ENV 2100 Environment ScienceStudy Guide for Exam 2, to be Given on Wednesday, 13 October 2010Chapters 4, 5, 6Chapter 4: From Chemistry to Energy to Life- Remember that 92 elements are natural. How many are essential for life? Which four are the most abundant elements in life forms? - Remember that atoms typically have equal numbers of protons, neutrons, and electrons. Which of these are energy particles? Which can vary between atoms of the same element, the atomic number or the atomic mass? Thus, which subatomic particle located within the nucleus can vary from between atoms of the same element? - Which atoms tend to react with other atoms, those having full outer shells, or those with vacancies in their outer shells? - Vocabulary (be familiar with a formal definition or explanation):element isotope (& radioisotope) hydrogen bondatom chemical bond cohesionproton molecule solventneutron compound soluteelectron ionic bond solutionnucleus ion acidityatomic number covalent bond acidatomic mass polar covalent bond base- Remember that atoms must either share or transfer electrons in order to form chemical bonds.- Table salt (NaCl) and methane (CH4) are both compounds. Additionally, methane isa molecule, but table salt is not. Why not?- The pH scale is used to measure acidity. What range of values is included in the pH scale? Which pH value is most acidic? Which is least acidic (or most alkaline)? Which pH value is neutral? At which pH value is the concentration of H+ in solution equal to the concentration of OH- in solution?- Remember that chemical reactions rearrange matter. - What elements must occur in organic compounds to be considered “organic”? If a compound is not organic, it must be inorganic-- Be familiar with the 4 classes of organic macromolecules (carbohydrates, proteins, lipids, and nucleic acids) and their importance to cells and living organisms.- What are the major differences in the cells of eukaryotic organisms and prokaryotic organisms?- What is energy?- Be familiar with the first and second laws of thermodynamics.- By what process do plants and algae make their own food?- You should know that cellular respiration breaks down glucose in order to release energy that powers the activities of your cells.- What is decomposition?Ch5: Evolution, Biodiversity, and Population Ecology- Be familiar with these terms:evolution allopatric speciation habitatnatural selection sympatric speciation habitat selectionadaptive trait extinction niche:mutation endemic species specialistartificial selection background extinctions generalistbiological diversity mass extinctions population size & distributionspecies biosphere population densitypopulation ecosystem immigration & emigration- Which two people are most credited with developing the theory of evolution. They concluded that natural selection is the process by which evolution operates. Remember, evolution is an ongoing process, giving rise to genetic changes in populations and to new species.- You should know that the sources of genetic and physical variation in a population may include 1) sexual reproduction, 2) mutations, and 3) genetic drift.- Which is more common among animals, allopatric or sympatric speciation?- You should know that five mass extinction events occurred in Earth’s history, and thesixth mass extinction is now in effect. What is the underlying cause for the sixth extinction? Which species are most vulnerable to extinctions? The answer includesspecies that are endemics, have small geographic ranges, and that have small population sizes. - What is meant by carrying capacity, and what forces are at work in nature that keep population sizes in check?- Distinguish between density-dependent factors and density-independent factors.Ch6: Species Interactions & Community Ecology- Species interactions help shape communities. Be familiar with the three major typesof biotic interactions: competition (- -), consumer-resource (+ -), and symbiosis. Which of these three types is basis for food webs? Symbiosis can be subdivided into three major types of interactions: parasitism (+ -), mutualism (+ +), commensalism (+ 0). What is meant by competitive exclusion? - Be familiar with trophic levels: producers, consumers, detritivores, and decomposers. In a pyramid of biomass and in a pyramid of energy, which trophic level (producers, 1o consumers, 2o consumers, etc.) typically is largest?- What is a keystone species? Be familiar with examples of keystone species given in your textbook. - Distinguish between primary and secondary succession and the types of disturbances that give rise to these successions. What is meant by a climax community?- Why do invasive species have such negative effects on their new ecosystems? (Think about the case study involving the zebra mussel.) - What is ecological