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How did the described volcanoes in Iceland and the Philippines change the environment to lesser or greater extents? 2.Name and describe the attributes of the two categories into which all organisms can be divided based on how they obtain nutrition. All organisms can be divided into autothrops, which produce their own food, and heterothrops, which need to get their food from somewhere else. 3.Name and describe the roles of the three main trophic categories that make up the biotic structure of every ecosystem.
Give examples of organisms from each category. The main trophic categories are producers (plants), consumers (animals), and decomposers (fungi). 4.Give four categories of consumers in an ecosystem and the role that each plays. Primary consumers (herbivores) feed directly on producers. Secondary consumers (carnivores) feed on primary consumers. Consumers that feed on both plants and animals are called omnivores.
Describe different members of the decomposition food web. Detritus is composed largely of cellulose because it consists mostly of dead leaves, the woody parts of plants, and animal fecal wastes.
Scavengers, such as vultures, help break down large pieces of organic matter. Detritus feeders, such as earth worms, eat partially decomposing organic matter. Chemical decomposers (fungi) break down dead material on the molecular scale. 6.Differentiate among the concepts of food chain, food web, and trophic levels. A food chain is the transfer of energy and material through a series of organisms as each one is fed up on by the next.
A food web is the combination of all the feeding relationships that exist in an ecosystem.
A trophic level is a feeding level defines with respect to the primary source of energy. 7.Relate the concept of the biomass pyramid to the fact that all heterotrophs depend on autotrophic production. The biomass pyramid describes how the biomass of each trophic level decreases as it goes from the first level to the second and so on. If plants are gone then herbivores are gone too, which means we’re going to be goners. 8.Describe how differences in climate cause Earth to be partitioned into major biomes.
Earth is partitioned into biomes because climate varies at different parts of the world. 9.What are three situations that might cause microclimates to develop within an ecosystem? Different temperature and moisture within a biome is the microclimate of that location. Soil type and topography may also contribute to the diversity found in a biome. Relative acidity or alkalinity may also have an overriding effect on a plant or animal community. 10.Identify and describe the biotic and the abiotic components of the biome of the region in which you live. 11.Define the terms ecological succession and climax ecosystem. How do disturbances allow for ecological succession? 12.What role may fire play in ecological succession, and how may fire be used in the management of certain ecosystems? Fire resets the successional clock in some ecosystems. It can be used to manage unwanted shrubs. 13.What is meant by ecosystem resilience? What can cause it to fail? How does this relate to environmental tipping points?
Ecosystem resilience is its ability to return to normal functioning after a disturbance. If forests are removed from a landscape by human intervention and the area is prevented from undergoing reforestation by overgrazing, the soil may erode, leaving a degraded state that carried out few of the original ecosystem’s functions. The tipping point is a situation that can move the ecosystem in one direction or another. 14.What is meant by the term stakeholder? How does ecosystem management involve stakeholders? Stakeholders are people who have an interest in or may be impacted by a given approach to environmental management, including government decision makers. The valuable goods and services of ecosystems are recognized, and through active involvement in monitoring and managements, all stakeholders are included as important elements in stewardship of the resources. 15.Succinctly describe ecosystem management.
Ecosystem management takes an integrated view of terrestrial and aquatic ecosystems, integrates ecological concepts at a variety of spatial scales, incorporates the perspectives of landscape ecology so that the range of possible landscapes in an ecosystem is recognized and preserved, and is an evolving paradigm incorporating the objective of ecological sustainability. 16.Can ecosystems be restored? What has to happen for that to work? Ecosystems can be restored by retaining and restoring the ecological sustainability of watersheds, forests, and rangelands for present and future generations. 17.How much of Earth’s primary productivity is used or preempted by humans?
Humans preempt bout 40% of the primary productivity of the biosphere either by consuming it directly, by interfering with its production or use, or by altering the species composition or physical processes. 18.Examine the key messages from the Millennium Ecosystem Assessment’s governing board, and evaluate how these points affect you now and will affect you and your children in the future. The message of the Millennium Ecosystem Assessment’s Governing Board is that human impacts on this resilient natural world are so unprecedented and extensive that we crossed the line into unsustainable consumption some time ago and are now depleting ecosystem capital stock instead of living off its sustainable goods and services.
Define biological wealth and apply the concept to the human use of that wealth. Biological wealth is the life-sustaining combination of commercial, scientific, and aesthetic values imparted to a region by its biota. Environmental income is often the safety net that sustains them during lean times and can enable them in good times to generate wealth to improve their well-being. 2. Compare instrumental value and intrinsic value as they relate to determining the worth of natural species. Where does Leopold’s idea of the land ethic fit into these two categories? A species has instrumental value if its existence or use benefits some other entity. Something has intrinsic value when it has value for its own sake and doesn’t have to be useful to us to possess value. Leopold believed that the right thing to do is preserve the integrity, stability, and beauty of the biotic community.
What are the four categories into which the human value of natural species can be divided? Give examples of each one. Human value of natural species can be divided into value as sources for food and raw materials; value of sources for medicine and pharmaceuticals; recreational, aesthetic, and scientific value; and value for their own sake. Wild genes, new food plants, woods, and banking genes are sources for food and raw materials. Sources for medicine include rosy periwinkle to treat childhood leukemia. The natural ecosystems provide recreation ranging from fishing to camping. Intrinsic value can be found in religion and land ethic.
What means are used to protect game species, and what are some problems emerging from the adaptations of many game species to the humanized environment? Reforming policies that often lead to declines biodiversity, addressing the needs of people who live adjacent to or in high-biodiversity or whose livelihood is derived from exploiting wild species, practicing conservation at the landscape level, and promoting more research on diversity. Problems emerging include pollution, exotic species, and overuse. 5. What is the Lacey Act, why was it needed, and how is it used to protect wild species? The Lacey Act was the first national act that gave protection to wildlife by forbidding interstate commerce in illegally killed animals.
It was needed because many species were near extinction. Under the act, the U.S. Fish and Wildlife Service can bring federal charges against anyone violating a number of wildlife laws 6. How does the Endangered Species Act preserve threatened and endangered species in the United States? Give some examples of how the act has been implemented. The Endangered Species Act creates a listing of endangered species and critical habitats, and then creates recovery plans designed to allow species to survive and thrive. 7. What is one example of an endangered species that has benefited from protection under the Endangered Species Act?
What is biodiversity? What do scientists need to know to calculate it for a habitat? Biodiversity is the diversity of living things found in the natural world. The concept usually refers to the different species but also includes ecosystems and the genetic diversity within a given species. To estimate the number of individuals belonging to one species in a habitat, the mark, release and recapture technique may be used: an initial sample of animals is taken; a record how many individuals were captured in this first sample, and mark them all in some way; the batch of animals are then released back into the natural habitat; a second sample is taken, usually the following day; and record how many individuals have been captured in the second sample, and how many of those were already marked from the previous capture, and then release the sample of animals back into the wild.
What do the letters in the acronym HIPPO stand for? What is an example of each? Habitat Destruction- conversion of natural areas to housing, fragmentation of habitat patches, removal of natural debris like dead trees, and birds flying into cell phone towers Invasive Species- accidental introduction of brown tree snake to Guam, deliberate introduction of saltcedar to the Southwest for erosion control Pollution- nutrients that travel down the Mississippi River have created a dead zone where oxygen completely disappears Population- overconsumption of natural resources by humans
Overexploitation- forests are overcut for firewood, grasslands are overgrazed, and game is overhunted 10. Give several examples of ways habitat change can either harm species or aid them. Warming ocean waters and pollution have killed coral. Coral provides food and shelter for sea life so with less coral there is less diversity of marine animals. Humans initiate habitat restoration projects all around the world in an effort to restore native habitat. This brings species back into areas where they might not have been able to survive before. It helps restore equilibrium and ensure species survival.
What are IUCN, CITES, and the Convention on Biological Diversity? How do their roles differ? The International Union for Conservation of Nature (IUCN) monitor the successes and failures our conservation effort and help coordinate scientists or policy makers around the globe. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international treaty conveying some protection to endangered and threatened species by restricting trade in those species or their products. The Convention on Biological Diversity called for various actions and cooperative steps between nations to protect the world’s biodiversity. 12. What are the Aichi Biodiversity Targets?
•At least halve and, where feasible, bring close to zero the rate of loss of natural habitats, including forests •Establish a conservation target of 17% of terrestrial and inland water areas and 10% of marine and coastal areas •Restore at least 15% of degraded areas through conservation and restoration activities •Make special efforts to reduce the pressures faced by coral reefs
How did individuals act to help scientists in the Caribbean Sea? 2. What are some goods and services provided by natural ecosystems? the food, fuel, wood, fibers, oils, alcohols, and the like derived from the natural world, on which the world economy and human well-being depend. 3. Compare the concept of ecosystem capital with that of natural resources. What do the two reveal about values? Ecosystem capital – the sum of goods and services provided by natural and managed ecosystems, both free of charge. —– Natural Resources: Features of natural ecosystems and species that are of economic value and that may be exploited.
Also, features of particular segments of ecosystems, such as air, water, soil, and minerals. 4. Compare and contrast the terms conservation and preservation. 5. Differentiate between consumptive use and productive use. Give examples of each. 6. What does maximum sustainable yield mean? What factors complicate its application? 7. What is the tragedy of the commons? Give an example of a common-pool resource, and describe ways of protecting such resources. 8. When are restoration efforts needed? Describe efforts under way to restore the Everglades.
– Increase in restoration activity in last 30 years – spurred on by federal and state programs – Intent: repair the damage to specific areas so that normal ecosystem functioning and productivity returns (important to understand that every case is different)
– Everglades Restoration
Expected to take 36 years, 11 billion dollars (50% to come from fed gov. and 50% from other sources) – managed by US Army Corps of Engineers
Hope to restore wetlands and natural water systems which have been reduced by ½ by human activity
Water shortages in winter leave to little for natural system, and in summer rainy season, too much water diverted to Everglades.
Water quality now degraded because of nutrients (especially phosphorus) from agricultural run off)
Broader program originally begun in 1996 (cost $15 billion) – plan for removing 240 miles of levees/canals, creating system of reservoirs/underground wells to capture water for release during dry season o Funding
Major step – 2008, US Sugar agreed to sell its land and facilities to Florida for $1.7 billion – planned sale scaled way back because of Florida’s financial uncertainties (result of recent national recession) – new proposal invest $530 million – Pending Restorations
Other large systems suffering from human abuse/ignorance and focus of restoration projects – California Bay Delta, Chesapeake Day, Platte River basin, Upper Mississippi River system o Mississippi delta (Hurricanes Katrina and Rita) – in need o Restoration under way in ecological gems – Galapagos Islands (Illinois River, Brazilian Atlantic Forest, Tampa Bay)
Describe some of the findings of the most recent FAO Global Forest Resources Assessments. What are the key elements of sustainable forest management? Major Findings of Assessed Forests
In 2005, world’s forest covers 3.95 billion hectares (9.8 billion acres) (30% total land area). Defines “forests: as lands where trees are dominant and produce canopy greater than 10%. 1.4 Billion hectares (3.5 billion acres) classified as “other wooded land/woodlands.” Defined where tree cover less than 10% and the trees (and/or shrubs) do not grow to height above 5 meters) Account for 50% of plant productivity
Deforestation continues, primarily in developing countries). Deforestation: Defined by the FAO as the removal of forest and replacement by another land use (thus logging doesn’t per se count as deforestation if the forests are allowed to regenerate). “The removal of forest and replacement by another land use”
Global Rate of Net Deforestation: Est. 7.3 Million hectares (18 million acres) per year (18% better than 1990s.). Most important forest product: wood for industrial use. Hal forest land designated for “production” (wood harvested for pulp, lumber, fuel wood) Est. 1.2 billion hectares (2.9 billion acres) (30% world forests) managed for production of products 13.5% forests legally established protected areas. An increase (China in particular has increased). Nov. 2001 Meeting of signers of Kyoto Protocol in Marrakech, Morocco – role of forests in climate change formally acknowledged(forests carbon stores, sources of carbon emissions, carbon sinks) Est. 45% carbon stored on land is in forest – reduction in forest areas number dropped
Insect pests, disease, invasive species, and fires affect global forests significantly. (Ex. US/Canada, mountain pine beetle killed +11 million acres of forest since 1990s). 7. Gov. spending on forestry is not replaces. Ave. Gov. spends $7.50 and collects about $4.50 per hectare. Spend less = receive less. “Generally spend more on forestry than they collect in revenue. About 80% forests publically owned 10. What is deforestation, and what factors are primarily responsible for deforestation of the tropics? 11. What is the global pattern of exploitation of fisheries? Compare the yield of the capture fisheries with that of aquaculture. 12. Compare the objectives of the original Magnuson Act with those of the 2006 Magnuson-Stevens Fishery Conservation and Management Reauthorization Act.
Magnuson Act of 1976: extended the individual countries boundary to 200 miles off the coast – allowing fisheries to be managed under the authority of individual nations). • Magnuson-Stevens Fishery Conservation and Management Reauthorization Act (Magnuson Act): An act passed in 1976 that extended the limits of jurisdiction over coastal waters and fisheries of the United States to 200 miles offshore. Reauthorized in 2006 as the Magnuson-Stevens Fishery….. Act.
With strong bipartisan support. (Structure of regional councils retained, but required to set catch limits below MSY and employ precautionary principles), requires councils to end overfishing within two years after a species is judged to be overfished (instead of 10 years), depleted fish stocks must be rebuilt and maintained at sustainable levels, steps must be taken to assess and minimize bycatch, limited access programs, clear accountability measures are required to ensure that the councils and scientists follow the mandates of new law 13. What is the current status of the large whales? Discuss the controversy over continued whaling by some countries. Whales (in open ocean and coastal waters) heavily depleted by overexploitation until late 1980s Once harvested for oil, now prized for meat (delicacy)
1974- International Whaling Commission (IWC – organization of nations with whaling interests) decided to regulate whaling on MSY principle When population dropped below yield, IWC put ban on hunting to let population recover. Right whale, bowhead whale, blue whale all low levels, immediately protected. IWC drastic action: Moratorium on the Harvesting of all Whales beginning in 1986 (never been lifted but some limited whaling continues) Main Threat Today: entanglement wit fishing gear, collisions with ships Data hard to get, but whale species seem to be recovering
Ethical Controversy: Wrong to kill/eat such large unique mammals – whaling nations counter that their culture eats whales (like other cultures eat cows/turkeys)
− Coral Reefs
Reef building coral animals in symbiotic relationship with zooxanthellae – only found in water shallower than 75 meters Zooxanthellae: Photosynthetic algae that live within the tissues of coral species and enable them to grow productively in warm, shallow coastal areas. Corals build/protect land of reefs, attract tourists, important source of food and trade for local people, biodiversity Coral Bleaching: a condition, usually brought on by excessively high temperatures, in hard corals where the coral animals expel their symbiotic algae and become white in appearance. – damaged est. 16% of refs during record-high sea surface temp. accompanying the 1997-1998 El Nino, some annual phenomenon (repeated bleaching weakens and eventu. Kills corals)
Ocean Acidification: An outcome of the rise in atmospheric carbon dioxide; as the oceans take up more and more of the CO2, the carbonate ion concentration is reduced, making it more difficult for coral animals to build their calcium carbonate skeletons. – cause enormous loss biodiversity and economic value Exploitation of reefs driven by trade in tropical fish for food and the pet trade (Locals sometimes use dynamite and cyanide to flush fish out – illegal practice) One Solution: foster effective sustainable management – community based Solution: Incorporate coral reefs in Marine Protected Areas (MPAs) − Mangroves
Unique ability to take root and grow in shallow marine, inland of coral reef Protect coasts from storm damage, erosion, form rich refuge/nursery for fish Threatened from coastal development, logging, shrimp aquaculture Massive removal of mangroves – destabilization of entire coastal areas (erosion, siltation of sea grasses and coral reefs, ruin of local fisheries) Developing nations once considered them useless swampland, now begin to recognize their natural services 15. Compare the different levels of protection versus use for the different categories of federal lands in the United States. −Wilderness (given greatest protection), 2.) National Parks and National Wildlife Refuges (next lower level of protection),
National Forests (lowest level) − March 2009 – Omnibus Public Lands Management Act signed into law by President Obama – protected an additional 2.1 million acres of wilderness, increased wild/scenic river system by 50%, established new national parks/monuments, provided new federal land system − US unique – 40% country’s land is publicly owned and managed excluding development − Wilderness: land that is undeveloped and wild; in the US, land that is protected by the Wilderness Act -Authorized by the Wilderness Act of 1964, provides for permanent protecting of these undeveloped and unexploited areas (permanent structures, roads, motor vehicles, other mechanized transport prohibited – timber harvest excluded). – Some livestock grazing/mineral development allowed where existed previously hiking/other similar activities allowed. – Areas in any of the federally owned lands can be designated as wilderness
– Bureau of Land Management, National Park Service, Forest Service, Fish and Wildlife Service – manage wilderness lands − National Parks: Lands and coastal areas of great scenic, ecological, or historical importance administered by the National Park Service, with the dual goals of protecting them and providing public access. – AND – National Wildlife Refuges: Administered by the U.S. Fish and Wildlife Service, these lands are maintained for the protection and enhancement of wildlife and for the provision of public access -Protect 84 million and 96 million acres
-Intent: Protect areas of science/unique ecological significance, important wildlife species, provide public access for recreation and other uses (dual goals often conflict) – Increasingly, Agencies/envir. Groups/private individuals working together to manage natural sites as part of larger ecosystems. (ex. Greater Yellowstone Coalition formed to conserve larger ecosystem that surrounds Yellowstone National Part – acts to restrain forces threatening ecosystem) -This approach important for continued maintenance of biodiversity, also help restrict development up to the boards of the parks and refuges
Forest Service’s management principle in 1950s and 60s – multiple use: allowed for a combination of extracting resources, using forest for recreation, protecting watersheds and wildlife • Intent to achieve balance among these uses, actually emphasized the extractive uses (justify exploitation of public lands by private interest groups). 17. How do land trusts work, and what roles do they play in preserving natural lands? avoid this by using firewood harvested locally or, if you need to carry firewood a distance, by finding wood marked with a U.S. Department of Agriculture (USDA) tag confirming that the logs are safe to move. A nonprofit organization that will accept either outright gifts of land or easements—arrangements in which the landowner gives up development rights into the future but retains ownership of the parcel. The land trust may also purchase land to protect it from development.
The land trust movement is growing considerably: There were 429 land trusts in the United States in 1980 and more than 1,723 in 2010, as reported by the Land Trust Alliance, an umbrella organization in Washington, DC, serving local and regional trusts. These trusts protect almost 47 million acres of land. The Nature Conservancy, a national and international land trust, also protects 102 million acres in other countries. Land trusts are proving to be a vital link in the preservation of ecosystems. In 1999, alarmed about signs of development in their region, 30 residents of Grand Lake Stream in northeastern Maine (pop. 150) met to share their concerns. Out of that meeting grew the Downeast Lakes Land Trust, which, over time, has carried out a $30 million conservation effort that has protected 342,000 acres of woodlands, 60 lakes, and 1,500 miles of riverfront.
In what ways is human population ecology similar to and different from that of other organisms? Why is it difficult to determine a carrying capacity for humans? We resemble growth rates of r-strategists (exponential, J shaped curve) but we also have high levels of parental care and late (and slow) reproductive rates (like history of a slower growing equilibria species with the growth of r strategist). Definition of ‘human population’ is different than most populations of organisms (not confined to a small area – due to tech). Unique in our ability to regulate our reproduction, use fite, store our food, change our habitats to suit our needs. How has the global human population changed from prehistoric times to 1800? From 1800 to the present? What is projected over the next 50 years?
Neolithic Revolution: The development of agriculture begun by human societies around 12,000 years ago, leading to more permanent settlement and population increases • Specialization of labor, trade with other settlements/commerce, greater storage of food/preservation, – reduced mortality rate, expanding agriculture
Industrial Revolution: During the 19th century, the development of manufacturing processes using fossil fuels and based on applications of scientific knowledge. Costs: pollution, exploitation
Medical Revolution: Medical advances and public sanitation led to spectacular reductions in mortality, beginning in the late 1800s and extending to the present. Diseases such as smallpox, diphtheria, measles, scarlet fever – black plague/cholera (epidemics) Louis Pasteur and others – found diseases caused by pathogens • Vaccinations, treating sewage/water, 1930s discovered penicillin, nutrition
Green Revolution: The development and introduction of new varieties of (mainly) wheat and rice that have increased yields per acre dramatically in many countries since the 1960s. Pesticide ance: the ineffectiveness of a pesticide when the target organisms are no longer affected by it Resistance: the development of more hardy pests through the effects of the repeated use of pesticides in selecting against sensitive individuals in a pest population Cost: increased erosion, soil and water pollution, loss of native plant varieties, pesticide resistance
Environmental Revolution: In the view of some, a coming change in the adaptation of humans to the rising deterioration of the environment. The Environmental Revolution should bring about sustainable interactions with the environment. Hopefully come through technology
2010 average GNI per capita less than $1,005 (average $510) • Includes E. W. Central Africa, India, countries of S. Asia, few former Soviet republics – Developed Countries: The high-income industrialized countries – US, Canada, western European nations, Japan, Korea, Australia, New Zealand, as well as many middle income countries such as Latin America, China, eastern Europe, many Arab states. – Developing Countries: Countries in which the gross domestic product is less than $936 per capita. Includes nations of Africa, India, other countries of southern Asia, and some former Soviet republics. 4.What three factors are multiplied to give total environmental impact? Are developed nations exempt from environmental impact? Why or why not? – IPAT formula: A conceptual formula, proposed by ecologist Paul Ehrlich and physicist John Holdren, relating environmental impact (I) to population (P), affluence (A) and technology (T) [I = PAT] – IPAT fits well with carrying capacity
Prior to Industrial revolution, humans survived through subsistence agriculture (small, isolated relatively stable populations, this system was basically sustainable) – After WWII, modern medicines introduces (death rates plummeted, population boom) – What happens when farms become too small to support the next generation… VVV – Land Ownership Reform
Effect of affluence – it enables the wealthy to clean up their immediate environment by transferring their wastes to more distant locations and allows them to obtain resources from more distant location. Also provides people with opportunities to exercise lifestyles choices consistent with concerns fro stewardship/sustainability. – World’s wealthiest 20% are responsible for 76% of natural good consumption 7.What information is given by a population profile?
Longevity: The max. life span of individuals of a given species. The known record for humans is 122 years. – Population Profile: A bar graph that shows the number of individuals at each age or in each five-year age group, starting with the youngest ages at the bottom of the profile. (shows the age structure) – Age Structure: Within a population, the different proportions of people who are old, middle aged, young adults, and children. – Each bar in Age Structure represents one cohort (group of the same age) of the population 8.How do the population profiles and fertility rates of developed countries differ from those of developing countries? -Population Projections for Developed Countries
Graying: The increasing average age in populations in developed countries and in many developing countries that is occurring because of decreasing birthrates and increasing longevity. Example: Italy, Japan
Natural Increase: The number of births minus the number of deaths in a given population. The natural increase does not take into account immigration and emigration and is the percent of growth (or decline) of a given population during a year. It is found by subtracting the crude death rate from the crude birthrate and changing the result to a percent. Solution: allow more immigration (but implications to art, culture, religion) Many developed countries
Fertility rate rise in late 1980s and projected stabilize between 290 million and 300 million – Population Projections for Developing Countries
Fertility rates generally declining, but still well above replacement level Average TFR (Total Fertility Rate) (excluding China) is currently 3.2 Populations profiles of developing countries have a pyramidal shape.
Burkina Faso: lowest income countries, big increase, high fertility rate Indonesia – population growth rate lower than Burkina Faso, large population may stabilize earlier, but it has a lot of population momentum Highly developed countries facing problems of graying population High fertility rates in developing countries maintain exceedingly young population 9.Compare future population projections, and their possible consequences, for developed and developing countries.
If a country like Burkina Faso is to maintain current standard of living – amount of housing and all other facilities (and food production) must be almost doubled in as little as 25 years – jobs must be available for large number of young people (population growth can cancel out efforts to get ahead economically Enormous Growth for developing world
Discuss the immigration issues pertaining to developed and developing countries. Which countries are sending the most immigrants and which are receiving the most?
Perception poorer countries believe they can improve well being by moving to wealthier country – need more and younger workers (should welcome) Problems with immigration: prejudice, want higher birthrates instead of more immigrants)
Migration from poor/middle country to poor/middle country
Leads to refugee camps (with diseases and hunger), easy targets for exploitation (parents paid for children to work).
Urbanization (in 2008 more than half population lived in cities) Poor countries sending, rich countries/neighboring middle countries recieving 11.What is meant by population momentum, and what is its cause? Population momentum: A property whereby a rapidly growing human population may be expected to grow for 50-60 years after replacement fertility (2.1 live births per female) is reached. Momentum is sustained because of increasing numbers entering reproductive age.
In a young population (like Burkina Faso), momentum is positive (small portion in upper age groups and many young people entering their reproductive years) In a population (like Europe) momentum is negative (low fertility, shrink population 12.Define the crude birthrate (CBR) and the crude death rate (CDR). Describe how these rates are used to calculate the percent rate of growth and the doubling time of a population. Crude Birthrate (CBR): the number of births per 1,000 individuals per year. • Crude Death Rate (DFR): the number of deaths per 1,000 individuals per year.
CBR – CDR = Natural increase/decrease on population/1000/year
(Natural increase/decrease on population/1000/year) / 10 = percent increase (or decrease) in population per year. 13.What is meant by the demographic transition? Relate the epidemiologic transition and the fertility transition (two elements of the demographic transition) to its four phases. Epidemiologic Transition
Most of human history – CDR high. Middle of 19th century – death rates declined. Now most mortality due to degenerative diseases and many people survive to old age. This pattern of change in mortality rates is the Epidemiologic Transition (and element of demographic transition) Epidemiology: study of diseases in human societies
In now-developed countries birthrates declined – fertility transition Fertility transition did not happen at same time as the epidemiologic transition. Time when these 2 patters are out of phase is time of rapid population growth (like during the 19th and early 20th centuries, and during baby boom years) – Phases of the Demographic Transition
Demographic transition usually presented in occurring in 4 phase Phase I: Primitive stability from a high CBR being offset by an equally high CDR Phase II: Declining CDR (epidemiologic transition), CBR remains high Phase III: CBR declines (declining fertility rate), population still growing Phase IV: modern stability (low CFR to low CBR)
Developed countries generally completed demographic transitions. Developing countries are still in Phase II and III (still growing rapidly) 14.What are examples of countries in different stages of the demographic transition? No one is in Phase 1, but developing countries can be in phase II or III, while developed nations are on Phase IV.
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