1 Environmental Science Study Guide for Exam 3 --- Chapters 6 (Part 2), 7, 8, 11 To be Given on Monday, 8 November 2010 Ch6: Species Interactions and Community Ecology (Part 2) (From part 1 of this chapter, be familiar with the National Invasive Species Act of 1996 and with ecological restoration) This portion of the chapter deals with biomes of the world. Be familiar with a formal definition for biome. For each biome, be familiar with its general climatic conditions (e.g., wet and moderate temperatures for the temperate rainforest biome) and its general locality (e.g., temperate rainforest occurs on the Pacific Northwest). temperate deciduous forest tropical rainforest tundra temperate grasslands savanna boreal forest (taiga) temperate rainforest desert Ch7: Environmental Systems & Ecosystem Ecology What is a system? Systems are sometimes affected by negative feedback loops and positive feedback loops, both of which are based on outputs from the system. Which one (negative or positive feedback) stabilizes the system? Which one drives the system to one extreme? Which one is common in nature, and which is rare in nature? What is the underlying cause for the large dead zone at the mouth of the Mississippi River, where it meets the Gulf of Mexico? The answer has to do with eutrophication. What does this term mean? What is the source of eutrophication for the Mississippi River, and how does this affect aquatic life, ultimately causing oxygen depletion? Vocabulary (be familiar with these terms) primary production net primary production biogeochemical cycles cellular respiration nutrients Nutrient cycles: carbon cycle You should know that photosynthesis, respiration, and decomposition are natural processes that affect the carbon cycle. What is the world’s largest reservoir (pool) of carbon? What is the world’s second largest pool of carbon? This second pool, unlike the first, is directly accessible to living organisms. In what two ways are humans increasing the amount of atmospheric carbon dioxide (CO2)? phosphorus cycle Phosphorus is naturally most abundant in the rocks and is released and made available to living organisms via weathering. How have people affected the phosphorus cycle? Have we generally caused the amount of phosphorus to increase or decrease, and what are some sources of phosphorus that might be added to the environment via human activities?2 nitrogen cycle What is the largest reservoir for nitrogen on Earth? Nitrogen gas can not be used by plants or animals. By what process do certain bacteria convert nitrogen gas (N2) to a form that can be readily used by plants? (Give me the term for the process.) On the whole, have people increased or decreased the amount of available nitrogen in the environment, and which activities have had this effect? The Harmful Algal Bloom and Hypoxia Research and Control Act (1998) called for monitoring and assessment of the dead zone in the Gulf of Mexico. What are the solutions for reducing and ameliorating both eutrophication and the size of the dead zone? Ch8: Human Population The human population is growing exponentially and at the faster rate than anytime in history. In addition to technology, what other factors have contributed to the rapid rate of population growth over the last 250 years? Why did China implement a one-child policy in 1970? What were two of the unintended outcomes of the policy in regard to the demography of the Chinese population? What does the term demography mean? Developing nations have the greatest rate of population growth, and some slowing of growth rates, on Earth, is occurring. Do absolute numbers of people continue to increase or decrease? Similarly, do falling growth rates mean fewer people? Population growth rates depend on birthrates and __________ rates. Immigration and emigration also affect the rates. How do the attitudes of policymakers run contrary to the environmental and societal effects of human population growth? Is growth correlated with poverty or wealth? Be familiar with the conceptual model I=PATS. What do the symbols represent? Which nation of the world has both the largest per capita and total ecological footprint? Which nation is ranked second in regard to total ecological footprint? A population’s age structure (distribution of the population among different age groups) affects its growth rate. When the age structure of a population takes on a “rocket” shape, is the population growing or declining, and is there much reproduction taking place? Answer the same question in regard to an age structure that is “top heavy”, in which more of the population is concentrated in older age groups. Human populations are not distributed uniformly across the planet. Instead the greatest concentrations (densities) of people are in the most fertile areas of the planet. In addition to access to birth control, urbanization and education of women lead to reduced birthrates. Why is this true? Where in the world is the AIDS epidemic having its greatest effect on human populations? Are populations still climbing in this region? Ch11: Biodiversity and Conservation Biology The term biodiversity encompasses several levels of diversity (species, genetic, and ecosystem). The term species diversity encompasses both species richness and evenness. What do these terms mean? What formal term is given to biologists who discovery, identify, name, and classify organisms? In terms of environmental change, why are populations that have much genetic variation better off than populations with less variation? What is meant by inbreeding depression?3 Why do some groups (taxa) have far more species than do other groups? What is clearly the most species rich group (taxon) on Earth? Only about 2 million of the world’s 10 to 100 million species have been described by scientists. Why is it difficult to identify species? Biodiversity is not uniformly distributed on Earth. Where does the greatest biodiversity occur? What is meant by the background rate of extinction and, using this rate, how many species of mammals and marine species should be going extinct annually. Five major extinction spasms have occurred in the distant past. Which one caused the greatest devastation to the existing biodiversity (95% of marine species went extinct)? According to scientists, the world is now in the midst of a sixth major