Exam 3 Review- Environmental Science
What requirements does an industrial and technological society have if it wishes to continue its economic growth?
Inexpensive energy. A direct link exists between economic growth and the availability of inexpensive energy. Most industrial societies want to ensure a continuous supply of affordable energy. The higher the price of energy, the more expensive goods and services become.
What is the difference between deforestation and desertification? What causes each?
- Deforestation is the permanent removal of trees to make room for something besides forest. This can include clearing the land for agriculture or grazing, or using the timber for fuel, construction or manufacturing. Natural causes: hurricanes, fires, parasites and floods Human activities: agricultural expansion, cattle breeding, timber extraction, mining, oil extraction, dam construction and infrastructure development. - Desertification is the process of converting arid and semiarid land to desert because of improper use by humans. It's caused by overgrazing, unsuccessful farming practices, and removal of vegetation for fuelwood
What is the difference between low-level radioactive waste and high-level radioactive waste?
- Low-level waste consists of industrial items (such as mops, rags, cloths, paper towels, clothing and floor sweepings) that have become contaminated with low levels of radioactivity during routine cleanup and maintenance activities at nuclear generating stations. Low-level waste contains mostly short-lived radioactivity and can be handled safely with simple precautions. - High-level waste is the used nuclear fuel. When used fuel bundles are removed from the reactor, they are highly radioactive, contain long-lived radioactivity and generate significant heat. High-level waste requires careful management over the very long term.
What is radioactivity? What types of radiation are produced by nuclear reactions?
- Radioactivity is the emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei. - Nuclear disintegration releases energy from the nucleus as radiation, of which there are three major types: 1. Alpha radiation: consists of a moving particle composed of two neutrons and two protons. Alpha radiation usually travels through air for less than a meter and can be stopped by a sheet of paper or the outer, nonliving layer of the skin. 2. Beta radiation: consists of moving electrons released from nuclei. Beta particles travel more rapidly than alpha particles and will travel through air for a couple of meters. They are stopped by a layer of clothing, glass, or aluminum 3. Gamma radiation: a type of electromagnetic radiation that does not consist of particles. Other forms of electromagnetic radiation are X rays, light, and radio waves. Gamma radiation can pass through your body, several centimeters of lead, or nearly a meter of concrete.
What are species diversity, genetic diversity, and ecosystem diversity? What influences these? Give examples.
- Species diversity: a measure of the number of different species present in an area. Some localities naturally have high species diversity, while others have low species diversity Ex: the presence of four or five different species of tree in a woodland forest - Genetic diversity: a term used to describe the number of different kinds of genes present in a population or a species. Several things influence the genetic diversity of a population: 1. Mutations 2. Migration 3. Sexual Reproduction 4. Population size 5. Selective breeding Ex: mutations occurred in the DNA of certain insect species that made some individuals tolerant to the insecticide DDT, even though the chemical had not yet been invented. These mutant characteristics remained very rare in these insect populations until DDT was used. Then, this characteristic became very valuable to the insects that carried it. Because insects that lacked the ability to tolerate DDT died when they came in contact with DDT, more of the DDT-tolerant individuals were left to reproduce the species, and therefore, the DDT tolerance became much more common in these populations. The evolution of DDT resistance is similar to the evolution of resistance in human antibiotic medication - Ecosystem diversity: a measure of the number of kinds of ecosystems present in an area. Many regions of the world appear to be quite uniform in terms of the kinds of ecosystems present. For example, large parts of central Australia, North Africa, and southwestern United States and adjacent Mexico are deserts. While there are general similarities (low rainfall, thorny woody plants, and animals that can survive on little water), each of these deserts is different and has specific organisms typical to the region.
What are the major threats to biodiversity? List and explain at least 3.
- The causes of biodiversity loss are complex and interconnected. The Convention on Biological Diversity names five key drivers of biodiversity loss: 1. habitat loss 2. overexploitation 3. introduction of exotic species 4. predator and pest control activities 5. climate change. • Habitat loss: when human activities result in the conversion of natural ecosystems to human-dominated systems. • Overexploitation: occurs when humans harvest organisms faster than the organisms are able to reproduce. • Introduction of exotic species: second greatest threat to native biodiversity and can be harmful to human health. Exotic diseases are on the rise because of increased transportation and encroachment of humans into previously remote ecosystems.
How has the development of the automobile altered our lifestyle and energy usage?
- The growth of the automobile industry, first in the United States and then in other industrialized countries, led to roadway construction, which required energy. Thus, the energy costs of driving a car were greater than just the fuel consumed in travel. As roads improved, higher speeds were possible. Bigger and faster cars required more fuel and even better roads. - The car also changed people's lifestyles. Vacationers could travel greater distances. New resorts and chains of motels, restaurants, and other businesses developed to serve the motoring public, creating thousands of new jobs. Because people could live farther from work, they began to move to the suburbs. - As people moved to the suburbs, they also changed their buying habits. Labor-saving, energy-consuming devices became essential in the home. The vacuum cleaner, dishwasher, garbage disposal, and automatic garage door opener are only a few of the ways human power has been replaced with electrical power.
What are the advantages and disadvantages of the two methods of mining coal. Include in your discussion some of the pollution issues.
- There are two methods of extracting coal: surface mining and underground mining. 1. Surface mining (strip mining) involves removing the material located on top of a vein of coal, called overburden, to get at the coal beneath Advantages: - Cheaper - capable of extracting more amount of resources. - safer than underground mining Disadvantages: - disrupts the landscape, as the topsoil and overburden are moved to access the coal - Mountaintop removal - Can only be used if the overburden is less than 100 meters - valleys have streams that drain them, and the soil and rock that are pushed into the valley contaminate the water. 2. Underground mining: If the overburden is thick, surface mining becomes too expensive, and the coal is extracted through underground mining - The deeply buried coal seam can be reached in two ways. In flat country where the vein of coal lies buried beneath a thick overburden, the coal is reached by a vertical shaft. In hilly areas where the coal seam often comes to the surface along the side of a hill, the coal is reached from a drift-mine opening. Advantages: - Doesn't disrupt the surface environment as much as surface mining Disadvantages: - subsidence (sinking of the land) occurs if the mine collapses. General: Advantages: - Reliable - Affordable - Abundance Disadvantages: - Many miners suffer from black lung disease, a respiratory condition that results from the accumulation of fine coal-dust particles in the miners' lungs - Acid mine drainage: occurs when the combined action of oxygen, water, and certain bacteria causes the sulfur in coal to form sulfuric acid. Sulfuric acid can seep out of a vein of coal even before the coal is mined. Streams may become so acidic that they can support only certain species of bacteria and algae. - Air pollution: Dust is generated by mining and transportation of coal. The large amounts of coal dust released into the atmosphere at the loading and unloading sites can cause local air pollution problems. - Air pollution from coal burning releases millions of metric tons of material into the atmosphere and is responsible for millions of dollars of damage to the environment. - Carbon dioxide and climate change are other problems associated with the burning of coal.
What are some services provided to the environment by biodiversity?
1. Nutrient Cycling: Carbon, nitrogen, phosphorus, and many other chemical elements are cycled through ecosystems by a complex array of bacteria and other organisms. 2. Cultural Uses: Enjoyment of landscapes and individual organisms, scientific study and other educational activities, and the spiritual significance of specific places and things are all examples of cultural uses of ecosystems. 3. Water Regulation and Supply: Intact soil and vegetation slow the flow of water and allow water to penetrate the soil and recharge aquifers. These processes make water available for agricultural, industrial, and domestic uses. 4. Disturbance Regulation and Erosion Control: Colonization of disturbed sites—caused by fires, floods, windstorms, landslides, or human actions—by plants and animals heals the scars and prevents continued damage. Furthermore, intact ecosystems provide flood and erosion control. Mangrove forests, marshes, and other wetlands protect shorelands from erosion. The network of roots in forested areas and grasslands ties the soil together and protects watersheds 5. Waste Treatment: Decomposer organisms recycle both natural and human-produced organic wastes. Excess nutrients are removed by organisms and pollutants are removed from air, soil, and water and converted to less harmful materials. 6. Food and Raw Materials: In many parts of the world, people are involved in a subsistence economy and rely directly on ecosystems for food and raw materials. They harvest wild plants and animals as food and medicine and use plants to provide food for livestock, building materials, and firewood. 7. Atmospheric and Climate Services: Many atmospheric gases are cycled between organisms and the atmosphere. The removal of carbon dioxide during photosynthesis is important in controlling the warming of the planet. Many countries have planted trees to help remove carbon dioxide from the air as a response to concerns about climate change. 8. Recreation: Natural areas provide important recreational opportunities for an increasingly urban population. Camping, hiking, kayaking, fishing, hunting, bird-watching, photography, ecotourism, and sight-seeing provide exercise and enjoyment. 9. Biological Control Services: All organisms are involved in a complex set of interrelationships with other kinds of organisms. Some relationships are harmful. These harmful organisms are labeled pests. But every pest also has organisms that cause it harm—dragonflies, swallows, and bats eat mosquitoes that carry disease and are annoying; ladybird beetles eat aphids; and cats are often kept to control rodent populations on farms 10. Pollination Services: Many different kinds of insects are pollinators that are extremely important to the successful fruiting of plants. The careless elimination of these beneficial insects by the broad use of insecticides can negatively affect agricultural production. 11. Habitat/Refuges: Refuges and other protected areas provide places that protect species of concern, serve as nursery sites for specific species, or provide temporary stopping places for migratory species 12. Genetic Resources: If we cause the extinction of a potentially useful organism, we have lost the opportunity to use it for our own ends. Most of the wild ancestors of our most important food grains, such as maize (corn), wheat, and rice, are thought to be extinct. Over 50 percent of the most common drugs used to control and cure disease are derived from plants and animals, and new ones are discovered each year. 13. Soil Formation: The weathering of rock provides new mineral material for the building of soil. Bacteria, fungi, tiny animals, and the roots of plants are involved in building soil by breaking down organic matter, incorporating it into the mineral part of the soil, and creating a loose texture to the soil
What is a nuclear chain reaction?
A nuclear chain reaction occurs when the neutrons released from a splitting nucleus strike the nuclei of other atoms causing those atoms to split. This results in more neutrons being released which causes other atoms to split, thus causing a chain reaction
Describe the human energy pyramid.
A pyramid of energy represents how much energy, initially from the sun, is retained or stored in the form of new biomass at each trophic level in an ecosystem. Typically, about 10% of the energy is transferred from one trophic level to the next, thus preventing a large number of trophic levels. • People in less-developed countries generally feed at lower trophic levels than those in the developed world. • They tend to eat plants themselves instead of feeding the plants to animals and eating the animals. • A lack of protein in the diet can lead to malnutrition. • Many people in more-developed countries buy their food and suffer from over-nutrition. • 66% of North Americans are overweight, and 33% are obese
Distinguish between a resource and a reserve. What determines if a resource is a reserve?
A resource is a naturally occurring substance of use to humans that can potentially be extracted. Reserves are known deposits from which materials can be extracted profitably with existing technology under prevailing economic conditions.
Why is nuclear fusion not a practical form of energy at the present time?
Because they produce plutonium-239, which can be used to produce nuclear weapons, which is a politically sensitive topic. Most countries have discontinued their breeder reactor programs following accidents or political decisions. The United Kingdom, Germany, the United States, and France have breeder reactors that are currently not in operation. Russia and China currently have a total of three operating breeder reactors, and India is currently building a new breeder reactor.
How do the concepts of birthrate and population growth differ?
Birthrate is defined as the number of individuals born into a population, whereas population growth is the result of birthrate and immigration minus death rate and emigration, or the total net increase in the population size.
How do the environmental impacts of mining and use of coal for energy compare to that of crude oil?
Coal: 1. Landscape disturbance: 2. Acid mine drainage: 3. Air pollution Crude Oil: 1. Oil spills 2. Sites of oil drilling 3. Air pollution
What effect does conservation have on energy consumption? List some ways.
Conservation is not a way of generating electricity, but a way of reducing need for additional energy production / consumption and saving money for the consumer. There is typically a relationship between the cost of an item and its energy efficiency. Often, poorly designed, energy-inefficient buildings and machines can be produced inexpensively. - The short-term cost (purchase price) is low, but the long-term cost for upkeep and energy utilization is high. Typically, the cost of more efficient buildings or machines is higher, but the difference in initial price is made up by savings in energy cost over several years. The following are examples of government actions designed to improve energy efficiency: 1. Imposition of improved fuel economy standards for new automobiles and trucks. 2. Tax incentives for those who upgrade insulation, windows, doors, heating and cooling systems, and other appliances. 3. Phaseout in 2014 of most uses of incandescent lightbulbs, which are very inefficient. The development of fluorescent and LED bulbs to replace them quickly followed. 4. Established higher energy efficiency standards for appliances. 5. Investment in more efficient electricity distribution. 6. Improvement in high-speed rail transportation
What are the differences between density-dependent limiting factors and density-independent limiting factors?
Density dependent: are those that become more effective as the density of the population increases. Ex: the larger a population becomes, the more likely it is that predators will have a chance to catch some of the individuals. Density independent: are population-controlling influences that are not related to the density of the population. Ex: a sudden rainstorm may drown many small plant seedlings and soil organisms.
What are the issues concerning the use of coal?
Environmental impacts of the use of coal: • Landscape disturbance- Surface mining disrupts the landscape, as the topsoil and overburden are moved to access the coal. • Acid mine drainage- Since coal is a fossil fuel formed from plant remains, it contains sulfur, which was present in the proteins of the original plants. • Air pollution Dust- is generated by mining and transportation of coal. The large amounts of coal dust released into the atmosphere at the loading and unloading sites can cause local air pollution problems
What is extinction and what organisms are most in danger of becoming extinct?
Extinction is the death of a species or the elimination of all the individual's of a particular kind. Natural extinction can occur in areas where there is a low population density, a smaller habitat area, a specialized niche, and low reproductive rates. Human accelerated extinctions occur when humans become the dominant organism. Organisms prone to Extinction: - Low population density - Found in small area - Specialized niche - Low reproductive rates
What are the steps in the nuclear fuel cycle? What is the common risk?
Follows the process from the mining of uranium to the disposal of the waste from power plants. 1) Mining and milling 2) Enrichment 3) Fuel fabrication 4) Use of the fuel 5) Reprocessing or storage 6) Transportation Most of the concerns about the use of nuclear fuels relate to the danger associated with the radiation produced by the fuel and the waste products of its use. 1. Biological Effects of Ionizing Radiation 2. Radiation Protection 3. Reactor Safety 4. Terrorism 5. Nuclear Waste Disposal 6. Decommissioning Nuclear Power Plants
What are the principle sources of energy used to generate electricity?
Fossil fuels (coal, natural gas, and petroleum), nuclear energy, hydroelectric plants, and other renewable energy resources (geothermal, wind, solar, biomass, or waste)
What are fossil fuels and how do they form? How do they differ in their formation?
Fossil fuels are the modified remains of plants, animals, and microorganisms that lived millions of years ago. Coal, oil, and natural gas. - Coal formed during the Carboniferous period, 299 million to 359 million years ago, when the Earth's climate was warm and humid. There were extensive swamps with forests of primitive land plants. These conditions were conducive to the accumulation of large amounts of plant material that was converted into deposits of coal by heat and pressure. - Oil and natural gas formed primarily from tiny marine organisms whose bodies accumulated in large quantities on the seafloor and became compressed over millions of years. Heat and pressure from overlying sediment layers eventually converted the organic matter into oil and gas.
How does the complexity of a society relate to its energy usage?
Greater complexity = greater energy use. - Energy use in different countries varies Uses of energy range from residential, commercial, industrial, and transportation. Developed (Industrialized) countries use energy for all uses roughly equally. Less-developed countries use more energy for residential use - cooking, heating. Developing countries use more energy for industrial use.
Explain the statement that the sun is the ultimate source of energy as pertaining to fossil fuels.
In every ecosystem, the sun provides essential energy. Initial energy transfer occurs through photosynthesis. - light energy is converted to chemical energy, then passes on up the food chain/web. Fossil fuels were formed hundreds of millions of years ago. They result from the accumulation of energy-rich organic molecules produced by organisms as a result of photosynthesis over millions of years. We can think of fossil fuels as concentrated, stored solar energy. Countries that are developing new industries dedicate a high percentage of their energy use to them.
What changes might be anticipated if world population were to double in the next 35 years?
It will put a greater demand on resources. Some countries have abundant natural resources, such as good agricultural land, energy resources, or mineral resources. Others are resource poor. Thus, some countries can sustain high populations while others cannot. Overall, the ecological frootprint will more than likely sky rocket if our population doubles. We'll use more technology for our day-to-day lives.
How do r-strategists and K-strategists differ?
K-strategists usually occupy relatively stable environments ant tend to be large organisms that have relatively long lives, produce few offspring, and provide care for their offspring. r-strategists - are typically small organisms that have a short live, produce many offspring, exploit unstable environments, and do not reach a carrying capacity.
What limits the use of tidal power as a source of electricity?
Limited to areas that have greater tidal ranges. Tidal changes of roughly 5 meters (16 feet) are needed to produce practical amounts of power, suitable sites are limited - estuaries in France, Canada, Russia, China. S. Korea is building a larger facility.
Contrast the various renewable energy sources - pros and cons.
Major Kinds of Renewable Energy 1. Biomass Conversion Pros: - Multiple ways to get biomass: fuel wood, Municipal and industrial Solid wastes, Agricultural crop residues and animal wastes, and "Energy" plantations - Reduces landfill volume, costs of fuel (when it makes economic sense to burn trash) - energy plantations (biomass): reduces air pollution and improves engine efficiencies in newer model cars --> can be used as a "flex-fuel" - E85 - saves hydrocarbon fuels. Cons: - Due to intense population growth, an estimated 1.3 billion people cannot get enough fuel wood, and are using it faster than rate of regeneration. - It is a source of greenhouse gases, air pollution and particulate matter (soot / smoke). • Releases 75 organic compounds, 22 of which are known carcinogens • Source of CO2 in atmosphere. - It is inefficient - most energy lost as waste heat - Use leads to deforestation and desertification. - Requires large volume and dependable supply, and must be sorted. - Produces air pollution, including pollutants not found in other forms of biomass - dioxins from plastics - With crop residues and animal waste: Issues include low energy/weight ratio, soil erosion and depletion of organic matter in agricultural areas, air pollution, and can be economically unsound. - Energy plantations(Biomass):• Additionally, ethical considerations: • of converting food crops to energy crops, driving up costs of that product. • removing it from the world "food bank" • Government subsidies are required, because energy available from biofuels is less than that of equal amount of hydrocarbon fuel (gasoline). - Habitat and biodiversity loss - Most of the forests have been destroyed in Asia and Africa - Deforestation. - Desertification has increased in these regions. - Air pollution --> Burning wood produces air pollution - nitrogen and sulfur oxides, volatile organic compounds ; Smoke, particulates, carbon monoxide, and hydrocarbons contribute to health issues. - Conversion of land from growing food crops to biomass fuel crops is controversial when many go hungry. - Burning of crop residue and animal waste removes a source of nutrient renewal for subsistence farmers. 2. Hydroelectric Power Pros: - no release of atmospheric pollutants once construction is completed. - technically possible to triple the electricity produced by hydropower with current technology. Cons: - Dependent on geography/topography - The potential for developing hydroelectric power is limited to mountainous regions and large river valleys. - Reservoir construction causes significant environmental and social damage. - Community relocation - Three Gorges Dam in China has displaced over 1 million people and flooded recognized heritage and scenic areas. - Loss of farmland or forest land due to flooding - Prevention of fish migrations - Trapping of silt fills in reservoir and stops flow of nutrients downstream to provide nutrients to floodplains and farms. - Toxic material (e.g.)Mercury and Arsenic) accumulation - leaches from rocks that lie beneath the dam and collects in tissues of fish. 3. Solar Energy: Pros: - Daily energy from the sun is 600x greater than energy produced each day by all other energy sources combined. - Utilized in 3 ways: Passive, active, and electrical - They are silent, produce no emissions, and use no fuel other than sunlight Cons: - Main Problem - Solar energy is intermittent and diffuse - need sunny days. And many places are unsuitable due to climate. - PV cells and technology are still expensive - Parabolic mirrors require very large amounts of land to position mirrors or collectors, destroying habitats. - Large areas of mirrors result in large amounts of reflected sunlight, heating up the air space above - with implications on any organisms that are caught there: Federal wildlife studies indicate up to 28,000 bird deaths annually due to incineration as birds get caught in reflected sunlight. Birds are attracted to insects that are also attracted to the light. 4. Wind Energy Pros: - Clean fuel source - Doesn't rely on combustion like fossil fuels - newer windmills have slower-moving and shorter rotors that many birds find easier to avoid. Cons: - Some areas are better suited than others, and winds are variable. - Wind energy must be coupled with other sources of energy. - Some areas which have the highest wind availability are too far from sources to transport it. - The moving blades produce noise and some consider the windmills visual pollution. - Moving blades are hazardous to migrating birds - Vibrations from generators can cause irritation and potentially structural damage. 5. Geothermal Energy Pros: - The United States produces about 30 percent of the world's geothermally generated electricity. - Able to use pumps to obtain geothermal energy from areas that are not geologically active. Cons: - Steam released in the process often contains H2S gas (rotten egg smell). - Minerals carried in hot water or steam carry ions and metals in solution, which get deposited as corrosion on pipes and equipment, and are toxic to fish when that waste water is discharged into local bodies of water 6. Tidal Power Pros: - Minimal environmental impacts Cons: - Limited to areas that have greater tidal ranges. - But do affect migrations of sea creatures.
** Contrast the usage of energy for electricity generation and transportation in other Developed countries around the world (such as Europe and Japan) to the United States. What role do government regulations and tax policies play in that usage?
Most countries that have extensive bus and rail systems also have high fuel taxes - encourages use of public transportation. In North America, government policies have kept energy costs artificially low to support the automobile and tire industry while removing support for bus and rail transport. Private automobiles in North America (5 % of world population) consume over 40% of world gasoline production. Industrialized nations have 20% of the world's population, but use 55% of the world's electricity. Per capita use in North America is 9 1⁄2 times greater than that in less-developed countries. Many developed countries use only 60% of that used in the U.S. - Japan, Germany, France, Netherlands. Governments can manipulate prices of energy with tax policy and subsidies. Energy consumption behavior of most people is motivated by economics rather than a desire to wisely use energy resources.
Where does nuclear energy come from?
Nuclear energy comes from uranium, a nonrenewable resource that must be mined. Worldwide, energy from nuclear power plants is the fifth most important energy source after coal, oil, natural gas, and hydroelectric power.
What are some problems associated with overexploitation of aquatic environments?
Overexploitation occurs when humans harvest organisms faster than the organisms can reproduce. Overexploitation has driven some organisms to extinction and threatens many others. - Changes in the types of fish being caught- The commercial fishing industry has been trying to market fish species that previously were regarded as unacceptable to the consumer. - Aquaculture: Fish farming. Nutrient overloads from concentrations of fish can pollute local bodies of water - The escape of exotic species may harm native species. They may breed and create a new species - freshwater aquaculture involves the conversion of land to a new use. Often the lands involved are mangrove swamps or other wetlands that many people feel should be protected
Why do people who live in less-developed/ overpopulated countries use plants as their main source of food?
People who live in overpopulated countries use plants as their main source of food because they cannot afford the 90-percent energy loss that occurs when plants are fed to animals. The same amount of grain can support ten times more people at the herbivore level than at the carnivore level.
What is pollution? Can all hazardous substances in an environment be classified as pollution?
Pollution is the introduction of contaminants into the natural environment that cause adverse change. No. It's considered a pollutant if it has the potential to threaten the surrounding natural environment
How does the population growth curve of humans compare with that of short-lived organisms?
Population growth of bacteria growing in a petri dish begins with a lag phase, continues through an exponential growth, and then levels off due to an accumulation of toxic waste. Human population growth has a long lag phase followed by a sharply rising exponential growth phase that is still rapidly increasing.
How does the U.S. differ in its treatment of radioactive spent fuel rods from other countries?
The US has 99 operating nuclear power plants, about 22% of the world total Reprocessing or storage are the two options available for spent fuel rods. Reprocessing: U-235 and plutonium are separated from the spent fuel and used to manufacture new fuel rods. Less than half of the world's fuel rods are reprocessed. At present, India, Japan, Russia, France, and the United Kingdom operate reprocessing plants as an alternative to storing rods as waste. The U.S. stores them.
List 4 factors that could determine the carrying capacity of an animal species.
The availability of raw materials, availability of energy, accumulation of waste products, and interactions among organisms
What are the problems associated with the use of solid waste/biomass as a source of energy?
The negative environmental impacts, which are loss of habitat, air pollution, release of carbon dioxide, and decrease in food production (see above for more info)
What are the limitations in the use of hydroelectric power?
The potential for developing hydroelectric power is limited to mountainous regions and large river valleys. Dependent on geography/topography Hydroelectric power - created using flowing water to create electricity - conversion of potential energy to electric energy. Damming a river and storing water in a reservoir is the most common method.
How have nuclear accidents affected nuclear policy and the construction of new nuclear power plants?
Three accidents generated concern about nuclear power plant safety: Three Mile Island in 1979, Chernobyl in 1986, and Fukushima Dai-ichi in 2011. BUT--> The continuous safe operation of the most current plants, new designs that have passive safety systems, and the demand for a form of energy that does not release carbon dioxide has altered thinking by many governments. It appears that some older plants may be shut down but that those currently being built will be completed.
What factors affect the degree of damage to living tissue by exposure to radiation?
Time, distance, and shielding. 1. Time is important because the longer one is exposed to a source of radiation, the more radiation is absorbed. 2. Distance is important because the farther a person is from the source, the less likely that person will be hit by radiation. In addition, alpha and beta radiation will only travel a short distance through air. 3. Shielding is important because it can stop radiation and prevent a person from being exposed. Because gamma radiation can travel many meters through air and can penetrate the body, shielding is very important. Water, lead, and concrete are common materials used for shielding from gamma radiation.
Why is the impact of humans on ecosystems greater today than at any time in the past?
Today the human impact on the environment is greater because the population is greater than ever before, and technology is now more advanced and harmful towards the environment.
Compare and contrast the generation of electricity from fossil fuel and nuclear power plants?
• Electricity from fossil fuels: Fossil fuel power plants burn coal or oil to create heat which is in turn used to generate steam to drive turbines which generate electricity However, burning carbon-based fuels produces large amounts of carbon dioxide, which drives climate change. • Electricity from nuclear power plants: In the production of electricity, a nuclear reactor serves the same function as burning a fossil fuel. It produces heat, which converts water to steam to operate a turbine that generates electricity. After passing through the turbine, the steam must be cooled, and the water is returned to the reactor to be heated again. Various types of reactors have been constructed to furnish heat for the production of steam. They differ in the moderator used, in how the reactor core is cooled, and in how the heat from the core is used to generate steam. The three most common kinds of nuclear reactors are boiling-water reactors, pressurized-water reactors, and heavy-water reactors.
**How are crude oil and natural gas formed? What are the important requirements in the formation of a deposit of oil or gas in order for it to become a potential reserve?
• Formation of oil: Products from the past. - They probably originated from microscopic marine organisms. - When these organisms died and accumulated on the ocean bottom and were buried by sediments, their breakdown released oil droplets - Gradually, the muddy sediment formed rock called shale, which contained dispersed oil droplets. Although shale is common and contains a great deal of oil, extraction from shale is difficult because the oil is not concentrated. - In recent years, the application of hydraulic fracturing technology has greatly increased the amount of oil and natural gas that can be obtained from shale. - in instances where a layer of porous sandstone formed on top of the oil-containing shale and an impermeable layer of rock formed on top of the sandstone, concentrations of oil often form. Usually, the trapped oil does not exist as a liquid mass but rather as a concentration of oil within sandstone pores, where it accumulates because water and gas pressure force it out of the shale. These accumulations of oil are more likely to occur if the rock layers were folded by geological forces. • Formation of Natural Gas: products from the past. - Natural gas, like oil, forms from fossil remains- If the heat generated within the Earth reached high enough temperatures, natural gas could have formed along with or instead of oil. This would have happened as the organic material changed to lighter, more volatile (easily evaporated) hydrocarbons than those found in oil. - The most common hydrocarbon in natural gas is methane (CH4). - The conditions that led to the formation of oil and gas deposits were not evenly distributed throughout the world. - The Middle East has nearly 50 percent of the world's oil reserves
What are the main causes of biodiversity loss?
• Habitat loss: when human activities result in the conversion of natural ecosystems to human-dominated systems. • Overexploitation: occurs when humans harvest organisms faster than the organisms are able to reproduce. • Introduction of exotic species: second greatest threat to native biodiversity and can be harmful to human health. Exotic diseases are on the rise because of increased transportation and encroachment of humans into previously remote ecosystems.
What are some actions that can be taken to prevent extinction?
• Legislations to protect species that are in danger of becoming extinct. • The preservation of the habitat required by endangered species • Education of the local population about the need to protect endangered species.