and follow the evidence where it takes you. Watch out for biases: Is the author promoting a specific position? Are they financially tied to a specific conclusion? Are they trying to support a predetermined conclusion? ● There are rarely easy answers and science is never as straightforward as we would like it to be. ● We are constantly uncovering new information and as our understanding grows, existing information often becomes obsolete. Science is incremental: Each study is a piece of the puzzle. Week 4 Notes. Chap 15 Toilet to Tap Freshwater is water that has few dissolved ions, such as salts. Wastewater is used and contaminated water released after use by households, Industry, or agriculture. Surface water is any body of water that is found above ground, such as oceans, rivers, and lakes. Water provides many ecosystem services to animals and plants. Humans are 75 percent water but we require freshwater. Facing water shortages, a county in California tried an unusual approach: treating sewage water to create a source of drinking water. *Sewage water shit water Although 75% of Earth’s surface is covered by water, only 1/100 percent is usable by humans. Nearly 90% of the freshwater on the planet is trapped in ice caps and glaciers. Wherever is is, water moves through a water cycle: cycling between gaseous and liquid states. This process sends 17,00 trillion gallons of water vapor into the atmosphere every year. Once aloft, that water condenses (condensation) and may fall back to Earth as precipitation (rain, snow, sleet, etc.) Almost all precipitation falls in the oceans. But a tiny amount falls on land, which is what humans can access. Ocean water is too salty for humans to consume, and can be toxic in large doses. Q?? Most of the water that humans use comes from? Lakes Rivers Lakes and rivers Groundwater reserves People don’t always live near abundant amounts of water WHO (World Health Organization) estimates that 1 in 3 people more than 2 billion lacks sufficient access to clean water. As populations increase, so will water scarcity: the United nations estimates 2 out of 3 people will face water shortages by 2025 California faces several water challenges: Northern California gets freshwater from melting sierra Mountain snowpack which may decrease with climate change Twothirds of the state's water is in northern California, but twothirds of the population is in the south. Shipping water south is costly and earthquakes could cut off the water supply. Desalination of nearby ocean water is expensive and uses a large amount of energy Many people not just in California rely on aquifers, underground regions of rock or soil permeated with water. California discovered saltwater was infiltrating some aquifers putting that water supply in jeopardy Increasing population also led to increase in wastewater: 100 million gallons/day of partially treated sewage water was flooding the Santa Ana River. After much community discussion, the groundwater replenishment System went online in 2008; now 70 million gallons of recycled water are pumped into wells daily. Solving water shortages is not easy Some communities dam up rivers to create reservoirs but these lose water every day through evaporation. Arcata, California, converted a landfill to wetlands and sends sewage water to be consumed by organisms in order to purify it. The Orange County system was costly $487 million. A less expensive approach is water conservation. Agriculture uses the most water and creates the most waste. Water saving irrigation methods limit loss to evaporation and runoff, reducing water usage. Many industrial processes now reuse water instead of discharging it into the environment. Small changes in the household such as low flow toilets, can also save a lot of water Buying less stuff and using less energy also saves water because much water is used to produce both. Into the Gulf The making of a dead zone, far upstream Water pollution is anything that has been added to water that might degrade water quality Clarity Color Content Stormwater runoff is water from precipitation that flows over the land surface and does not seep into soil. These pollutants include: Industrial chemicals Raw Sewage Garbage Oil Fertilizers Pesticides Metals, such as mercury Sediment Heat Clean Water Act (CWA) of 1972 mandates that all waters must be “fishable and swimmable.” CWA regulates industrial and municipal point source pollution by setting allowable levels of a pollutant in the environment. Classes of pollution The source of Point source pollution can clearly be identified Nonpoint Source (NPS) Pollution cannot be attributed to a single source; therefore they are difficult to regulate NPS can include: Natural and synthetic chemicals Often includes nutrients ● Excess nutrients can lead to Eutrophication or excess plant growth ● Too many plants creates a lot of shade, which blocks the sunlight ● Plants begin to die, and the bacteria that feed on dead plants, consume oxygen leading to hypoxia or low oxygen ● Hypoxia will occur when dissolved oxygen becomes very low, to the point where it cannot support many aquatic organisms ● A “dead zone” forms when all aquatic life dies. ● Increases of farm runoff leads to decreased infiltration, which cuts down on the overall quality of groundwater ● Increased runoff results from the concept of river channelization. ● Many of the wetlands in the world have been drained for the development of agriculture ● Wetlands filter and store water naturally. A loss of the wetlands allows more water to enter the rivers. ● For the Mississippi watershed increased runoff and river flow means more pollution finding its way into the gulf ● The pollution includes fertilizers from farmlands ● 1.5 million metric tons of phosphorus and nitrogen enter the gulf from the Mississippi. Why so much nitrogen in the rivers?? There's a lot of soybeans and corn being grown than oats and alfalfa The use of synthetic fertilizers increases Large agriculture fields with drainage systems (tile lines) they bring the used water away from the crops. Alternative Farming techniques can reduce sediment erosion and nutrient loss Conventional versus Controlled drainage Organic farming practices Planting cover crops in the fall/winter Agriculture best management practices include: Protecting riparian areas by creating vegetated buffer zones. Testing soil to determine fertilizer needs. Tilting fertilizer directly into the soil Planting rows of trees as windbreaks Watershed management is an approach to reducing nonpoint source pollution such as runoff from farms and roads. Watershed management goals: Restore and conserve habitat Restore water quality Replenish and protect marine resources Enhance community resilience In urban and suburban areas changes can also make a difference. Apply less fertilizers to lawns. Plant a native plants Plant a rain garden? Capture rain with a rain barrel Use porous concrete or pavers.
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