EVR1001, Exam One
EVR1001, Exam One EVR1001
University of Central Florida
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This 34 page Study Guide was uploaded by Amanda Newsome on Thursday October 6, 2016. The Study Guide belongs to EVR1001 at University of Central Florida taught by Dr. Patrick Bohlen in Fall 2016. Since its upload, it has received 141 views. For similar materials see Introduction to Environmental Science in Environmental Science at University of Central Florida.
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Date Created: 10/06/16
TEST ONE REVIEW FOR EVR1001 ALL information within this study guide was taken from: Friedland/Relyea, Essentials of Environmental Science, 2e, 2016 W.H Freeman and Company Dr. Patrick Bohlen class slideshows Chapter 1: Studying the State of Our Earth Environmental science offers important insights into our world and how we influence it. - Environment: o Environment: A sum of all the conditions surrounding us that influence life. o Environmental Science: The field that looks at interactions among humans and nature. - Living versus Nonliving: o Biotic: The living parts of the Earth (animals, plants, microorganisms) o Abiotic: The nonliving parts of the Earth (soil, air, water, etc). o Species: A group of organisms that is distinct from other groups in form, behavior, or biochemical properties. Individuals in a species can breed and produce fertile offspring. - Ecosystem: o Eco: From the Greek word ‘oikos’ house + system o System: A set of interacting components that influence one another by exchanging energy or materials. o Ecosystem: A particular location on Earth whose interacting components include biotic and abiotic components. - Environmental Scientists Monitor Natural Systems for Signs of Stress: o Ecosystem Services: Benefits humans receive from nature; such as clean water, fish, crops, etc. o Environmental Indicators: Factors that describe the current state of the environment. - Environmental Indicators: 1) Biological Diversity (Biodiversity): The variety of life forms in an environment o Genetic Diversity: Genetic variation among individuals in a population. Populations with higher genetic diversity respond better to environmental changes. o Species Diversity: The number of species in a region or in a particular type of habitat. o Ecosystem Diversity: A measure of the variety of ecosystems or habitats that exist in a particular region. o Speciation: o Background Extinction Rate: The average rate at which species go extinct over the long term 2) Food Production: o Our ability to grow food and nourish the entire human population. o Large production increase thanks to science and technology. o Huge environmental impact globally. § Healthy ecosystem supports a wide range of species, a healthy soil supports abundant and continuous food production. 3) Global Surface Temperatures and Carbon Dioxide Concentrations: o Greenhouse Gases: Gases in the atmosphere that act like a blanket, trapping heat near Earth’s surface. o Anthropogenic: caused by human activities § It is believed that the increase of greenhouse gases in the atmosphere is anthropogenic o From anthro: pertaining to humans, and genic: produced by o Anthropocene: A new global era of human influence 4) Human Population: o Current Human Population: ~7.3 billion o Over one million additional people are added to the Earth every five days. o The human population has more than doubled since 1960; and more people were added to the Earth in the 90’s than any other decade in history. 5) Resource Depletion/Pollution: o Human resource consumption depletes resources necessary for our existence o Finite non-renewable, non-recyclable resources: e.g., coal, oil, and uranium. o Finite recyclable resources: aluminum, copper, steel, etc. o Development: Improvement in human well-being through economic advancement. As economies develop, resource consumption also increases. o While an increasing amount of people do impact the environment, we must also take into consideration economic development and consumption patterns. - Sustainability o Sustainability: The practice of living on Earth in a way that allows humans to meet the needs of the present without compromising the ability of future generations to meet their needs. o Human Well-Being Depends on Sustainable Practices: § Environmental systems must not be damaged beyond their ability to recover § Renewable resources must not be depleted faster than they can regenerate. § Nonrenewable resources must be used sparingly. o Sustainable Development: Development that balances current human well-being and economic advancement with resource management for the benefit of future generations. o Ecological Footprint: A measure of how much a person consumes, expressed in area of land. § The foods we eat (i.e, meat requires more land), the water and energy we use, and the activities we perform all effect our ecological footprint § If every person on Earth lived the average lifestyle of an American, we would need five Earth’s. - Understanding Science as a Process o The Scientific Method: § Observations and questions § Hypothesis § Collecting Data § Interpreting Results § Disseminating Findings o Hypothesis: A testable conjecture about how something works, “An imaginative preconception of what the truth might be.” (P.B Medawar) o Null Hypothesis: Statement that can be proved wrong or nullified. § The textbook gives the example, “fish deaths have no relationship to something in the water” - Collecting Data by Design: o Replication: Taking repeated measurements or having multiple test subjects. o Sample Size: The number of test subjects or times the measurement is repeated. o Scientists try to make sure the sample size is large to reduce change effects. - Data Measurement o Accuracy: Refers to how close a measured value is to the actual/true value (hits the target) o Precise: How close to one another the repeated measurements of the same sample are(if all arrows are in the same area it is precise) o To be both accurate and precise, arrows would need to be on/near the target and near one another. o Uncertainty: A measure of how sure we are that a measurement represents the true value. - Theory and Natural Laws o Theory: A hypothesis that has been repeatedly tested and confirmed by multiple groups of researchers and has reached wide acceptance o Natural Law: A theory to which there are no known exceptions and which has withstood rigorous testing (such as the law of gravity). o Controlled Experiments: An experiment conducted in controlled conditions, such as in a laboratory. o Natural Experiments: Using effects of natural events, such as a volcano, as an experimental treatment in an ecosystem. - Environmental Science Presents Unique Challenges o It is difficult to establish “baseline” because there is no “control” planet. o It is sometimes difficult deciding whether something is better or worse for the environment than something else. o Environmental issues are complex, the cause and effect are not always clear. o Environmental choices are dictated by human desires/needs. o Environmental science issues require political and social solution, not just science. Chapter 2: Environmental Systems - Nature of Matter: o Matter: Anything that takes up space and has mass; the “stuff” that makes up the entire universe. o Mass: A measure of the amount of matter an object contains. o Weight: The force that results from the action of gravity on mass. o Atom: An atom contains a nucleus, in which protons (positively charged) and neutrons (neutrally charged) stay. Outside of the nucleus, is the electron cloud in which electrons (negatively charged) sit on electron shells. o Molecule: A particle with more than one atom. o Compound: Molecule that contains more than one element. o Atomic Number: Amount of protons in the nucleus of an element o Mass Number: Total number of protons and neutrons in an element o Isotopes: Atoms of the same element that have different numbers of neutrons in the nucleus. § Have different atomic masses, but same atomic number. § Isotopic Signature: Ratio of different isotopes in a substance. o Radioactive Decay: The spontaneous release of material from the nucleus of an unstable isotope. - Radioactivity o Half Life: Time it takes for one-half of the original radioactive parent atoms to decay. o Half Life is important because: § Some radioactive elements emit radiation harmful to living things. § It allows scientists to determine the length of time that a radioactive element may be dangerous. - Chemical Bonds: o Covalent Bonds: Elements that form compounds by sharing electrons. o Ionic Bonds: Elements that form compounds by transferring electrons from one element to another. § One atom becomes electron deficient (positively charged) and one atom becomes electron rich (negatively charged) § These charges atoms are called ions § Ionic bonds are not usually as strong as covalent bonds o Hydrogen Bonds: A weak chemical bond that forms when hydrogen atoms that are covalently bonded to one atom are attracted to another atom on another molecule o Polar Molecules: A molecule in which one side is more positive and the other side is more negative - Properties of Water o Water freezes at 32 degrees Fahrenheit and boils at 212 degrees Fahrenheit o Surface Tension: Results from cohesion between water molecules at the water surface. o Capillary Actions: When adhesion of water molecules to a surface is stronger than cohesion between the molecules. o Water as a Solvent: Many substances dissolve in water because their polar molecules bond easily with the polar water molecules. - Acidic, Bases, and pH 1 pH Unit = 10-fold change in acidity o 2 pH Units = 100-fold change in acidity o Acid: A substance that contributes hydrogen ions (H+) to a solution. o Base: A substance that contributes hydroxide ions (OH-) to a solution. o Logarithmic Scale § 1-6: acidic § 7: neutral § 8-14: basic (alkaline) o Chemical Reaction: Occurs when atoms separate from the molecules of which they are a part of or recombine with other molecules. o Inorganic Compounds: Compounds that do not contain carbon, or if they do contain carbon it is not bonded to hydrogen. o Organic Compounds: Compounds that have carbon-carbon and carbon-hydrogen bonds. - Law of Conservation of Matter: Matter cannot be created or destroyed; it can only change form. - Biological Molecules and Cells: o Carbohydrates: Compounds composed of carbon, hydrogen, and oxygen atoms. o Proteins: Made up of long chains of nitrogen-containing organic molecules called amino acids. § Are critical in structural support, energy storage, internal transport, and defense against foreign substances o Nucleic Acids: Organic compounds found in all living things. § DNA: genetic material organisms pass on to their offspring that contains the code for reproducing the components of the next generation § RNA: translates the code stores in the DNA and allows for the synthesis of proteins o Lipids: Biological molecules that do not mix with water. For instance, fats, oils, steroid hormones, and waxes. o Cell: highly organized living entity that consists of the four types of macromolecules and other substances in a watery solution, surrounded by a membrane. - Energy o Energy: Is the ability to do work. § Energy = power x time § Measured in Joules o Power: The rate at which work is done § Power = work / time § Mechanical, electrical, etc. o Energy is a fundamental component of all environmental systems. o Joule: amount of energy used when a 1-watt light bulb is turned on for 1 second Common Units of Energy and their Conversion to Joules UNIT DEFINITION RELATIONSHIP TO JOULES calorie Amount of energy it takes to heat 1 gram of water 1degreeC Calorie Food calorie; always 1 Calorie = 1000 shown with a capital calories = 1 kilocalorie ‘C’ (kcal) British Thermal Unit Amount of energy it (BTU) takes to heat 1 pound of water 1degreeF Kilowatt- hour Amount of energy (kWh) expended by using 1 kilowatt of electricity for one hour I HAVE ONLY ENTERED IN INFORMATION FOR THE CHART THAT DOCTOR BOHLEN SAID WAS NECESSARY FOR THE TEST** - Forms of Energy o Kinetic Energy: Energy of motion o Potential Energy: Stored energy o Chemical Energy: Potential energy contained in chemical bonds o Temperature: The measure of the average kinetic energy of the atoms and molecules making up a substance. - Thermodynamics: o First Law: Energy can neither be created nor destroyed o Second Law: When energy is transformed, the quantity of energy remains the same, but its ability to do work declines. - Energy o Energy Efficiency: The ratio of the amount of work that is done to the total amount of energy that is introduced into the system. o Energy Quality: The ease with which an energy source can be used for work. o Entropy: All systems move toward randomness rather than toward order. § Unless energy from outside the system is added to create order Energy conversions underlie all ecological processes o Open System: Exchanges of matter or energy occur across system boundaries (i.e, a lake, Earth, etc) o Closed System: Matter and energy exchanges across system boundaries do not occur (i.e, a lightbulb). o Steady State: In a system, when input equals output, it is said to be in a steady state. Chapter 3: Ecosystem, Ecology, and Biomes - Ecosystem Ecology: o Ecosystem: A particular location on Earth distinguished by its particular mix of interacting biotic (living) and abiotic (nonliving) components. Energy flows through Ecosystems: - Photosynthesis and Respiration o Photosynthesis: producers use solar energy to convert carbon dioxide and water into glucose § Solar Energy + 6 H20 + 6 CO2 à C6H12O6 (glucose) +6 02 § Performed by plants, algae, and some bacteria. o Respiration: they run photosynthesis backward to recover the solar energy stored in glucose § Energy + 6 H20 + 6 CO2 ß C6H12O6 + 6 O2 § Performed by all organisms o All organisms including producers, carry out respiration. However, only producers are able to carry out photosynthesis. o Producers: Plants, algae, or other organisms that use the energy of the sun to produce usable forms of energy - Trophic Levels, Food Chains, and Food Webs o Consumers/Heterotrophs: Incapable of photosynthesis and must obtain their energy by consuming other organisms § Heterotrophs that consume producers are called herbivores or primary consumers (i.e, zebras, grasshoppers, etc) § Heterotrophs that obtain their energy by eating other consumers are called carnivores or secondary consumers (i.e, lions, hawks, etc) § Tertiary Consumers: A carnivore that eats secondary consumers § Scavengers: carnivores that eat dead animals such as vultures § Detritivores: an organism (such as a dung beetle) that specialize in breaking down dead tissue and waste products into smaller particles o We call these successive levels of organisms consuming one another trophic levels o The sequence of consumptions from producers through tertiary consumers is known as food chain § Helps us visualize how energy and matter move between trophic levels o Food Web: - Ecosystem Productivity: o The amount of energy available in an ecosystem determines how much life the ecosystem can support o Gross Primary Productivity (GPP): The total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time. o Net Primary Productivity (NPP): The energy capture (GPP) minus the energy respired by the producers. § NPP = GPP – respiration by producers § Think of GPP and NPP in terms of your paycheck; GPP is the amount of the check and NPP is the actual amount you take home after taxes - Energy Transfer Efficiency and Trophic Pyramids o Ecological Efficiency: The proportion of consumed energy that can be passed from one trophic level to another. o Biomass: Energy in an ecosystem § The NPP establishes the rate at which biomass is produced ove a given amount of time. o We can represent the distribution of biomass among trophic levels using a trophic pyramid - Matter Cycles o Biosphere: The combination of all ecosystems on Earth form the biosphere o The Earth may be grossly divided into four compartments: earth (soil and rock), water, the atmosphere, and living things. § Geosphere, hydrosphere, atmosphere, and biosphere o All matter cycles involve the movement or materials from one compartment to other compartments. o Biogeochemical Cycles: The cycling of matter through the biosphere § Bio: life § Geo: Earth § Chemical: matter - The Hydrologic Cycle o The movement of water through the biosphere 1) Solar energy heats Earth and causes evaporation 2) Evaporated water cools and turns into clouds 3) Water returns to Earth as precipitation (rain, snow, or hail) 4) Precipitation falling on land is taken up by plants, run off along the land surface, or percolates into the soil and enters the groundwater. - The Carbon Cycle 1) Producers convert CO2 into sugars 2) Sugars are converted back into CO2 3) Some carbon can be buried 4) Human extraction of fossil fuels brings Carbon to Earth’s surface, where it can be combusted. 5) CO2 in the atmosphere and CO2 in the water are constantly exchanged. 6) Combustion converts fossils fuels and plant material into CO2 - The Nitrogen Cycle 1) Nitrogen Fixation 2) Assimilation 3) Ammonification 4) Nitrification 5) Denitrification - Ecosystems and Disturbance o Disturbance: An event that is caused by physical, chemical, or biological agents and that results in changes in population size or community composition. o Resistance: Is a measure of how much disturbance an ecosystem can tolerate without significantly changing the flows of energy and matter. o The rate at which an ecosystem returns to its original state after a disturbance is termed as resilience o Natural Ecosystem Disturbances: Include hurricanes, volcanic eruptions, forest fires, etc. o Anthropogenic Ecosystem Disturbances: Include human settlements, agriculture, air and water pollution, clear-cutting of forests, as well as strip mining. o In a human dominated world, natural and anthropogenic disturbances become intertwined. o Watershed: All the land in a given landscape that drains into a particular stream, river, lake, or wetland. - Global Processes Determine Weather and Climate o Weather: The short term conditions of the atmosphere in a local area (temperature, humidity, wind speed, precipitation, etc) o Climate: The average weather that occurs in a given region over a long period (typically several decades) - Earth’s Atmosphere o Troposphere: The layer closest to Earth’s surface extending roughly 16 kilometers (10 miles) above the Earth. § Densest later of the atmosphere: most of the atmosphere’s nitrogen, oxygen, and water vapor occur here § Earth’s weather occurs here o Stratosphere: Above the troposphere, extends roughly 16-50 kilometers (10-31 miles) § Ozone (pale blue gas composed of molecules made up of three oxygens atoms) forms a layer within the stratosphere - Distribution of heat and Precipitation o Unequal Heating of Earth: § Warming does not happen evenly across the planet § Albedo: the percentage of incoming sunlight that is reflected from a surface § The higher the albedo of a surface, the more solar energy it reflects, and the less it absorbs. § Earth has an average albedo of about 30% o Atmospheric Convection Currents: § Uneven heating drives the circulation of air in the atmosphere. § Density: less-dense air rises, denser air sinks. § Water Vapor Capacity: Warm air has a higher capacity for water vapor than cold air. § Latent Heat Releases: When water vapor in the atmosphere condenses into liquid water, energy is released. This is the same energy (latent heat) that was required to change liquid water to water vapor during evaporation. § Figure 3.12 in the Textbook: 1) At the equator, the sun heats the moist tropical air, causing it to rise. 2) The rising air experiences adiabatic cooling, which causes water vapor to condense into rain and fall back to Earth. 3) The condensation of water vapor produces latent heat release. This causes the air to expand and rise farther up into the atmosphere. 4) The warm, rising air displaces the cooler, drier air above it to the north and the south. 5) The cool, dry air sinks and experiences adiabatic heating. It reaches Earth’s surface as warm, dry air, and then flows back toward the equator. - Earth’s Rotation and the Coriolis Effect o Coriolis Effect: The deflection of an object’s path due to Earth’s rotation. o Prevailing winds are produced by a combination of atmospheric convection currents and the Coriolis effect. - Ocean Currents: o Ocean currents are driven by a combination of temperature, gravity, prevailing winds, the Coriolis effect, and the locations of continents. o Warm water, just as warm air, expands and rises. o Gyres: Large-scale patterns of water circulation. The ocean surface currents rotate in a clockwise direction in the Northern hemisphere and a counter clockwise direction in the Southern hemisphere. o Upwelling: The surface currents diverge, or separate from one another, causing deeper waters to rise and replace the water that has moved away. § The deep waters bring with them nutrients from the ocean bottom that support large populations of producers § Upwelling also occurs with wind parallel to the coast o Thermohaline Circulation: drives the mixing of surface water and deep water § Scientists believe this process is crucial for moving heat and nutrients around the globe o El Niño-Southern Oscillation or ENSO: § Every 3-7 years, Earth’s atmosphere and ocean surface currents interact in the tropical Pacific Ocean to reverse direction. § Globally the impact of El Niño result in cooler and wetter conditions in the Southeastern US and unusually dry weather in Southern Africa and Southeast Asia, which can often lead to floods, droughts, and other natural disasters. o Rain Shadows: § A region with dry conditions found on the leeward side of a mountain range as a result of humid winds from the ocean causing precipitation on the windward side. - Variations in Climate Determine Earth’s Dominant Plant Growth Forms o Biomes: Have a particular combination of average annual temperature ad annual precipitation and contain distinctive plant growth forms that are adapted to that climate. o Robert Harding Whittaker (1920,1980), an American Ecologist graduated from Cornell University. - Terrestrial Biomes o Three Categories: Tundra and Boreal Forest, Temperate, and Tropical. o Tundra: § Cold, treeless biome with low growing vegetation. The soil is completely frozen during the winter. § Short, four month growing season. § The underlying subsoil, known as permafrost, is an impermeable, permanently frozen later that prevents water from draining and roots from penetrating. o Boreal Forest: § Mostly coniferous (cone-bearing) evergreen trees that can tolerate cold winters and short growing seasons. § Found between about 50 and 60 N in Europe, Russia, and North America § Plant growth more constrained by low temperature than precipitation. § The soil is nutrient-poor due to slow decomposition. o Temperate Rainforests: § Coastal Biome ocean currents moderate temperature fluctuations and provide water vapor § Moderate temperatures and high precipitation § 12 month growing season in which winters are rainy and summers are foggy § Mild temperatures and high precipitation supports growth of gigantic trees o Temperate Seasonal Forests: § Receive over 1 meter (39 inches) of precipitation annually. § Found in Eastern US, Japan, China, Europe, Chile, and Eastern Australia. § Dominated by broadleaf deciduous trees such as beech, male, oak, and hickory. § Warmer Temperatures = more decomposition, so soils generally contain more nutrients than those of boreal forests. o Woodland/Shrubland: § “Mediterranean” climate § Hot and dry summers / mild and rainy winters § 12 month growing season but plant growth constrained by low summer precipitation cool winter temperatures. § Plants of this biome are well adapted to both fire and drought § Soils are low in nutrients because of leaching by the winter rains. § Major agricultural uses are grazing animals and growing drought tolerant deep rooted crops such as grapes o Temperate Grassland/Cold Desert: § Great Plains of USA, South America, central Asia, and eastern Europe. § Cold harsh winters / dry hot summers § Dominated by grasses and non-woody flowering adapted to wildfires and frequent grazing § Lowest average annual precipitation of any temperate biome o Tropical Rainforest: § Located between 20 N and S of the equator. § Central and South America, Africa, Southeast Asia, and Northeast Australia § Frequent rainfall, warm and wet with steady temperatures. § Most biodiversity than any other terrestrial biome / two- thirds of Earth’s terrestrial species o Tropical Seasonal Forest/Savanna: § Warm temperatures and distinct wet and dry seasons § Central America, Atlantic Coast of South America, Southern Asia, Northwestern Australia, and sub-Saharan Africa § Fairly fertile soils but low precipitation constrains plant growth § Grasses along with scattered deciduous trees are common o Subtropical Desert: § 30 N and S with hot temperatures and extremely dry conditions § Mojave Desert in Southwestern United States, Sahara, Middle East, Great Victoria Desert of Australia. § Cacti, succulents, and euphorb plants! - Aquatic Biomes o Categorized by salinity, depth, and water flow. o Lakes and Ponds: § Littoral Zone: The shallow area of soil and water near the shore where algae and emergent plants grow. § Limnetic Zone: Open water, where rooted plants can no longer survive. Phytoplankton are the only photosynthetic organisms. This zone extends to as deep as sunlight can penetrate. § Profundal Zone: The zone in which sunlight cannot penetrate therefore producers cannot survive. § Benthic Zone: The muddy bottom of a lake or pond beneath the limnetic and Profundal zone. o Freshwater Wetlands § Submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation throughout. § Includes swamps, marshes, and bogs. § Swamps: Wetlands that contain emergent trees § Marshes: Wetlands that contain primarily non-woody vegetation § Bogs: Very acidic wetlands that typically contain sphagnum moss and spruce trees o Salt Marshes: § Found along the coast in temperate climates § Contain non-woody emergent vegetation § Most productive biomes in the world § Mostly found in estuaries (areas along the coast where the fresh water of rivers mixes with salt water from the ocean) § Provide important habitat for spawning fish and shellfish o Mangrove Swamps: § Found along tropical and subtropical coasts and contain trees whose roots are submerged in water § Mangrove trees are salt tolerant and help protect the coastlines from erosion and storm damage o Intertidal Zone: § Narrow band of coastline that exists between the levels of high and low tide § Range from steep, rock areas to broad, sloping mudflats § Waves that crash onto the shore of this biome can make it difficult for organisms to hold on and not get washed away o Coral Reefs: § Found in warm shallow waters beyond the shoreline § Earth’s most diverse marine biome, even though coral reefs are found in waters that are relatively poor in nutrients and food § Coral Bleaching: when the algae inside the coral dies; scientists believe this is due to a combination of disease and environmental change (change in ocean temperature, runoff and pollution, overexposure to sunlight, and extreme low tides). o The Open Ocean: The depth that light can penetrate in the open ocean is dependent on the amount of sediment and algae suspended in the water. § Photic Zone: The zone that receives enough light to allow photosynthesis to occur. § Aphotic Zone: The deeper water that lacks enough light to allow for photosynthesis. § Chemosynthesis: The process that occurs in the aphotic zone when some species of bacteria use methane and hydrogen sulfide to generate energy. Chapter 4: Evolution, Biodiversity, and Community Ecology Evolution is the mechanism underlying biodiversity - Diversity exists at different scales o It is Important to Understand: § Factors that generate diversity § The consequences of diversity for environmental systems o Ecosystem Diversity: The variety of ecosystems within a given region. o Species Diversity: The number of species in a region o Genetic Diversity: Genetic variation among individuals in a population. Populations with higher genetic diversity respond better to environmental changes. - Species Richness and Species Evenness o Species Richness: The number of species in a given area § Used to give an approximate sense of the biodiversity of a particular place o Species Evenness: The relative abundance of the different species in an area (dominance). § Tells us whether a particular ecosystem is numerically dominated by one species or whether all of its species have similar abundances - Evolution o Evolution: The genetic composition of a species changes over time. o Mechanism underlying biodiversity. o Microevolution: Evolution occurring within a species o Macroevolution: Evolution that gives rise to new species or larger groups, such as genera, family, phylum, class, etc. o Evolution by Artificial Selection: § The environment determines which individuals are most likely to survive and reproduce. o Darwin’s Theory of Evolution by Natural Selection: 1) Individuals vary 2) Some of this variation is inherited 3) Some inherited variation makes some individuals better adapted to survive 4) Better adapted individuals are more likely to survive and reproduce, passing on their inherited advantage 5) Over generations, genes of reproductively successful organisms will become more frequent in members of other species - Creating Genetic Diversity o Genes: Hereditary unit representing a DNA sequence located on chromosomes within the cell nucleus. § An organism’s genes determine the range of possible traits that it can pass down. § They code for inherited traits, which may or may not be expressed in a physical organism. o Genotype: The complete set of genes in an individual. All the genes within an organism are also collectively called the genome. o Phenotype: Actual set of traits expressed in that individual - Random Processes: o Mutation: A random change in genetic code produced by a mistake in the copying process § Some are random § Some are caused by external agents § Most are detrimental o Genetic Drift: Change in the genetic composition of a population over time as a result of random mating. § Can be particularly important in small populations o Bottleneck Effect: A reduction in the genetic diversity of a population caused by a reduction in its size § Low genetic variation can cause several problems § Population bottleneck: a drastic reduction in the size of a population (the amount of genetic variation is therefore also reduced) § In some cases, after a species has been forced through a bottleneck, low genetic diversity can cause it to decline to extinction o Founder Effect: A change in a population descended from a small number of colonizing individuals § Random process that is not based on differences in fitness § Fitness: ability to survive and reproduce § Adaptations: Traits that improve an individual’s fitness - 4 Factors Affecting the Pace of Evolution 1) The rate of environmental change 2) The amount of genetic variation within a species 3) The size of the population involved 4) How fast the species reproduces (generation time) - Evolution Shapes Ecological Niches and Determines Species Distributions o Range of Tolerance: The conditions under which a species performs best § Limits to the abiotic conditions they can tolerate, such as extremes of temperature or humidity § Narrower tolerances can make species more vulnerable to environmental changes o Niches: The range of abiotic and biotic conditions under which a species lives; determines species distribution, or areas where it lives § Niche Generalist: Species that live under a wide range of conditions (such as a raccoon) § Niche Specialist: Species that live only in specific habitats (such as Florida Scrub Jay) § Niche differences stabilize communities, allow species to coexist, and help maintain biodiversity. - The Fossil Record o Fossil: The organic remains of an organism preserved by being replaced by minerals in rock. o Mass Extinction: Which large numbers of species went extinct over relatively short periods of time o What caused the first five mass extinctions? § Causes not known for all events § Effect was on a massive scale § 251 million years ago, 90% of marine animals and 70% of land species went extinct. o The Sixth Mass Extinction § Many scientists feel that we are in our sixth mass extinction, starting in the last two decades. § Estimates of possible extinction rates vary widely from 2-25% by 2020 § Scientists agree that this sixth mass extinction is caused by humans - Nature Exists at Several Levels of Organization o Individual: Survival and reproduction- the unit of natural selection o Population: Population dynamics- the unit of evolution - Population Ecology o Population ecologists study the factors that regulate population abundance and distribution. o Population Size: The total numbers of individuals within a defined area at a given time o Population Density: The number of individuals per unit area at a given time o Population Distribution: How individuals are distributed with respect to one another § Random distribution, uniform distribution, and clumped distribution. o Population Sex Ratio: The ratio of males to females o Population Age Structure: How many individuals are in given age categories - Factors that Influence Population Size o Density-Dependent Factors: The size of the population will influence an individual’s probability of survival o Density-Independent Factors: The size of the population has no effect on the individual’s probability of survival. § Have the same effect on the individual’s likelihood of survival and amount of reproduction, at any population size. Hurricane’s, tornados, floods, etc. - Population Growth Models o Mathematical equations used to predict population size at any given time. o Growth Rate: The average number of offspring individuals produce in a given time period, minus deaths of individuals or offspring during the same period. o Intrinsic Growth Rate: Under ideal conditions, with unlimited resources, the maximum potential for growth (denoted as r) for a population. o Exponential Growth Model: A growth model that estimates a population’s future size after a period of time, based on the intrinsic growth rate and the number of reproducing individuals currently in the population. o J Shaped Curve: When populations are not limited by resources, their growth can be very rapid. More births occur with each step in time, creating a J-shaped curve. o Logistic Growth: Population grows exponentially, but slows as the population approaches the carrying capacity. o S Shaped Curve: When graphed, the logistic growth model looks like an “S.” o Carrying Capacity (K): The limit of how large a population can be sustained by the limiting resources - Overshoot and Die-Off: o If limiting resources become scarce, the population can overshoot the carrying capacity. o This will result in a die-off, or population crash. o An example is reindeer on St. Paul Island, Alaska. - Reproductive Strategies o K-Selected Species: The population of a species that grows slowly until it reaches the carrying capacity. § Abundance determined by carrying capacity “K” o R-Selected Species: Populations grow quickly, and often experience overshoot and die-offs. § “R” denotes the intrinsic growth rate § Example: mosquitos, rabbits. - Community Ecologists Study Species Interactions o Competition: Individuals struggling to obtain a limiting resource. § Competitive Exclusion Principle: Two species competing for the same limiting resource cannot coexist. This can lead to resource partitioning (in which two species divide a resource based on differences in the species’ behavior or morphology) o Predation: Refers to the use of one species as a resource by another species. § True Predators: Kill their prey § Herbivores: Consume plants as prey § Parasites: Live on or in the organism they consume. If they cause disease, they are pathogens. § Parasitoids: Lay eggs either in or on other organisms, and offspring kill the host. o Commensalism: One species benefits while the other is neither harmed nor helped. - Symbiosis: o Symbiotic Relationships: Two species live in close association. o Commensalism, mutualism, and parasitism are all examples of symbiotic relationships. Type of Interaction: Species 1: Species 2: Competition - - Predation + - Mutualism + + Commensalism + 0 - Keystone Species: o Keystone Species: A species whose role in its community is far more important than its relative abundance might suggest. o Ecosystem Engineers: Modify their environment in ways that create and maintain habitat. o Ecological Succession: § Primary Succession: Ecological succession occurring on surfaces that are initially devoid of soil § Secondary Succession: The succession of plant life that occurs in areas that have been disturbed but have not lost their soil § Aquatic Succession - The Theory of Island Biogeography o Distance Effect: The farther an island is from the continent, the fewer species find and colonize it. o Larger islands have higher immigration rates – they are fatter targets o Larger islands have lower extinction rates – more spaces allows for larger populations Chapter 5: Human Population Growth - Two Books discussing human population growth o An Essay on the Principle of Population by Thomas Malthus (1798) o The Population Bomb by Dr. Paul Ehrlich (1968) - Many Factors Drive Human Population Growth o Demography: The study of human populations and population trends o 5 Factors: § Changes in population size § Fertility § Life Expectancy § Age Structure § Migration - Birth and Death Rates: o Crude Birth Rate (CBR): The number of births per 1000 persons per year. o Crude Death Rate (CDR): The number of deaths per 1000 persons per year. o Population Growth Rate: § Global Population Growth Rate = [CBR-CBD] / 10 = growth rate in % - Changes in Population Size o Doubling Time: The number of years it takes a population to double o The Rule of 70 can be used to estimate the doubling time (DT) in years. § Doubling time (in years) = 70/growth rate - Fertility o Total Fertility Rate (TFR): An estimate of the average number of children that each woman in a population will bear o Replacement Level Fertility: The total fertility rate required to offset the average number of deaths in a population and for the current population size to remain stable. o In developed countries, the replacement level fertility is typically 2.1 - Life Expectancy: o Life Expectancy: The average number of years that an infant born in a particular year in a particular country can be expected to live, given the current average life span and death rate of that country. § Usually reported in three different ways: for overall population, for males, and for females o Infant Mortality Rate: The number of deaths of children under one year of age per 1000 live births o Child Mortality Rate: The number of deaths of children under age five per 1000 live births - Age Structure Diagrams o Visual representations of age structure within a country for males and females o Each horizontal bar of the diagram represents a five-year age group o The total area of all the bars in the diagram represent the size of the whole population - Migration o A country may experience a change in its population due to migration o Net Migration Rate: The difference between immigration and emigration in a given year per 1000 people in a country - The Demographic Transition o The theory of The Demographic Transition suggests that as a country moves from subsistence economy to industrialization and increased affluence, it undergoes a predictable shift in population growth. o The Four Stages: § Phase 1: Slow population growth because there are high birth rates and high death rates that offset each other § Phase 2: Rapid population growth because birth rates remain high but death rates decline due to better sanitation, clean drinking water, increased access to foods/goods, and health care § Phase 3: Stable population growth as the economy and educational systems improves and people have fewer children § Phase 4: Declining population growth because the relatively high level of affluence and economic development encourage women to delay having children - Family Planning: o Family Planning: The regulation of the number of offspring through the use of birth control § As more women become more educated, the TFR (total fertility rate) tends to drop o Three E’s: § Employment, education, and equality - The IPAT Equation o Impact = population x affluence x technology § Affluence: money, goods, or property - Measures of Affluence o Gross Domestic Product (GDP): The value of all products and services produced in a year in that country § GDP is made up of consumer spending, investments, government spending, and exports minus imports § A country’s GDP often correlates its pollution levels - Sustainable Development is a common, if elusive, goal o Global consumption threatens ecosystem stability and services Chapter 6: Geologic Processes, Soils, and Minerals - Formation of Earth and the Solar System: o Consolidation of cosmic dust cloud o Planets and Sun begin to form o Present-day solar system - The Earth’s layers: o Core: Innermost zone of the planet, largely composed of nickel and iron o Mantle: Above the core, contains magma (molten rock) o Crust: The outermost layer of the planet § Elemental Composition: • Aluminum: 8% • Iron: 6% • Magnesium: 4% • Calcium: 2.4% • Oxygen: 46% • Silicon: 28% • Other: 5.6% o Asthenosphere: The outer part of the mantle; semi-molten rock o Lithosphere: The brittle outermost layer of the planet, approximately 100 kilometers thick - The Dynamic Earth o The Earth’s geologic cycle consists of three cycles: the rock cycle, the tectonic cycle, and soil formation. o Convection and Hotspots: § Convection: Heat from Earth’s core causes plumes of hot magma to well upward from the mantle § Hot Spots: Intra-place locations where molten material from the mantle reach the lithosphere o Theory of Plate Tectonics: § Plate Tectonics: The Earth’s lithosphere is divided into plates, which are in constant motion. § The Tectonic Cycle: The sum of the processes that build up and break down the lithosphere § Alfred Wegener (German meteorologist), in 1912 published a hypothesis proposing that the world’s continents had once been joined in a single landmass, which he called “Pangea” • Identical rock formations are found on both sides of the Atlantic Ocean • Fossils of the same species have been collected from different continents • Earth’s history is measured by the geologic time scale - Types of Plate Contact: o Divergent Plate Boundaries: Plates move apart from one another § Seafloor Spreading: The formation of new ocean crust as a result of magma pushing upward and outward from Earth’s mantle to the surface o Convergent Plate Boundaries: Plates move toward one another and collide, with great force o Transform Plate Boundaries: Plates move sideways past each other - Faults and Earthquakes o Faults: A fracture in rock across which there is movement § Fault Zones: Large expanses of rock where movement has occurred, form in the brittle upper lithosphere where two plates meet. o Earthquakes: Occur when the rocks of the lithosphere rupture unexpectedly along a fault § Earthquakes are common in fault zones, which are also called areas of seismic activity § The epicenter of an earthquake is the exact point on the surface of Earth directly above the location where the rock ruptured o Richter Scale: A measure of the largest ground movement that occurs during an earthquake § Like the pH scale, the Richter scale is logarithmic § A value increases by a factor of 10 for each unit increase - The Rock Cycle: o The rock cycle recycles minerals and elements o Igneous Rocks: rocks that form directly from magma § Intrusive Igneous: Forms within Earth as magma cools § Extrusive Igneous: Form when magma cools above the surface of Earth o Sedimentary Rocks: Sediments such as mud, sand, or gravel are compressed by overlying sediment § Sandstone or limestone o Metamorphic Rock: Sedimentary, igneous, or other metamorphic rocks subjected to high temperatures and pressures o Weathering: Rocks degraded by air, water, certain chemicals, or biological agents § Physical Weathering: Mechanical breakdown of rocks or minerals § Chemical Weathering: Breakdown of rocks or minerals by chemical reactions o Erosion: Physical removal of rock fragments from a landscape or ecosystem, by wind, water, glaciers, and living organisms o Deposition: Accumulation or depositing of eroded material such as sediment, rock fragments, or soil - Soil: o Ecosystem Services provided by soil: § Medium for plant growth § Breaks down organic material and recycles nutrients § Habitat for a variety of organisms § Filters waters o Parent Material: the rock material underlying it from which its inorganic components are derived o Soil Horizons: § O Horizon (Organic layer): composed of the leaves, needles, twigs, and animal bodies on the surface § A Horizon (topsoil): Zone of organic materials and minerals mixed together § B Horizon (subsoil): Composed primarily of mineral material with very little organic matter § C Horizon (parent material): The least weathered horizon; similar to the parent material o Soil Texture: The percentage of sand, clay, and silt the soil contains. § Be comfortable and able to read the soil texture chart! § The texture of a soil is determined by the percentage of sand, silt, and clay it contains o Soil Porosity: How quickly the soil drains, due to size of pore spaces in the soil - Chemical Properties of Soil: o Cation Exchange Capacity (CEC): The ability of a particular soil to absorb and release cations (+ charged mineral ions), also known as nutrient holding capacity o Soil Bases: Calcium, magnesium, potassium, and sodium o Soil Acids: Aluminum and hydrogen o Base Saturation: The proportion of soil bases to soil acids - Types of Mining: o Reserves: Known quantity of a resource that can be economically recovered o Surface Mining: Removing minerals that are close to Earth’s surface § Strip Mining: Removes strips of soil and rocks to expose ore. Produces waste tailings (unwanted waste material) § Open Pit Mining: Creates large pit or hole in the ground that is visible from the surface § Mountain Top Removal: Removes the entire top of a mountain with explosives § Placer Mining: Searching for metals and stones in river sediments; gold is often recovered in this manner o Subsurface Mining: Mining for resources that are 100 meters or more below Earth’s surface o Mining Problems: § Surface mining is generally more damaging to the environment § Subsurface mining is significantly more dangerous to miners § In general, mining legislation does not address environmental issues, with the exception of coal mining Chapter 7: Land Resources and Agriculture Human land use impacts the environment in several ways. - The Tragedy of the Commons o Proposed by Garnett Hardin in 1968 o The Tragedy of the Commons: “The tendency of a shared, unregulated, public resource to become depleted by people acting in self -interest for short term gain” § Use of the commons below the carrying capacity of the land results in a benefits for all users. § If one or more users overuse the land, going over its’ carrying capacity, the commons become less flourishing. The cost of the degradation is incurred by all users. § If practices are continued on this way and nothing is done in terms of environmental impacts and land use practices, the commons land will eventually lose the ability to support the activity. o Externalities: A cost or benefit of a good or service not included in the purchase price of that product or service. § Negative Externalities: Such as pollution along with other “tragedy of the commons” effects are central to environmental science. § The “public” usually ends up paying. o Maximum Sustainable Yield (MSY): The maximum amount of a renewable resource that can be harvested without compromising the future availability of that resource. Land Management practices vary according to their classification and use - Protected Lands: o The United States has 28,800 protected areas covering 294,476 km^2 (499,800 sq mi). o These include state, federal, and private protected areas. o This makes up 14% of total land area. § 9,420,412 acres of protected land in Florida § Roughly makes up 27% of total state land area - Public Lands: o National Parks: Managed for scientific, educational, and recreational use, and sometimes for their beauty or unique landforms. o Managed Resource Protected Areas: Managed for the sustained use of biological, mineral, and recreational resources. o Habitat/Species Management Areas: Actively managed to maintain biological communities. o Strict Nature Reserves and Wilderness Areas: Established to protect species and ecosystems. o Protected Landscapes and Seascapes: Permit nondestructive use of natural resources while allowing for tourism and recreation. o National Monuments: Set aside to protect unique sites of special natural or cultural interests. - Land Use in The United States • Timber Production: 23% • Defense: 1% • Urban, Residential, and Transportation: 4% • Recreational and Wildlife Lands: 11% • Cropland: 20% • Forest Grazing Land: 6% • Grassland/Grazing Land: 25% • Unused Land (tundra, desert, etc): 10% o Rangeland: § Dry, open grasslands that are primarily used for cattle grazing § Cattle and sheep can be raised on land that is too dry to farm § Livestock can damage stream banks and pollute surface waters and overgrazing can quickly denude a region of vegetation § Florida has 5.1 million acres o Forests: § Areas that are dominated by trees and/or other wood-like plants § Roughly 73% of commercial forests in the United States are privately owned o National Forests: § Commercial logging companies can use U.S national forests, usually in exchange for a percentage of their revenues. § The federal government typically spends more money on management and building and maintaining logging roads than it receives in logging revenue. o Timber Harvest Practices: § Clear-Cutting: Removing all/almost all of the trees in an area. § Selective-Cutting: Removing single trees or relatively small numbers of trees from a forest, creating many small openings. § Ecologically Sustainable Forestry: Seeks to maintain social and economic benefits of forest including recreation and protection of biodiversity. o National Parks, Refuges, and Wilderness Areas § National Parks: Based on multiple-use principle and intended to preserve natural resources. § National Wildlife Refuges: Managed for the purpose of protecting wildlife. § National Wilderness Areas: Set aside to preserve large tracts of intact ecosystems or landscapes o Federal Regulation of Land-Use: § National Environment Policy Act (NEPA): Mandates an environmental assessment of all projects involving federal money or permits. § Environmental Impact Statement (EIS): Outlines the scope and purpose of the project. § Environmental Mitigation Plan: Outlines how the developer will address concerns raised by the project’s impact on the environment. § Endangered Species Act: Protects species from extinction. o Residential Land: § Suburban: Lower population density areas surrounding metropolitan centers. § Exurban: Similar to suburban areas, but unconnected to any central city or densely populated area. § Since 1950, more than 90% population growth in metropolitan areas occurred in suburbs. o Urban Sprawl: The four main causes of urban sprawl in the USA are 1) Cars and highway construction 2) Living costs (more land and a larger house for less money) 3) Urban Blight (city revenues shrinks as people move to the suburbs) 4) Government policies o Government Policies: § Highway Trust Fund: Since 1956, federal gasoline tax pays for construction and maintenance of roads and highways. • Highways encourage people to live further from where they work § Zoning: Planning tool that limits types of development that can occur in an area (for instance: residential, agricultural, retail, etc) § Multi-use Zoning: Allows retail and high density residential development to coexist in the same area. o Smart Growth: Focuses on strategies to encourage development of sustainable healthy communities. • EPA basic principles of smart growth: 1) Mixed land uses within one area 2) A range of housing opportunities and price
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