Environmental Science Midterm Review PDF

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Environmental Science MIDTERM REVIEW #1 Chapter 2 

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Science: a process for producing knowledge methodically and logically.  Derived from “scire” (to know) in Latin.  It depends on making precise observations of natural phenomena.  The cumulative body of knowledge produced by many scientists. MIDDLE AGES: ultimate sources of knowledge about how crops grow, how diseases spread, or how the stars move, were religious authorities or cultural traditions. SCIENTIFIC THINKING: searches for “ TESTABLE EVIDENCE” BASIC PRINCIPLES OF SCIENCE: Empiricism  We can learn about the world through careful observation of empirical (real, observable) phenomena; we can expect to understand the fundamental processes and natural laws by observation. Uniformitarianism  Basic Patterns and processes are uniform across time and space: the forces at work today are the same as those that shaped the world in the past and they will continue to do so in the future. Parsimony  When two plausible explanations are equally reasonable, the simpler ( more parsimonious) one is preferable. This rule is also known as [OCKHAM’S RAZOR] after the English philosopher who proposed it. Uncertainty  Knowledgeable changes as new evidence appears, and explanations (theories) change with new evidence. Theories based on current evidence should be tested on additional evidence with the understanding that new data may disprove the best theories. Repeatability  Tests and experiments should be repeatable; if the same results cannot be reproduced then the conclusions are probably incorrect. Proof is elusive  We rarely expect science to provide absolute proof that a theory is correct, because new evidence may always undermine our current understanding. Testable Questions  To find out whether a theory is correct, it must be tested; we formulate testable statements (Hypotheses) to test theories. Explanations are considered only provisionally true because there is always a possibility that some additional evidence may appear to disprove them: Scientists are SKEPTIC. Scientists aim to be methodical and unbiased. They demand (Reproducibility) because they are cautious about accepting conclusions. Replication: Repeating studies or tests Accuracy: Correctness of measurements. Precision: repeatability of results and level of details. Throwing darts at the board.

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Significant Figure: a level of detail you actually knew. Deductive Reasoning: Logical reasoning from general to specific. Inductive Reasoning: Reasoning from many observations to produce a general rule. We often rely on inductive reasoning because we have few immutable laws. Barbara McClintock’s Corn experiment:  Genes in corn can move and recombine spontaneously.  Her intuitive understanding led to a theory that took other investigators years to accept. SCIENTIFIC METHOD (FLASHLIGHT) Observe  Observe that your flashlight doesn’t light; also that there are three main components of the lightening system (batteries/bulb/switch) Hypothesis  The flashlight doesn’t work because the batteries are dead. Test/Predict  “I will replace the batteries and the light should then turn on”. Data  After you changed the batteries, did the light turn on? Interpret  If the light works now, then your hypothesis was right, if not, then you should formulate a new hypothesis, perhaps that the bulb was faulty and develop a new test for that hypothesis. Natural Experiment: a study of events that have already happened.  [Study of colds and sleep deprivation-an example of an observational experimentyou observe natural events and interpret a causal relationship between the variable] Manipulative experiments  B4Warmed experiment: some conditions are deliberately altered and all other variables are held constant. Controlled Study  by comparing a treatment (Exposed) group and a control (unexposed) group. Risk of experimenter bias  avoid bias by using a blind experiment [researchers don’t know which group is treated until after the data have been analyzed] Double-Blind Experiment:  neither the subject (who receive a drug or a placebo) nor the researcher knows who is in the treatment group and who is in the control group. Dependent Variable  Response variable, affected by the independent variable. Independent Variable:  rarely really independent, affected by the same environmental conditions as the dependent variable. (A.K.A- explanatory variable) Model

a simple representation of something. [ Models can be numeric or physical models]. Often called simulation models because they simulate a complex system. System  a network of interdependent components and processes that together have properties beyond those of individual parts. Feedbacks  self-regulating mechanisms in which the results of a process affect the process itself. Homeostasis  The ability to maintain stability and resilience (the ability to recover from disturbance) are important characteristics of systems. Ecosystem  stands for a complex assemblage of animals, plants and their environment, through which materials and energy move. Simple System  consists of two variables (a.k.a compartments) which store resources such as energy, matter, or water and flows or the pathways by which those resources move from one state variable to another. Open system  receive inputs from their surroundings and produce outputs that leave the system. Almost all NATURAL SYSTEMS are open. Closed system  exchanges no matter or energy with its surroundings but these are rare. Pseudo-closed systems those  that exchange only a little energy but no matter with their surroundings. Throughput  Used to describe the energy and matter that flow into, through and out of a system.  Larger throughput might expand the size of the state variable  IN grassland, inputs of energy (sunlight) and matter (Carbon Dioxide and Water) are stored in biomass.  Grassland is an open system. 

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Positive Feedback  Self- perpetuating process.  Grass plant grows new leaves, more leaves=more energy.  Warm summers=melt ice in the Arctic=newly exposed waters absorb heat= more melting=more absorption.

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Negative feedback  The process that suppresses change.  Too many leaves than can be supported by the available soil moisture  With insufficient moisture, the plant begins to die back.  Warming atmosphere= evaporate more water, producing clouds= clouds block solar heat=reduced evaporation=slow warming process.

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Your body is a system of negative feedback  You exercise, you become hot, and your skin sweats, which cools your body.

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Homeostasis  The tendency to remain more or less stable and unchanging.  Equilibrium is another term for stability in a system.

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Disturbances  Events that can destabilize or change the system might also be normal for the system.  Grasslands experience occasional fires that stimulate grass growth (by clearing accumulated litter and recycling nutrients) but destroys trees that might be encroaching on the grassland.  Often part of natural systems.  Consider this “Dynamic Equilibrium” or a tendency for a system to change and then return to normal.

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Resilience  An ability to recover from disturbance.  Species-rich plots mau show more resilience than species-poor plots  Sometimes severe disturbance can lead to a state shift

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State Shift  Conditions do not return to “normal”.

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Emergent Properties  Characteristics of the system that are greater than the sum of its parts.

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An ecosystem can have emergent properties such as spatial structure, complexity, and diversity that individual components of the system could not have. Your ability to think, share ideas with people around you, sing and dance are properties that are emergent because you function as a system.

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Science is an incremental process in which many people gradually reach a consensus. Critical thinking helps us evaluate scientific evidence. Many people misunderstand the role of uncertainty in science. Scientific Consensus  A general agreement among informed scholars.

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Paradigm Shifts  According to Thomas Kuhn: paradigm shifts occur when a majority of scientists accept that the old explanation no longer explains new observation very well.  Shift is often contentious and political because whole careers and worldviews, based on one sort of research and explanation can be undermined by a new model.

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Quantum mechanics and Einstein’s theory of relativity overturned classical physics in only about 30 years.

Conclusion:  Science is a process for producing knowledge methodically and logically.  Hypotheses and theories are basic tools of science. It is a testable question.  The theory is a well-tested explanation that explains observations and that is accepted by the scientific community.  Probability is also a key idea: chance is involved in many events and circumstances can influence probabilities such as your chances of getting an A in this class.  Models and systems are central ideas.  The system is a network of interdependent components and process. Chapter 3 

Atoms: the smallest particles that exhibit the characteristics of an elements.  Made up of positively charged protons and negatively charged electrons and electrically neural neurons.

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Water molecules  Polar: slight positive charge  The only inorganic substance that exists as a liquid  Cohesive: hold together tenaciously and create high surface tension. Subject to capillary actions  High heat of vaporization.  High specific heat.

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Acids (pH below 7)  Substances that readily give up hydrogen ions in water. (Hydrochloric acid)

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Bases (pH above 7)  Substances that readily bond with Hydrogen ions A.KA alkaline substances. (Sodium Hydroxide)

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DNA  Deoxyribonucleic acid  Adenine, guanine, cytosine, thymine

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From living organisms to ecosystems, life can be understood in terms of the movement of matter and energy To understand how matter and energy cycle through living things ,we must understand how atoms bond together to form compounds Carbon based (organic) compounds are the foundation of organisms Matter exists in solid, liquid, gas and plasma. Conservation of matter: material is recycled over and over again.

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Population

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Consists of all the members of a species living in a given area at the same time. Biological community: all the populations living and interacting ina particular area.

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Ecosystem  Composed of a biological community and its physical environment

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Abiotic factors  Non living components  Climate, water, minerals, and sunlight  Biotic: living

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Microbiome  Bacteria, fungi, protozoans, and other organisms

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Food chain  A linked feeding system- form a food web

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Trophic Level  An organisms feeding status in an ecosystem

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1. Producers ( photosynthetic plants, algae bacteria) 2. Primary Consumers (herbivores) 3. Secondary Consumers (carnivore 4. Tertiary consumers (top carnivore) Hydrologic Cycle  Path of water through the environment.  Living organisms emit the moisture they have consumed through respiration and perspiration. The moisture reenters the atmosphere or enters lakes and streams from which it ultimately returns to the ocean again.

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Carbon Cycle  Begins with the intake of carbon dioxide by photosynthetic organisms.  Photosynthesis produces plant cells from carbon in the air.  Carbon Dioxide is eventually released during respiration. Closing the cycle.  Biological accumulation and release of carbon is a major factor.

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Nitrogen  Nitrogen is abundant in our environment. It makes up 78% of our atmosphere.  Plants cant use Nitrogen directly, they have to rely on bacteria living in the soil.  “Nitrogen fixing” bacteria breaks Nitrogen which then combines with Hydrogen to create Ammonia - NH3.

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Phosphorus cycle  Phosphorus travels gradually downstream as it is leached from rocks and minerals.

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Repeatedly through the food web as inorganic phosphorus taken up by plants, incorporated into organic molecules and passes on to consumer.

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Photosynthesis  Converts radiant energy into high quality chemical energy in the bonds that hold together organic molecules.

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First law of thermodynamics  Energy is conserved, it is neither created nor destroyed under normal conditions.

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Second law of thermodynamics  With each successive energy transfer or transformation in a system less energy is available to do work. Energy is degraded to lower quality forms or it dissipates and is lost.

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Entropy  Disorder

Chapter 5  Biomes  Areas sharing similar climate, topographic and soil condition, and thus the same basic types of biological communities. 

Temperature  controlled biomes often occur in latitudinal bands

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Cloud forests  High mountains where fog and mist keep vegetation continually wet.

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Tropical Rainforest  Occur where rainfall exceeds 200cm per year and temperatures are warm to hot year round.  Occur where rainfall is abundant  Soil tends to be old, thin, acidic, and nutrient-poor.

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Tropical Seasonal Forest  Many tropical regions are characterized by wet and dry seasons with hot temperatures year round.  Drought-tolerant forests that look brown and dormant in the dry season but burst into vivid green during the rainy months.  Soils of dry forests often have higher nutrient levels and are more agriculturally productive than those of a rainforest.

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Deserts

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Occur where precipitation is rare and unpredictable Can appear barren and biologically impoverished but while their vegetation is sparse, it can be surprisingly diverse.

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Chaparral  Spanish for “thicket”  High number of unique species, human homes built in chaparral harm endangered wildlife and burn periodically.  Inhabited by drought-tolerant animals (jackrabbits, kangaroo, rats, mule deer, chipmunks, lizards)

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Deciduous (losing leaves seasonally)  Deciduous forests:  “ rainfall is plentiful”  Southern live oaks.  Can regrow quickly because they occupy, moist moderate climates.  Greatest threat is Siberia (has the highest deforestation rate in the world) Coniferous (cone- bearing)  Grow where moisture is limited  Cold climates, moisture is unavailable in winter Boreal Forest  Northern Coniferous Forest  Slow growing  Taiga: russian, edge of forest.

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Tundra  A treeless landscape that occurs at high latitudes or on mountaintops  Growing season of 2-3 months

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Coral reefs and estuaries are among the world’s most productive and diverse ecosystems Marine Ecosystems vary mainly with depth, temperature, and salinity. Vertical Stratification  Key feature of aquatic ecosystems, mainly because light and temperature decrease rapidly with depth.

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Layers of water  Epipelagic zone  Mesopelagic zone  Bathypelagic Zone  Abyssal ZOne  Hadal Zone 

Chapter 6: Population biology  Births, immigration, deaths and emigration impact population size (B.I.D.E)

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Biotic factors are often intrinsic to an organism while abiotic factors are always extrinsic. Density-dependent effects can be dramatic. Population growth- births and immigration Negative terms- death and emigration Mortality  Some of the mortality is determined by environmental factors and some of it is determined by an organism’s physiology or its natural life span.  (Bristlecone pine trees in the mountains of California have a life span of 4,600 years).

Chapter 14  Convection in the earth’s mantle causes tectonic plate movements, earthquakes, and volcanoes.  Oceanic crusts are thinner, denser and younger than continental crust.  The rock cycle involves formation of three general rock types.  The core  Interior  It is composed of a dense, intensely hot mass of metal, mostly iron, thousands of kilometers in di=gamete.  Solid in the center but more fluid in the outer core  It generates the magnetic field that envelops the earth. 

Mantle  Surrounding the molten outer core  A hot, pliable layer of rock  Much LESS dense than the core  Contains a higher concentration of lighter elements [ oxygen, silicon and magnesium]

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Crust  The outermost layer of the earth  Lightweight, brittle  Below oceans is relatively thin (8-15km), dense, and young (less than 200 million years old) because it is constantly recycled.  Consists of rocks rich in iron, silicon, and magnesium such as basalt.  Continental crust is thicker (25-27km), less dense and older (3.8 billion). Rocks consist of granite or sandstone, generally are composed of lighter elements such as oxygen, silicon, and aluminum.

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Tectonic Plates  Convection currents in the mantle provide the force to move the overlying crust, a mosaic of huge blocks.  Ocean basins form where continents crack and pull apart.

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The Atlantic Ocean is growing slowly as Europe and Africa move away from the Americas.

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Magma  Molten Rock  Forced up through the cracks forms the new oceanic crust that piles up underwater in mid ocean ridges, creating the largest mountain ranges in the world, these ridges win around the earth for 74,000 KM.

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Subducted  “Pushed down into the mantle”  When oceanic plate converges with a continental landmass, the continental plate usually rides up over the seafloor while the oceanic plate is subducted.  The subducted plate is pushed down-- heat and pressure melt and recrystallize minerals.  Melting material can become magma.

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Volcanos  Form where the magma erupts through vents and fissures in the overlying crust;  Trenches and volcanic mountains ring the Pacific Ocean rim from Indonesia to Japan to Alaska and down the west coast of America’s forming a “RING OF FIRE”.

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Mineral  Naturally occurring, inorganic, solid element or compound with specific chemical composition and crystal structure.  Organic materials such as coal, produced by living organisms or biological processes are generally not minerals because they vary in chemical composition and lack a regular crystal structure thus are not minerals.

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Rocks  Solid, cohesive, aggregate of one or more minerals.  Within the rock, individual mineral crystals (Grains) are mixed together and held firmly in a solid mass.  Granite: a mix of quartz, feldspar, and mica crystals.

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Igneous  Solidified from magma, welling up from the earth’s interior.  Magma extruded to the surface from volcanic cents cools quickly to make basalt, rhyolite, andesite and other fine grained rocks.

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Metamorphic  Extreme heat and pressure can transform mineral structures to create new forms called metamorphic rock.  Metamorphism generally happens as buried layers of rocks are squeezed, folded, and heated by tectonic processes.

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Often show banding and folding which make them desir...