NRC Science Education Standards

Project 2061 Benchmarks

(www.npa.edu)

Content Standard: Unifying Concepts & Processes (pp. 115-119)

Fundamental concepts that underlie Systems, Order, and Organization include:

• A system is an organized group of related objects or components that form a whole. Systems can coexist, for example, of organisms, machines, fundamental particles, galaxies, ideas, numbers, transportation, and education.
• Systems have boundaries, components, resources flow (input and output), and feedback.
• Think and analyze in terms of systems.
• The idea of simple systems encompasses subsystems as well as identifying the structure and function of systems, feedback and equilibrium, and the distinction between open and closed systems.
• An understanding of regularities in systems, and by extension, the universe; they then can develop understanding of basic laws, theories, and models that explain the world.
• An assumption of order establishes the basis for cause-effect relationship and predictable.
• The behavior of units of matter, objects, organisms, or events in the universe-can be described statistically.
• Types of organization provide useful ways of thinking about the world include the periodic table of elements and the classification of living things
• Living systems also have different levels of organization-for example, cells, tissues, organs, organisms, populations, and communities.

Fundamental concepts that underlie Constancy, Change, and Measurement include:

• Interactions within and among systems result in change.
• Changes vary in rate, scale, and pattern, including trends and cycles.
• Energy can be transferred and matter can be changed.
• Changes in systems can be quantified.
• Evidence for interactions and subsequent change and the formulation of scientific explanations are often clarified through quantitative distinctions-measurement.
• Mathematics is essential for accurately measuring change.
• Different systems of measurement are used for different purposes.
• An important part of measurement is knowing when to use which system.
• Scale includes understanding that different characteristics, properties, or relationships within a system might change as its dimensions are increased or decreased.
• Rate involves comparing one measured quantity with another measured quantity.

Fundamental concepts that underlie Evidence, Models, and Explanation include:

• Evidence consists of observations and data on which to base scientific explanations.
• Using evidence to understand interactions allows individuals to predict changes in natural and designed systems.
• Models are tentative schemes or structures that correspond to real objects, events, or classes of events, and that have explanatory power.
• Models help scientists and engineers understand how things work.
• Models take many forms, including physical objects, plans, mental constructs, mathematical equations, and computer simulations.
• Scientific explanations incorporate existing scientific knowledge and new evidence from observations, experiments, or models into internally consistent, logical statements.
• Different terms, such as "hypothesis," "model," "law," "principle," "theory," and "paradigm" are used to describe various types of scientific explanations.

Fundamental concepts that underlie Evolution and Equilibrium include:

• Evolution is a series of changes, some gradual and some sporadic, that accounts for the present form and function of objects, organisms, and natural and designed systems.
• The general idea of evolution is that the present arises from materials and forms of the past.
• Equilibrium is a physical state in which forces and changes occur in opposite and off-setting directions
• Steady state, balance, and homeostasis also describe equilibrium states. Interacting units of matter tend toward equilibrium states in which the energy is distributed as randomly and uniformly as possible.

Content Standard A: Science as Inquiry (pp. 173-176)

Fundamental abilities and concepts that underlie the Abilities Necessary To Do Scientific Inquiry include:

• Identify questions and concepts that guide scientific investigations.
• Use technology and mathematics to improve investigations and communications.
• Formulate and revise scientific explanations and models using logic and evidence.
• Recognize and analyze alternative explanations and models
• Communicate and defend a scientific argument.

Fundamental concepts that underlie the Understandings about Scientific Inquiry include:

• Scientists conduct investigations for a wide variety of reasons:
  • to discover new aspects of the natural world,
  • to explain recently observed phenomena,
  • to test the conclusions of prior investigations or the predictions of current theories.
• Scientists rely on technology to enhance the gathering and manipulation of data.
• New techniques and tools provide new evidence to guide inquiry and new methods to gather data, thereby contributing to the advance of science.
• Mathematics is essential in scientific inquiry. Mathematical tools and models guide and improve the posing of questions, gathering data, constructing explanations and communicating results.
• Scientific explanations must adhere to criteria such as:
  • a proposed explanation must be logically consistent;
  • it must abide by the rules of evidence; it must be open to questions and possible modification;
  • and it must be based on historical and current scientific knowledge.
• Results of scientific inquiry-new knowledge and methods-emerge from different types of investigations and public communication among scientists.
• In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge.
• The methods and procedures that scientists used to obtain evidence must be clearly reported to enhance opportunities for further investigation.

Content Standard B: Physical Science (pp. 176-181)

Fundamental concepts that underlie Conservation of Energy and the Increase in Disorder include:

• The total energy of the universe is constant.
• Energy can be transferred by collisions in chemical and nuclear reactions, by lightwaves and other radiations, and in many other ways.
• Energy can never be destroyed. As these transfers occur, the matter involved becomes steadily less ordered.
• All energy can be considered to be either kinetic energy, which is the energy of motion; potential energy, which depends on relative position; or energy contained by a field, such as electromagnetic waves.
• Everything tends to become less organized and less orderly over time. Thus, in all energy transfers, the overall effect is that the energy is spread out uniformly when we burn fuels.

Content Standard D: Earth & Space Science (pp. 187 & 190)

Fundamental concepts that underlie Energy in the Earth System include:

• The sun is the major external source of energy.
• Heating of earth's surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents.
• Global climate is determined by energy transfer from the sun at and near the earth's surface. This energy transfer is influenced by dynamic processes such as cloud cover and the earth's rotation, and static conditions such as the position of mountain ranges and oceans.

Content Standard C: Life Science (pp. 181 & 187)

Fundamental concepts that underlie the Molecular Basis of Heredity include (Rift Valley Fever):

• In all organisms, the instructions for specifying the characteristics of the organism are carried in DNA, a large polymer formed from subunits of four kinds (A, G, C, and T).
• The chemical and structural properties of DNA explain how the genetic information that underlies heredity is both encoded in genes (as a string of molecular "letters") and replicated (by a templating mechanism). Each DNA molecule in a cell forms a single chromosome.
• Transmission of genetic information to offspring occurs through egg and sperm cells that contain only one representative from each chromosome pair. An egg and a sperm unite to form a new individual.
• Changes in DNA (mutations) occur spontaneously at low rates. Some of these changes make no difference to the organ ism, whereas others can change cells and organisms. Only mutations in germ cells can create the variation that changes an organism's offspring.

Fundamental concepts that underlie the Biological Evolution include:

• Species evolve over time. Evolution is the consequence of the interactions of:
  • the potential for a species to increase its numbers,
  • the genetic variability of offspring due to mutation and recombination of genes,
  • a finite supply of the resources required for life, and
  • the ensuing selection by the environment of those offspring better able to survive and leave offspring.
• Natural selection and its evolutionary consequences provide a scientific explanation for the fossil record of ancient life forms, as well as for the striking mol ecular similarities observed among the diverse species of living organisms.
• The millions of different species of plants, animals, and microorganisms that live on earth today are related by descent from common ancestors.

Fundamental concepts that underlie the Matter, Energy, & Organization in Living Systems include:

• All matter tends toward more disorganized states.
• Living systems require a continuous input of energy to maintain their chemical and physical organizations. With death, and the cessation of energy input, living systems rapidly disintegrate.
• The energy for life primarily derives from the sun. Plants capture energy by absorbing light and using it to form strong (covalent) chemical bonds between the atoms of carbon-containing (organic) molecules. These molecules can be used to assemble larger molecules with biological activity (including proteins, DNA, sugars, and fats).
• The complexity and organization of organisms accommodates the need for obtaining, transforming, transporting, releasing, and eliminating the matter and energy used to sustain the organism.
• The distribution and abundance of organisms and populations in ecosystems are limited by the availability of matter and energy and the ability of the ecosystem to recycle materials.
• As matter and energy flows through different levels of organization of living systems-cells, organs, organisms, communities-and between living systems and the physical environment, chemical elements are recombined in different ways. Each recombination results in storage and dissipation of energy into the environment as heat. Matter and energy are conserved in each change.

Fundamental concepts that underlie the the Interdependence of Organisms include:

• The atoms and molecules on the earth cycle among the living and nonliving components of the biosphere.(Tropical Poison, and Temperate Rainforest)
• Energy flows through ecosystems in one direction, from photosynthetic organisms to herbivores to carnivores and decomposers.(Tropical Poison, and Temperate Rainforest)
• Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these organisms may generate ecosystems that are stable for hundreds or thousands of years.
• Living organisms have the capacity to produce populations of infinite size, but environments and resources are finite. This fundamental tension has profound effects on the interactions between organisms.
• Human beings live within the world's ecosystems. Increasingly, humans modify ecosystems as a result of population growth, technology, and consumption.
• Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening current global stability, and if not addressed, ecosystems will be irreversibly affected.

Fundamental concepts that underlie the the Behavior of Organisms include:

• Organisms have behavioral responses to internal changes and to external stimuli.
• Responses to external stimuli can result from interactions with the organism's own species and others, as well as environmental changes; these responses either can be innate or learned.
• The broad patterns of behavior exhibited by animals have evolved to ensure reproductive success. Animals often live in unpredictable environments, and so their behavior must be flexible enough to deal with uncertainty and change. Plants also respond to stimuli.
• Like other aspects of an organism's biology, behaviors have evolved through natural selection. Behaviors often have an adaptive logic when viewed in terms of evolutionary principles.

Content Standard F: Science in Personal & Social Perpectives (pp. 193-199)

Fundamental concepts that underlie Personal & Community Health include:

• The severity of disease symptoms is dependent on many factors, such as human resistance and the virulence of the disease-producing organism.
• Many diseases can be prevented, controlled, or cured. Some diseases, such as cancer, result from specific body dysfunctions and cannot be transmitted.
• Personal and social factors- such as habits, family income, ethnic heritage, body size, advertising, and peer pressure-influence nutritional choices.

Fundamental concepts that underlie Population Growth include:

• Populations grow or decline through the combined effects of births and deaths, and through emigration and immigration.
• Populations can increase through linear or exponential growth, with effects on resource use and environmental pollution.
• Various factors influence birth rates and fertility rates, such as average levels of affluence and education, importance of children in the labor force, education and employment of women, infant mortality rates, costs of raising children, availability and reliability of birth control methods, and religious beliefs and cultural norms that influence personal decisions about family size.
• Populations can reach limits to growth. Carrying capacity is the maximum number of individuals that can be supported in a given environment. The limitation is not the availability of space, but the number of people in relation to resources and the capacity of earth systems to support human beings.
• Changes in technology can cause significant changes, either positive or negative, in carrying capacity.

Fundamental concepts that underlie Natural Resources include:

• Human populations use resources in the environment in order to maintain and improve their existence.
• Natural resources have been and will continue to be used to maintain human populations. -
• The earth does not have infinite resources; increasing human consumption places severe stress on the natural processes that renew some resources, and it depletes those resources that cannot be renewed.
• Humans use many natural systems as resources. Natural systems have the capacity to reuse waste, but that capacity is limited. Natural systems can change to an extent that exceeds the limits of organisms to adapt naturally or humans to adapt technologically.

Fundamental concepts that underlie Environmental Quality include:

• Natural ecosystems provide an array of basic processes that affect humans. Those processes include maintenance of the quality of the atmosphere, generation of soils, control of the hydrologic cycle, disposal of wastes, and recycling of nutrients.
• Humans are changing many of these basic processes, and the changes may be detrimental to humans.
• Materials from human societies affect both physical and chemical cycles of the earth. Many factors influence environmental quality.
• Factors that students might investigate include population growth, resource use, population distribution, overconsumption, the capacity of technology to solve problems, poverty, the role of economic, political, and religious views, and different ways humans view the earth.

Fundamental concepts that underlie Natural & Human-Included Hazards include:

• Normal adjustments of earth may be hazardous for humans.
• Humans live at the interface between the atmosphere driven by solar energy and the upper mantle where convection creates changes in the earth's solid crust.
• As societies have grown, become stable, and come to value aspects of the environment, vulnerability to natural processes of change has increased. Human activities can enhance potential for hazards.
• Acquisition of resources, urban growth, and waste disposal can accelerate rates of natural change.
• Some hazards, such as earthquakes, volcanic eruptions, and severe weather, are rapid and spectacular.
• There are slow and progressive changes that also result in problems for individuals and societies. For example, change in stream channel position, erosion of bridge foundations, sedimentation in lakes and harbors, coastal erosions, and continuing erosion and wasting of soil and landscapes can all negatively affect society.
• Natural and human-induced hazards present the need for humans to assess potential danger and risk.
• Many changes in the environment designed by humans bring benefits to society, as well as cause risks.
• Students should understand the costs and trade-offs of various hazards-ranging from those with minor risk to a few people to major catastrophes with major risk to many people.
• The scale of events and the accuracy with which scientists and engineers can (and cannot) predict events are important considerations.

Fundamental concepts that underlie Science & Technology in Local, National, & Global Challenges include:

• Science and technology are essential social enterprises, but alone they can only indicate what can happen, not what should happen. The latter involves human decisions about the use of knowledge.
• Understanding basic concepts and principles of science and technology should precede active debate about the economics, policies, politics, and ethics of various science- and technology-related challenges. However, understanding science alone will not resolve local, national, or global challenges.
• Progress in science and technology can be affected by social issues and challenges. Funding priorities for specific health problems serve as examples of ways that social issues influence science and technology.
• Individuals and society must decide on proposals involving new research and the introduction of new technologies into society.
• Decisions involve assessment of alternatives, risks, costs, and benefits and consideration of who benefits and who suffers, who pays and gains, and what the risks are and who bears them.
• Students should understand the appropriateness and value of basic questions-"What can happen?"- "What are the odds?"-and "How do scientists and engineers know what will happen?"
• Humans have a major effect on other species. For example, the influence of humans on other organisms occurs through land use-which decreases space available to other species-and pollution-which changes the chemical composition of air, soil, and water.

Content Standard E: Science & Technology (pp. 190-193)

Fundamental concepts that underlie Abilities of Technological Design include:

• Identify a problem or design an opportunity.
• Propose designs choose between alternative solutions.
• Implement a proposed solution.
• Evaluate the solution and its consequences.
• Communicate the problem, process, and solution.

Fundamental concepts that underlie Understandings About Science & Technology include:

• Scientists in different disciplines ask different questions, use different methods of investigation, and accept different types of evidence to support their explanations.Many scientific investigations require the contributions of individuals from diffe ent disciplines, including engineering.
• New disciplines of science, such as geophysics and biochemistry often emerge at the interface of two older discplines.
• Science often advances with the introduction of new technologies. Solving technological problems often results in new scientific knowledge.
• New technologies often extend the current levels of scientific understanding and introduce new areas of research.
• Creativity, imagination, and a good knowledge base are all required in the work of science and engineering.
• Science and technology are pursued for different purposes. Scientific inquiry is driven by the desire to understand the natural world, and technological design is driven by the need to meet human needs and solve human problems.
• Technology, by its nature, has a more direct effect on society than science because its purpose is to solve human problems, help humans adapt, and fulfill human aspirations.
• Technological solutions may create new problems. Science, by its nature, answers questions that may or may not directly influence humans. Sometimes scientific advances challenge people's beliefs and practical explanations concerning various aspects of the world.

Content Standard G: History & Nature of Science (pp. 200-201)

Fundamental concepts that underlie Science As a Human Endeavor include:

• Individuals and teams have contributed and will continue to contribute to the scientific enterprise.
• Pursuing science as a career or as a hobby can be both fascinating and intellectually rewarding.
• Scientists have ethical traditions. Scientists value peer review, truthful reporting about the methods and outcomes of investigations, and making public the results of work. Violations of such norms do occur, but scientists responsible for such violations are censured by their peers.
• Scientists are influenced by societal, cultural, and personal beliefs and ways of viewing the world. Science is not separate from society but rather science is a part of society.

Fundamental concepts that underlie Nature of Scientific Knowledge include:

• Science distinguishes itself from other ways of knowing and from other bodies of knowledge through the use of empirical
• Standards, logical arguments, and skepticism, as scientists strive for the best possible explanations about the natural world.
• Scientific explanations must meet certain criteria. First and foremost, they must be consistent with experimental and observational evidence about nature, and must make accurate predictions, when appropriate, about systems being studied.
• Scientific explanations should also be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public.
• Explanations on how the natural world changes based on myths, personal beliefs, religious values, mystical inspiration, superstition, or authority may be personally useful and socially relevant, but they are not scientific.
• Because all scientific ideas depend on experimental and observational confirmation, all scientific knowledge is, in principle, subject to change as new evidence becomes available.
• The core ideas of science such as the conservation of energy or the laws of motion have been subjected to a wide variety of confirmations and are therefore unlikely to change in the areas in which they have been tested.
• In areas where data or understanding are incomplete, such as the details of human evolution or questions surrounding global warming, new data may well ead to changes in current ideas or resolve current conflicts.
• In situations where information is still fragmentary, it is normal for scientific ideas to be incomplete, but this is also where the opportunity for making advances may be greatest.

Content Standard: Chapter 11, Common Themes

11A Systems:

• A system usually has some properties that are different from those of its parts, but appear because of the interaction of those parts.
• Understanding how things work and designing solutions to problems of almost any kind can be facilitated by systems analysis.
• In defining a system, it is important to specify its boundaries and subsystems, indicate its relation to other systems, and identify what its input and its output are expected to be.
• The successful operation of a designed system usually involves feedback. The stability of a system can be greater when it includes appropriate feedback mechanisms.
• Even in some very simple systems, it may not always be possible to predict accurately the result of changing some part or connection.

11C Constancy and Change:

• A system in equilibrium may return to the same state of equilibrium if the disturbances it experiences are small.
• Large disturbances may cause it to escape that equilibrium and eventually settle into some other state of equilibrium.
• Things can change in detail but remain the same in general (the players change, but the team remains; cells are replaced, but the organism remains).
• Graphs and equations are useful (and often equivalent) ways for depicting and analyzing patterns of change.
• In many physical, biological, and social systems, changes in one direction tend to produce opposing (but somewhat delayed) influences, leading to repetitive cycles of behavior.
• In evolutionary change, the present arises from the materials and forms of the past, more or less gradually, and in ways that can be explained.
• Most systems above the molecular level involve so many parts and forces and are so sensitive to tiny differences in conditions that their precise behavior is unpredictable, even if all the rules for change are known.
• Predictable or not, the precise future of a system is not completely determined by its present state and circumstances but also depends on the fundamentally uncertain outcomes of events on the atomic scale.

11D Scale:

• Because different properties are not affected to the same degree by changes in scale, large changes in scale typically change the way that things work in physical, biological, or social systems.
• As the number of parts of a system grows in size, the number of possible internal interactions increases much more rapidly, roughly with the square of the number of parts.

Content Standard: Chapter 1, The Nature of Science

1A The Scientific World View:

• Scientists assume that the universe is a vast single system in which the basic rules are the same everywhere.
• Change and continuity are persistent features of science.
• In science, the testing, revising, and occasional discarding of theories, new and old nerer ends.
• Science is an ongoing process leads to an increasingly better understanding of how things work in the world but not to absolute truth.

1B Scientific Inquiry:

• Investigations are conducted for different reasons, including to explore new phenomena, to check on previous results, to test how well a theory predicts, and to compare different theories.
• Hypotheses are widely used in science for choosing what data to pay attention to and what additional data to seek, and for guiding the interpretation of the data (both new and previously available).
• Sometimes, scientists can control conditions in order to obtain evidence. When that is not possible for practical or ethical reasons, they try to observe as wide a range of natural occurrences as possible to be able to discern patterns.
• There are different traditions in science about what is investigated and how, but they all have in common certain basic beliefs about the value of evidence, logic, and good arguments. And there is agreement that progress in all fields of science depends on intelligence, hard work, imagination, and even chance.
• Scientists in any one research group tend to see things alike, so even groups of scientists may have trouble being entirely objective about their methods and findings. For that reason, scientific teams are expected to seek out the possible sources of bias in the design of their investigations and in their data analysis. Checking each other's results and explanations helps, but that is no guarantee against bias.

1C The Scientific Enterprise:

• Science disciplines differ from one another in what is studied, techniques used, and outcomes sought, but they share a common purpose and philosophy, and all are part of the same scientific enterprise.
• Many problems are studied by scientists using information and skills from many disciplines.
• Disciplines do not have fixed boundaries, and it happens that new scientific disciplines are being formed where existing ones meet and that some subdisciplines spin off to become new disciplines in their own right.
• Scientists can bring information, insights, and analytical skills to bear on matters of public concern.
• Scientists as a group can be expected to be no less biased than other groups are about their perceived interests.
• The strongly held traditions of science, including its commitment to peer review and publication, serve to keep the vast majority of scientists well within the bounds of ethical professional behavior. Deliberate deceit is rare and likely to be exposed sooner or later by the scientific enterprise itself.
• Funding influences the direction of science by virtue of the decisions that are made on which research to support.

Content Standard: Chapter 4, The Physical Setting

4C Processes that Shape the Earth:

• Plants alter the earth's atmosphere by removing carbon dioxide, using the carbon to make sugars and releasing oxygen. This process is responsible for the oxygen content of the air.
• The formation, weathering, sedimentation, and reformation of rock constitute a continuing "rock cycle" in which the total amount of material stays the same as its forms change.
• The slow movement of material within the earth results from heat flowing out from the deep interior and the action of gravitational forces on regions of different density.

4B The Earth:

• Life is adapted to conditions on the earth, including the force of gravity that enables the planet to retain an adequate atmosphere, and an intensity of radiation from the sun that allows water to cycle between liquid and vapor.
• Weather (in the short run) and climate (in the long run) involve the transfer of energy in and out of the atmosphere.
• Solar radiation heats the land masses, oceans, and air.
  

Content Standard: Chapter 5, The Living Environment

5B Heredity (Rift Valley Fever):

• Some new gene combinations make little difference, some can produce organisms with new and perhaps enhanced capabilities, and some can be deleterious.
• The sorting and recombination of genes in sexual reproduction results in a great variety of possible gene combinations from the offspring of any two parents.
• The information passed from parents to offspring is coded in DNA molecules.
• Genes are segments of DNA molecules. Inserting, deleting, or substituting DNA segments can alter genes.
• An altered gene may be passed on to every cell that develops from it. The resulting features may help, harm, or have little or no effect on the offspring's success in its environment.
• Gene mutations can be caused by such things as radiation and chemicals.
• When mutations occur in sex cells, the mutations can be passed on to offspring; if they occur in other cells, they can be passed on to descendant cells only.
• The experiences an organism has during its lifetime can affect its offspring only if the genes in its own sex cells are changed by the experience.
• The many body cells in an individual can be very different from one another, even though they are all descended from a single cell and thus have essentially identical genetic instructions.

5F Evolution of Life:

• The basic idea of biological evolution is that the earth's present-day species developed from earlier, distinctly different species.
• Natural selection provides the following mechanism for evolution:
  • Some variation in heritable characteristics exists within every species, some of these characteristics give individuals an advantage over others in surviving and reproducing, and the advantaged offspring, in turn, are more likely than others to survive and reproduce.
  • The result is the proportion of individuals that have advantageous characteristics for survival and reproduction will increase.
• New heritable characteristics can result from new combinations of existing genes or from mutations of genes in reproductive cells. Changes in other cells of an organism cannot be passed on to the next generation.
• Natural selection leads to higher proportions of organisms in a population that are well suited for survival in particular environments.
• Chance alone can result in the persistence of some heritable characteristics having no survival or reproductive advantage or disadvantage for the organism. When an environment changes, the survival value of some inherited characteristics may change.
• The theory of natural selection provides a scientific explanation for the history of life on earth as depicted in the fossil record and in the similarities evident within the diversity of existing organisms.
• Evolution builds on what already exists, so the more variety there is, the more there can be in the future. But evolution does not necessitate long-term progress in some set direction.
• Evolutionary changes appear to be like the growth of a bush: Some branches survive from the beginning with little or no change, many die out altogether, and others branch repeatedly, sometimes giving rise to more complex organisms.

5A Diversity of Life:

• The variation of organisms within a species increases the likelihood that at least some members of the species will survive under changed environmental conditions, and a great diversity of species increases the chance that at least some living things will survive in the face of large changes in the environment.
• The degree of kinship between organisms or species can be estimated from the similarity of their DNA sequences, which often closely matches their classification based on anatomical similarities.

5D Interdependence of Life:

• Ecosystems can be reasonably stable over hundreds or thousands of years. As any population of organisms grows, it is held in check by one or more environmental factors: depletion of food or nesting sites, increased loss to increased numbers of predators, or parasites. If a disaster such as flood or fire occurs, the damaged ecosystem is likely to recover in stages that eventually result in a system similar to the original one.
• Like many complex systems, ecosystems tend to have cyclic fluctuations around a state of rough equilibrium. In the long run, however, ecosystems always change when climate changes or when one or more new species appear as a result of migration or local evolution.
• Human beings are part of the earth's ecosystems.
• Human activities can, deliberately or inadvertently, alter the equilibrium in ecosystems.

5E Flow of Matter and Energy (Tropical Poison, and Temperate Rainforest):

• Layers of energy-rich organic material have been gradually turned into great coal beds and oil pools by the pressure of the overlying earth.
• By burning these fossil fuels, people are passing most of the stored energy back into the environment as heat and releasing large amounts of carbon dioxide.
• The amount of life any environment can support is limited by the available energy, water, oxygen, and minerals, and by the ability of ecosystems to recycle the residue of dead organic materials.
• Human activities and technology can change the flow and reduce the fertility of the land.
• The chemical elements that make up the molecules of living things pass through food webs and are combined and recombined in different ways.
• At each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat.
• Continual input of energy from sunlight keeps the process(Flow of Matter and Energy) going.

Content Standard: Chapter 7, Huaman Society

7A Cultural Effects on Behavior:

• Cultural beliefs strongly influence the values and behavior of the people who grow up in the culture, often without their being fully aware of it. Response to these influences varies among individuals.
• Social distinctions are a part of every culture, but take many different forms, ranging from rigid classes based solely on pare ntage to gradations based on the acquisition of skill, wealth, or education.
• Heredity, culture, and personal experience interact in shaping human behavior. Their relative importance in most circumstances is not clear.

7C Social Change:

• The size and rate of growth of the human population in any location is affected by economic, political, religious, technological, and environmental factors. Some of these factors, in turn, are influenced by the size and rate of growth of the population.
• The decisions of one generation both provide and limit the range of possibilities open to the next generation.
• Mass media, migrations, and conquest affect social change by exposing one culture to another.
• To various degrees, governments try to bring about social change or to impede it through policies, laws, incentives, or direct coercion. Sometimes such efforts achieve their intended results and sometimes they do not.

7D Social Trade-offs:

• Benefits and costs of proposed choices include consequences that are long-term as well as short-term, and indirect as well as direct.
• The more remote the consequences of a personal or social decision, the harder it usually is to take them into account in considering alternatives.
• Benifits and costs may be difficult to estimate.
• In deciding among alternatives, a major question is who will receive the benefits and who (not necessarily the same people) will bear the costs.
• Social trade-offs are often generational:
  • The cost of benefits received by one generation may fall on subsequent generations.
  • The cost of a social trade-off is sometimes borne by one generation although the benefits are enjoyed by their descendants.

7E Political and Economic Systems:

• In the free-market model, the control of production and consumption is mainly in private hands. The best allocation of resources is believed to be achieved by talent, and hard work are expected to be rewarded with success and wealth.
• Government's role is primarily to protect political and economic freedoms for society as a whole-even at the cost of some individual or group material benefits.
• In the central-planning model, production and consumption are controlled by the government.
• The main purpose of government is to promote comparable welfare for all individuals and groups-even at the cost of some individual and group freedoms.
• In practice, countries make compromises with regard to economic models. Central planning has to allow for some individual initiative, and markets have to provide some protection for unsuccessful competitors. The countries of the world use elements of both systems and are neither purely free-market nor entirely centrally controlled. Countries change, some adopting more free-market policies and practices, others more central-planning ones, and still others doing some of each.

7F Social Conflict:

• Conflict between people or groups arises from competition over ideas, resources, power, and status.
• Social change, or the prospect of it, promotes conflict because social, economic, and political changes usually benefit some groups more than others. That, of course, is also true of the status quo.
• Conflicts are especially difficult to resolve in situations in which there are few choices and little room for compromise. Some informal ways of responding to conflict-use of pamphlets, demonstrations, cartoons, etc.-may sometimes reduce tensions and lead to compromise but at other times they may be inflammatory and make agreement more difficult to reach.
• Conflict within a group may be reduced by conflict between it and other groups.
• Intergroup conflict does not necessarily end when one segment of society gets a decision in its favor, for the "losers" may then work all the harder to reverse, modify, or circumvent the change. Even when the majority of the people in a society agree on a social decision, the minority who disagree must be protected from oppression, just as the majority may need protection against unfair retaliation from the minority.

7G Global Interdependence:

• The wealth of a country depends partly on the effort and skills of its workers, its natural resources, and the capital and technology available to it.
• The wealth of a country also depends on the balance between how much its products are sought by other nations and how much of other nations' products it seeks.
• Even if a country could produce everything it needs for itself, it would still benefit from trade with other countries.
• Because of increasing international trade, the domestic products of any country may be made up in part by parts made in other countries.
• The international trade picture is often complicated by political motivations taking priority over economic ones.
• The growing interdependence of world social, economic, and ecological systems does not always bring greater worldwide stability and often increases the costs of conflict.

Content Standards: Chapter 8 ,The Designed World

8A Agriculture:

• New varieties of farm plants and animals have been engineered by manipulating their genetic instructions to produce new characteristics.
• Government sometimes intervenes in matching agricultural supply to demand in an attempt to ensure a stable, high-quality, and inexpensive food supply.
• Regulations are often also designed to protect farmers from abrupt changes in farming conditions and from competition by farmers in other countries.
• Agricultural technology requires trade-offs between increased production and environmental harm and between efficient production and social values. In the past century, agricultural technology led to a huge shift of population from farms to cities and a great change in how people live and work.

8F Health Technology (Rift Vlley Fever):

• Owing to the large amount of information that computers can process, they are playing an increasingly larger role in medicine to analyze data and to keep track of diagnostic information about individuals and statistical information on the distribution and spread of various maladies in populations.
• Almost all body substances and functions have daily or longer cycles. These cycles often need to be taken into account in interpreting normal ranges for body measurements, detecting disease, and planning treatment of illness.
• Knowledge of genetics is opening whole new fields of health care:
  • In treatment, substances from genetically engineered organisms may reduce the cost and side effects of replacing missing body chemicals.
  • Inoculations use weakened germs (or parts of them) to stimulate the
• The body's immune system to react. This reaction prepares the body to fight subsequent invasions by actual germs of that type.
• Some inoculations last for life.
• The diagnosis and treatment of mental disorders are improving but not as rapidly as for physical health.
• Biotechnology has contributed to health improvement in many ways, but its cost and application have led to a variety of controversial social and ethical issues.

Content Standards: Chapter 12, Habitats of Mind

12A Values and Attitudes:

• Know why curiosity, honesty, openness, and skepticism are so highly regarded in science and how they are incorporated into the way science is carried out; exhibit those traits in their own lives and value them in others.
• View science and technology thoughtfully, being neither categorically antagonistic nor uncritically positive.

12B Computation and Estimation in appropriate problems:

• Find answers to problems by substitu ting numerical values in simple algebraic formulas and judge whether the answer is reasonable by reviewing the process and checking against typical values.
• Make up and write out simple algorithms for solving problems that take several steps.
• Use computer spreadsheet, graphing, and database programs to assist in quantitative analysis.
• Compare data for two groups by representing their averages and spreads graphically.
• Express and compare very small and very large numbers using powers-of-ten notation.
• Trace the source of any large disparity between an estimate and the calculated answer.
• Consider the possible effects of measurement errors on calculations.

12C Manipulation and Observation:

• Learn quickly the proper use of new instruments by following instructions in manuals or by taking instructions from an experienced user.
• Use computers for producing tables and graphs and for making spreadsheet calculations.

12D Communication Skills:

• Make and interpret scale drawings.
• Write clear, step-by-step instructions for conducting investigations, operating something, or following a procedure.
• Choose appropriate summary statistics to describe group differences, always indicating the spread of the data as well as the data's central tendencies.
• Describe spatial relationships in geometric terms such as perpendicular, parallel, tangent, similar, congruent, and symmetrical.
• Use and correctly interpret relational terms such as if . . . then . . . , and, or, sufficient, necessary, some, every, not, correlates with, and causes.
• Participate in group discussions on scientific topics by restating or summarizing accurately what others have said, asking for clarification or elaboration, and expressing alternative positions.
• Use tables, charts, and graphs in making arguments and claims in oral and written presentations.

12E Critical-Response Skills:

• Notice and criticize arguments based on the faulty, incomplete, or misleading use of numbers, such as in instances when:
  • Average results are reported, but not the amount of variation around the average
  • Check graphs to see that they do not misrepresent results by using inappropriate scales or by failing to specify the axes clearly.
  • Wonder how likely it is that some event of interest might have occurred just by chance.
  • Insist that the critical assumptions behind any line of reasoning be made explicit so that the validity of the position being taken-whether one's own or that of others-can be judged.
  • Be aware, when considering claims, that when people try to prove a point, they may select only the data that support it and ignore any that would contradict it.
• Suggest alternative ways of explaining data and criticize arguments in which data, explanations, or conclusions are represented as the only ones worth consideration, with no mention of other possibilities. Similarly, suggest alternative trade-offs in decisions and designs and criticize those in which major trade-offs are not acknowledged.