Environmental Science 1305 Study Guide Test 1
Environmental Science 1305 Study Guide Test 1 Env 1301
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This 12 page Study Guide was uploaded by Hannah Fretheim on Saturday September 24, 2016. The Study Guide belongs to Env 1301 at Baylor University taught by Trey Brown in Fall 2016. Since its upload, it has received 94 views.
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Date Created: 09/24/16
Environmental Science 1305 Test 1 Study Guide Environmental Science- studies how humans and their environments interact with each other and attempts to minimize the negative effects of humans on their environments - An organism’s environment includes the physical, chemical and biological things that impact it and is made up of both biotic (living) and abiotic (nonliving) things. What is Science? Science and Pseudoscience: - Science: o Scientists do not seek to prove or disprove anything. Instead, data gathered from experiments is said to support or not support a hypothesis. o Science only deals with things in the natural world which can be measured and tested. o It is important to acknowledge our own bias and try to be as objective as possible. o Experiments must be repeated and conducted by more than one scientist. o Scientists must be willing to self-correct by updating or changing their theories in response to new evidence. o Data should be gathered and organized in a way that other people can understand and use. - Pseudoscience- may claim to be scientific but is not o Elements of pseudoscience include psychobabble, emphasis on personal anecdotes, extraordinary claims, unfalsifiable claims, lack of connection to other research, lack of peer review and lack of self-correction. The Scientific Method: - Observation- Includes gathering and recording information about the natural world, can be quantitative or qualitative - Hypothesis- a proposed explanation to a research question which is often based on observations and tested through experimentation - Experimentation- controlled testing of hypotheses, usually contains independent and dependent variables as well as a control group o Laboratory vs. field experiments - Models- representations of phenomena which are hard to study until they are put on a scale that is easier to understand and work with Theory- an explanation of things occurring in nature that has been repeatedly supported by scientific studies, a hypothesis can become a theory once it has been repeatedly supported Scientific uncertainty will always exist to an extent, but it can be reduced as more studies are done and more evidence is found Ethics in Environmental Science Ethics in Research: - Data must be reported as accurately as possible and should never be falsified (alter outcome of results), fabricated (results are made up), or plagiarized - Peer review- before they are published, studies are reviewed by other scientists in the field to ensure that the studies were done well and honestly - Objectivity- it is important to eliminate bias and conflicts of interest as much as possible Environmental Ethics: - Deals with moral issues related to the human-environmental interaction - 3 perspectives of environmental ethics: anthropocentric, biocentric and ecocentric Environmental Justice- Seeks to equally involve all people in environmental decision-making, focuses on reducing inequality for disadvantaged groups of people - Toxic waste dump in Warren County, North Carolina Human Use of Resources: Ecological Footprint- the effect of the human population on its environment - Calculated by 6 factors: carbon, cropland, grazing land, forest, built-up land and fishing grounds - Our ecological footprint requires more land and resources than the earth has available for us Renewable resources can replace themselves quickly and are (at least theoretically) unlimited if used carefully. Nonrenewable resources cannot replace themselves fast enough and are therefore limited Sustainability- using resources in a way that will preserve them for people of all generations Environmentalism is a movement that uses education and political action to protect the environment Conservation includes preserving and restoring species and ecosystems as well as finding efficient ways to use resources Preservation ethic- seeks to preserve ecosystems in the state they are currently in, supported by John Muir Conservation ethic- states that resources should be used in the most efficient way they can be so as to benefit as many people as possible, supported by Gifford Pinchot Others concerned with human-environment relationship: - Plato and Aristotle in Ancient Greece and Mencius in ancient China - Benjamin Franklin, George Perkins Marsh and Theodore Roosevelt in America - Thomas Malthus predicted that the environment would eventually run out of resources to serve the human population. - Rachel Carson- warned people about the use of pesticides, particularly DDT, because of the harm done to wildlife and potentially to humans, Silent Spring Matter and Energy Matter Makes up both ecosystems and economic systems. Matter is made up of atoms. Atoms combine to form molecules. - An element is made up of one type of atom - 99% of the mass of all organisms is composed of carbon (C), hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P) and sulfur (S). - A compound is a molecule made up atoms of different elements in a fixed ratio - i.e. Methane includes carbon and hydrogen. When it reacts with oxygen, carbon dioxide (CO2) and water (H2O) are produced. Matter is conserved (not created or destroyed)- biogeochemical cycle (for non-living things) Energy describes how much work is able to be done - Work- how much force is applied to an object X how much the object moves in the direction of that force - Types of energy: potential energy (no work is currently being done), chemical energy, kinetic energy, gravitational potential energy, thermal energy (heat), radiant energy (the sun) First law of Thermodynamics- when energy moves from one form to another, the total amount of energy stays the same, also called “conservation” of energy Second law of Thermodynamics- Although the amount of total energy stays the same during energy transformations, there is an increase in the amount of energy that can do. - i.e. When the kinetic energy of a wind turbine is transformed into electrical energy, some of the energy becomes unusable heat energy. Entropy- how much disorder exists in a system, will increase over time without input of energy (according to the second law of thermodynamics) Food Webs Trophic levels: - primary producers (autotrophs)- produce food for other organisms in the food web through photosynthesis o gross primary production- the total amount of food produced by primary producers o net primary production- the amount of production available to other organisms after the primary producer has used what it needs from the gross primary production - consumers (heterotrophs)- cannot make their own food and must get energy from eating other organisms o can include primary, secondary and tertiary consumers o herbivores, carnivores and omnivores - detritivores/ decomposers- feed off of dead organisms Photosynthesis- takes in carbon dioxide, water and light energy and releases oxygen and glucose Cellular respiration- takes in glucose and oxygen and releases carbon dioxide, water and energy Energy is lost at each trophic level, meaning there is more energy at the bottom among primary producers and the least amount of energy at the top among tertiary consumers (forms an energy pyramid) Ecosystems and Economic Systems Ecosystem- includes the organisms which live in a certain place, the environment they live in and the way that organisms interact with each other and their environment Economics- a social science that studies the flow of goods and services as well as economic systems - The study of ecosystems which are mostly made up of humans falls under the branch of economics. - i.e. The Maasai people joined with other people groups in their area to form an economic system (which is made up of people, institutions and commercial interests) based on trading goods. Sustainable Development- developing in a way that provides for the needs of people and their economies, while keeping the environment in good shape for people of future generations Economic Systems Subsistence vs. market vs. centrally planned economy - subsistence- people or communities mostly support themselves - market- more reliant on buying and selling but decisions are made by individuals or businesses rather than a single authority - centrally planned- decisions about the economy are made by the central authority Property ownership: - property can be state owned, privately owned, owned by a community (common property) or it can be open access which is open to anyone Economic systems are not closed, meaning they do not function only within themselves but rely on things outside the economic system such as the environment. It is important to acknowledge the ways that economic systems and the environment affect each other. - Economic externalities How are economic systems like food webs? - Goods are produced through manufacturing and then consumed by buyers - Energy is lost throughout the process Interaction of Ecology and Economics “Tragedy of the Commons”- deals with the problem that if property or resources are open to everyone and not regulated, they will be abused and ruined - open access property and common-pool resources - i.e. Chesapeake Bay and the Cuyahoga river (“Burn On”) Threats to Ecosystems: - Habitat destruction is the biggest threat - Deforestation, overharvesting, introducing non-native species and pollution are also threats Our economy is based on growth and relies on resources found in the environment. Our economy cannot grow and unlimited amount and at some point, we will run out of resources. How do we deal with the threat that economic systems are to the environment? Elinor Ostrom’s suggestions for managing the commons: 1. Make clear who has access and what the boundaries are 2. How much of the resource one can use should be based on how much they put into sustaining it 3. The resource pool should be monitored command-and-control regulations- laws which control what people can and cannot do with penalties being given if laws are disobeyed Pigovian taxes- instead of punishing people, place taxes on economic externalities in order to pay for them Environmental economics and ecological economics- study the effects of economics on the environment Market-based approach- Allowing and encouraging more resources to be privately owned and purchased by people may actually help conserve these resources Evolution Evolution- “Any change in heritable traits within a population across generations.” - Evidence suggests that all life on earth shares a common ancestor. Examples of evolution impacting the environment: - Fish population evolved to be smaller when people were only catching big fish - HIV- different strains were found, may have come from a strain found in chimps - Grasslands becoming deserts due to a reduction of the species’ which fertilize them Common descent- The idea that all life on earth is related through a common ancestor. Descent with modification- Parents pass traits to their children, but children are different from their parents and from their siblings. Natural Selection: - It is based on the idea that creatures with certain beneficial traits will survive and pass those traits on to their offspring while those who do not have the beneficial traits will die off. - Natural Selection gave credibility to the theory of evolution because it provided a natural mechanism for it. - Wallace and Darwin How Evolution Works - More offspring are produced than needed and all these different offspring have somewhat different traits from their parents and each other o Recombination- DNA of two parents is combined o Mutation- DNA changes slightly, making offspring different from parents - The offspring with more beneficial traits survive and pass on their traits while those with less beneficial traits die. Evidence Evidence that led to the idea of Natural Selection: - Artificial selection- humans can breed animals to have certain traits o domestication of animals throughout history - Galapagos tortoises- Tortoises on different islands were similar, but were different enough to be considered separate species. The differences between the species corresponded with what was beneficial to life on the specific island that each species lived on. Evidence used for Evolution: - Comparative anatomy - Embryology - Fossil record - DNA comparisons - i.e. Whales- evidence from these four categories supports the idea that whales descended from a four-legged ancestor. Darwin and the Galapagos Finches: - One species of finches spread across multiple islands. Those with beaks that were unique, had less competition for food and survived while others died off. - Eventually, the finches on each island became so different from those on other islands that they were no longer the same species. - The differences between the species of finches were specific to the individual islands that each lived on. Biodiversity DNA - Molecules which are blueprints for all the traits that we possess - 46 strands of DNA (chromosomes) located in the nucleus of every one of our cells - DNA => RNA (partial copies of a part of DNA) => protein (built in ribosomes, must be the correct shape to work) => growth - Made up of 4 nucleotides (A, T, C and G). A and T pair together and C and G pair together. - Gene- A piece of DNA which codes for a trait o organisms share similarities in their genetic makeups Importance of Genetic Diversity Genetic diversity- accumulation of all of the genes and gene combinations found within a population or between different populations made up of the same species - Creatures are considered to be of the same species if they can reproduce with each other offspring which can also reproduce - A population includes the members of a species who are in the same place at the same time The more genetic variations exist among members of a species, the more likely there is to be individuals who can survive in spite of challenges or changes to their environment. - i.e. fish populations which survive heat wave More biodiversity leads to more possible food paths in food webs. - Aquatic ecosystems have more diversity than desert and tundra ecosystems and therefore more food paths. Population Distribution and Change Distributions: - Limited distributions- species only lives in a few, small place on earth o Species with limited distributions are more likely to become extinct o i.e. mountain gorilla, bay checkerspot butterfly - Wide ranging distributions- spread all across the world o i.e. house sparrow- lives on all continents except Antarctica - Some populations are shrinking or expanding in distribution o Bay checkerspot butterfly has a shrinking distribution while the house sparrow’s distribution is growing Population density: - Population density- amount of a species concentrated in a specified area (such as number per km )2 - Abundance of a species- size of the population Population Growth: - J-shaped population growth – population grows exponentially o Most common when a population is less dense, lives in a good climate and has available resources - S-shaped population growth- population growth levels off o Happens when space and resources run out o Carrying capacity (K)- how large the population can grow without running out of resources - Factors that limit population growth o Density dependent factors- affected by the density of the population, i.e. disease o Density independent factors- density of population does not matter i.e. floods Life Histories: - K-selected species o Tend to live longer and reproduce later o Have fewer offspring but spend more time nurturing them o Population growth of these species tends to be near their carrying capacity - r-selected species o reproduce lots of offspring but are more likely to die (especially due to environmental disturbances) o their population sizes change regularly Species Interactions Mutualism- a relationship in which two organisms benefit each other Niche- includes a creature’s habitat, trophic level and environmental needs Competition: - occurs when species rely on the same resources - intraspecific competition- within a species - interspecific competition- between different species - competitive exclusion principle- if two species compete for a resource which is limited and their niches are the same, one species will beat out the other o This usually leads to different niches among animals living in the same place o Resource partitioning- species who live in the same place use different resources Threats to biodiversity Mass extinction- large amounts of species become extinct in an unusually short amount of time - There are enough species currently going extinct for it to be considered a time of mass extinction - Extinction is a normal part of nature, however, majority of the species currently going extinct are the result of humans o Anthropocene ear- human-dominated time period Habitat destruction: - As humans expand and build, many habitats are destroyed or reduced greatly, causing population decreases - This is the biggest human threat to biodiversity Invasive Species: - When species that are originally from somewhere else are introduced to a new environment, they may threaten the native species there - Invasive species may kill other species through predation or disease, or they may compete with them for resources Other threats: - Illegal trafficking and trading is also killing off many endangered species. - Predators such as wolves are sometimes threatened due to their being killed to protect livestock. - Pesticides have been shown to threaten creatures other than pests, such as the peregrine falcon Protection of Endangered Species: Endangered Species Act of 1973 - Legally protected both endangered species and threatened species - Included plants and invertebrates - Kept critical habitats from being destroyed CITES - Convention of International Trade in Endangered Species of Wild Fauna and Flora - Deals with international trading of wildlife - Almost 180 nations have signed it Lacey Act - Helps enforce CITES - Illegally harvested species cannot be traded, even if they were harvested outside of the U.S. Conservation and the Economy: - Restoring species such as the American Gray Wolf can be difficult because they threaten the economic interests of ranchers. - However, conserving species can also benefit the economy through ecotourism Ecosystem Diversity Species diversity- number of different species that live in a community and how much there is of each of them Species richness- how many different species live in a community Biomes: - Geographical areas with specific groups of organisms and certain growth forms of vegetation - Terrestrial Biomes o Tropical forest, temperate forest, temperate grassland, desert, tropical savanna, Mediterranean scrub, taiga or boreal forest, tundra o Different climates and soil in different terrestrial biomes - Aquatic biomes o Streams & rivers, lakes & ponds, open ocean, ocean floor, coral reefs & kelp forest, mangrove forests, salt marshes, freshwater wetlands o Lower biodiversity Biodiversity hotspots - supports high numbers of species and has lost 70% of its area - each is home to at least 1500 species of plants that are not found anywhere else - they cover a small amount of land but support a large number of the earth’s species Islands- equilibrium model of biogeography- while the number of species on an island stays the same, the kinds of species on the island changes, extinction and immigration balance each other out Species special to an Ecosystem - Keystone species- important species whose loss greatly harms an ecosystem o i.e. gray wolves - Foundation species- species whose bodies effect the physical structure of their communities o i.e. trees which form a canopy - Ecosystem engineers- have an influence on the structure of their ecosystems o i.e. beavers - indicator species- reflect the conditions of their ecosystems - umbrella species- when these species are protected, the ecosystem as a whole is protected - flagship species- species that get humans interested in protecting their ecosystems Succession- when an environmental disturbance happens, new species colonize the area and the community eventually changes - primary and secondary succession - pioneer community- first to develop, usually made up of species that can live in difficult conditions - climax community- final community that will exist until another disturbance starts the process of succession over again Speciation- forming of new species - allopatric speciation (geographic)- members of the original species were separated by a geographical barrier - sympatric speciation- no geographical barrier Threats to Ecosystem Diversity There are parts of ecosystems which are beneficial to us (ecosystem services) and many of these are under threat Habitat Fragmentation - divides ecosystems and decreases biodiversity - edge effects- the environment at the edge of habitat fragments is different from the rest of it Invasive Species - Some invasive species increase the risk of fire and pollution - Invasive species also impact the economy and were expected to have cost us $1.4 trillion in 2010 Solutions: - Convention on Biological Diversity- agreement between 168 countries to protect the earth’s ecosystems and their biodiversity o Protected areas- linked by habitat corridors To ensure that an area is protected, it is important to keep in mind things like keystone species, invasive species and disturbances. Can work with local communities to create buffer zones to avoid overdeveloping the land around a protected area o Marine protected areas- protected area in oceans or on the coast that are important to biodiversity - Non-governmental organizations o The Nature Conservatory- the Forever Costa Rica project Debt-for- nature swaps were used to work with developing countries to help the environment Human Populations Population Growth Population Density - Immigration and births grow the population while emigration and deaths cause it to decrease - Coasts and river valleys tend to have the highest population densities, while deserts and arctic tundra tend to have the lowest. - Over half of the world’s population is concentrated in cities The human population is growing much faster than it did for most of history - The industrial revolution in the 1800s led to a large amount of population growth - The population has gone from 2 billion in 1927 to 7 billion in 2012 - The population is predicted to grow to 9 billion by 2042 - It is predicted that although we will continue to grow exponentially for some time, we will eventually stabilize - The rate of growth actually reached its height in the 60s and is lower now, but still high Age Structure - Fertility rate- average number of children a woman in the population has o Replacement-level fertility- fertility rate needed to keep a population at its current number - Developed countries tend to have lower fertility rates than developing countries - When populations have a decreasing fertility rate, they end up with a large elderly population and fewer people to support them Human Development Index - Based on health, economic development and education - Divides countries into “developed” and “developing” - Developed countries have a much greater ecological footprint than developing countries - The world is actually doing better when it comes to development than we typically think o Example of infant mortality rate in Sub-Saharan Africa- may not look at first like it is getting better, but rate is expected to decrease greatly over time, some countries in this region are farther along than others High fertility rates in developing countries - Many newborns die in these countries and many women face health risks and potential death during childbirth - 200 million women in developing countries are infected with STDs which are among the most curable - Better access to contraceptives would help to both stabilize these populations and improve women’s health - Better education for women usually corresponds with more reproductive health services and a more stable population - Providing contraceptives would actually save money in the long run because fewer children would have to be provided for Problems with Overpopulation: “Soylent Green” clip- overpopulation led to lack of resources, fighting, unrest, poor education, sanitation issues, pollution and environmental damage Technology has given us the ability to reduce limiting factors and raise our carrying capacity, but we will reach our carrying capacity at some point - Better hygiene and germ theory improved health, our habitat expanded through things like air conditioning and transportation of food Space- limiting factor, more people means more conflict when it comes to using space Attempts to deal with overpopulation: - India- reduced fertility rate and decreased infant mortality, encouraged citizens to make informed decisions regarding childbearing - China- one-child family policy reduced population growth but fell below replacement-level fertility o Problems- not enough young adults to support the elderly, men outnumber women significantly - Education and empowerment of women- has been linked to better population control Challenge we are faced with: How Can We Achieve High Development While Sustaining Resource Use?
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