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Benchmarks

Benchmarks	Cell Structure & Function	Cells and You: Processes and Applications	Genetics Theory	Genetics Applications	Evolution
1. THE NATURE OF SCIENCE By the end of the 12th grade, students should know:
A. The Scientific World View
Scientists assume that the universe is a vast single system in which the basic rules are the same everywhere. ...  more
From time to time, major shifts occur in the scientific view of how the world works. ...  more
No matter how well one theory fits observations, a new theory might fit them just as well or better, or might fit a wider range of observations. ...  more
B. Scientific Inquiry
Investigations are conducted for different reasons. ...  more
Hypotheses are widely used in science. ...  more
Sometimes, scientists can control conditions in order to obtain evidence. ...  more
There are different traditions in science about what is investigated and how. ...  more
Scientists in any one research group tend to see things alike. ...  more
...theories are judged by how they fit with other theories. ...  more
New ideas in science are limited by the context in which they are conceived. ...  more
C. The Scientific Enterprise
The early Egyptian, Greek, Chinese, Hindu, and Arabic cultures are responsible for many scientific and mathematical ideas and technological inventions  more
Modern science is based on traditions. ...  more
Progress in science and invention depends heavily on what else is happening in society. ...  more
Science disciplines differ from one another. ...  more
Current ethics in science. ...  more
Scientists can bring information, insights, and analytical skills to bear on matters of public concern  more
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  more
Funding influences the direction of science by virtue of the decisions that are made on which research to support  more
3. THE NATURE OF TECHNOLOGY By the end of the 12th grade, students should know:
A. Technology and Science
...new technologies make it possible for scientists to extend their research in new ways. ...  more
Mathematics, creativity, logic and originality are all needed to improve technology  more
Technology usually affects society more directly than science. ...  more
4. THE PHYSICAL SETTING By the end of the 12th grade, students should know:
A. The Universe
The stars differ from each other in size, temperature, and age. ...  more
On the basis of scientific evidence, the universe is estimated to be over ten billion years old. ...  more
Increasingly sophisticated technology is used to learn about the universe. ...  more
Mathematical models and computer simulations are used in studying evidence from many sources in order to form a scientific account of the universe  more
B. The Earth
Life is adapted to conditions on the earth, including the force of gravity. ...  more
Weather (in the short run) and climate (in the long run) involve the transfer of energy in and out of the atmosphere. ...  more
C. Processes that Shape the Earth
Plants alter the earth's atmosphere by removing carbon dioxide from it, using the carbon to make sugars and releasing oxygen. ...  more
The formation, weathering, sedimentation, and reformation of rock constitute a continuing "rock cycle". ...  more
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  more
The solid crust of the earth consists of separate plates. ...  more
Earthquakes often occur along the boundaries between colliding plates. ...  more
D. The Structure of Matter
Atoms are made of a positive nucleus surrounded by negative electrons. ...  more
The nucleus ... is composed of protons and neutrons, each almost two thousand times heavier than an electron. ...  more
Neutrons have a mass that is nearly identical to that of protons, but neutrons have no electric charge. ...  more
The nucleus of radioactive isotopes is unstable and spontaneously decays, emitting particles and/or wavelike radiation. ...  more
Scientists continue to investigate atoms and have discovered even smaller constituents of which electrons, neutrons, and protons are made  more
When elements are listed in order by the masses of their atoms, the same sequence of properties appears over and over again in the list  more
Atoms often join with one another in various combinations in distinct molecules or in repeating three-dimensional crystal patterns. ...  more
The configuration of atoms in a molecule determines the molecule's properties. ...  more
The rate of reactions among atoms and molecules depends on how often they encounter one another. ...  more
E. Energy Transformations
Whenever the amount of energy in one place or form diminishes, the amount in other places or forms increases by the same amount  more
Heat energy in a material consists of the disordered motions of its atoms or molecules. ...  more
Transformations of energy usually produce some energy in the form of heat, which spreads around by radiation or conduction into cooler places. ...  more
Different energy levels are associated with different configurations of atoms and molecules. ...  more
When energy of an isolated atom or molecule changes, it does so in a definite jump from one value to another, with no possible values in between. ...  more
Energy is released. ...  more
F. Motion
The change in motion of an object is proportional to the applied force and inversely proportional to the mass  more
All motion is relative to whatever frame of reference is chosen, for there is no motionless frame from which to judge all motion  more
Accelerating electric charges produce electromagnetic waves around them. ...  more
Whenever one thing exerts a force on another, an equal amount of force is exerted back on it  more
The observed wavelength of a wave depends upon the relative motion of the source and the observer. ...  more
Waves can superpose on one another, bend around corners, reflect off surfaces, be absorbed by materials they enter, and change direction when entering a new material. ...  more
G. Forces of Nature
Gravitational force is an attraction between masses. ...  more
Electromagnetic forces acting within and between atoms are vastly stronger than the gravitational forces acting between the atoms. ...  more
There are two kinds of charges-positive and negative. ...  more
Different kinds of materials respond differently to electric forces. ...  more
Magnetic forces are very closely related to electric forces and can be thought of as different aspects of a single electromagnetic force. ...  more
The forces that hold the nucleus of an atom together are much stronger than the electromagnetic force. ...  more
5. THE LIVING ENVIRONMENT By the end of the 12th grade, students should know:
A. 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. ...  more
The degree of kinship between organisms or species can be estimated from the similarity of their DNA sequences. ...  more
B. Heredity
Some new gene combinations make little difference. ...  more
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  more
The information passed from parents to offspring is coded in DNA molecules  more
Genes are segments of DNA molecules. Inserting, deleting, or substituting DNA segments can alter genes. ...  more
Gene mutations can be caused by such things as radiation and chemicals. ...  more
The many body cells in an individual can be very different from one another. ...  more
C. Cells
Every cell is covered by a membrane that controls what can enter and leave the cell. ...  more
Within every cell are specialized parts for the transport of materials, energy transfer, protein building, waste disposal, information feedback, and even movement. ...  more
The work of the cell is carried out by the many different types of molecules it assembles, mostly proteins. ...  more
The genetic information encoded in DNA molecules provides instructions for assembling protein molecules. ...  more
Complex interactions among the different kinds of molecules in the cell cause distinct cycles of activities, such as growth and division. ...  more
Gene mutation in a cell can result in uncontrolled cell division, called cancer. ...  more
Most cells function best within a narrow range of temperature and acidity. ...  more
A living cell is composed of a small number of chemical elements. ...  more
D. Interdependence of Life
Ecosystems can be reasonably stable over hundreds or thousands of years. ...  more
Like many complex systems, ecosystems tend to have cyclic fluctuations around a state of rough equilibrium. ...  more
Human beings are part of the earth's ecosystems. Human activities can, deliberately or inadvertently, alter the equilibrium in ecosystems  more
E. Flow of Matter and Energy
At times, ... plants and marine organisms grow faster than decomposers can recycle them back to the environment. ...  more
The amount of life any environment can support is limited. ...  more
The chemical elements that make up the molecules of living things pass through food webs. ...  more
F. Evolution of Life
The basic idea of biological evolution is that the earth's present-day species developed from earlier, distinctly different species  more
Molecular evidence substantiates the anatomical evidence for evolution. ...  more
Natural selection provides the following mechanism for evolution  more
Heritable characteristics can be observed at molecular and whole-organism levels-in structure, chemistry, or behavior. ...  more
New heritable characteristics can result from new combinations of existing genes or from mutations of genes in reproductive cells. ...  more
Natural selection leads to organisms that are well suited for survival in particular environments. ...  more
The theory of natural selection provides a scientific explanation for the history of life on earth. ...  more
Life on earth is thought to have begun as simple, one-celled organisms about 4 billion years ago. ...  more
Evolution builds on what already exists, so the more variety there is, the more there can be in the future. ...  more
6. THE HUMAN ORGANISM By the end of the 12th grade, students should know:
A. Human Identity
The similarity of human DNA sequences and the resulting similarity in cell chemistry and anatomy identify human beings as a single species  more
Written records and photographic and electronic devices enable human beings to share, compile, use, and misuse great amounts of information and misinformation. ...  more
B. Human Development
As successive generations of an embryo's cells form by division, small differences in their immediate environments cause them to develop slightly differently. ...  more
Using artificial means to prevent or facilitate pregnancy raises questions. ...  more
The very long period of human development ... is associated with the prominent role of the brain in human evolution. ...  more
The development and use of technologies to maintain, prolong, sustain, or terminate life raise social, moral, ethical, and legal issues  more
C. Basic Functions
The immune system is designed to protect. ...  more
The nervous system works by electrochemical signals in the nerves and from one nerve to the next. ...  more
Communication between cells is required to coordinate their diverse activities. ...  more
Reproduction is necessary for the survival of any species. ...  more
D. Learning
Differences in the behavior of individuals arise from the interaction of heredity and experience. ...  more
The expectations, moods, and prior experiences of human beings can affect how they interpret new perceptions or ideas. ...  more
Human thinking involves the interaction of ideas, and ideas about ideas. ...  more
E. Physical Health
Some allergic reactions are caused by the body's immune responses to usually harmless environmental substances. ...  more
Faulty genes can cause body parts or systems to work poorly. ...  more
New medical techniques, ... give today's human beings a better chance of staying healthy than their forebears had. ...  more
Some viral diseases, such as AIDS, destroy critical cells of the immune system. ...  more
F. Mental Health
Stresses are especially difficult for children to deal with. ...  more
Biological abnormalities, ... can cause or increase susceptibility to psychological disturbances  more
Reactions of other people to an individual's emotional disturbance may increase its effects  more
Human beings differ greatly in how they cope with emotions and may therefore puzzle one another  more
Ideas about what constitutes good mental health and proper treatment for abnormal mental states vary. ...  more
8. THE DESIGNED WORLD By the end of the 12th grade, students should know:
A. Agriculture
New varieties of farm plants and animals have been engineered. ...  more
Government sometimes intervenes in matching agricultural supply to demand in an attempt to ensure a stable, high-quality, and inexpensive food supply. ...  more
Agricultural technology requires trade-offs between increased production and environmental harm and between efficient production and social values. ...  more
F. Health Technology
Owing to the large amount of information that computers can process, they are playing an increasingly larger role in medicine. ...  more
Almost all body substances and functions have daily or longer cycles. ...  more
Knowledge of genetics is opening whole new fields of health care. ..  more
Inoculations use weakened germs (or parts of them) to stimulate the body's immune system to react. ..  more
Knowledge of molecular structure and interactions aids in synthesizing new drugs and predicting their effects  more
The diagnosis and treatment of mental disorders are improving but not as rapidly as for physical health. ...  more
Biotechnology has contributed to health improvement in many ways. ...  more
10. HISTORICAL PERSPECTIVES By the end of the 12th grade, students should know:
H. Explaining the Diversity of Life
The scientific problem that led to the theory of natural selection was how to explain similarities within the great diversity of existing and fossil organisms  more
Prior to Charles Darwin, the most widespread belief was that all known species were created at the same time and remained unchanged throughout history. ...  more
Darwin argued that only biologically inherited characteristics could be passed on to offspring  more
The quick success of Darwin's book Origin of Species came from the clear and understandable argument it made ...  more
After the publication of Origin of Species, biological evolution was supported by the rediscovery of the genetics experiments of an Austrian monk, Gregor Mendel. ...  more
By the 20th century, most scientists had accepted Darwin's basic idea. ...  more
11. COMMON THEMES By the end of the 12th grade, students should know:
A. Systems
A system usually has some properties that are different from those of its parts, but appear because of the interaction of those parts  more
Understanding how things work and designing solutions to problems of almost any kind can be facilitated by systems analysis. ...  more
The successful operation of a designed system usually involves feedback. ...  more
Even in some very simple systems, it may not always be possible to predict accurately the result of changing some part or connection  more
C. Constancy and Change
A system in equilibrium may return to the same state of equilibrium. ...  more
...the concept of the conservation of matter led to revolutionary advances in chemical science. ...  more
Things can change in detail but remain the same in general...  more
Graphs and equations are useful (and often equivalent) ways for depicting and analyzing patterns of change  more
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  more
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  more
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. ...  more
12. HABITS OF MIND By the end of the 12th grade, students should know:
A. Values and Attitudes
Know why curiosity, honesty, openness, and skepticism are so highly regarded in science. ...  more
View science and technology thoughtfully, being neither categorically antagonistic nor uncritically positive  more
D. Communication Skills
Make and interpret scale drawings  more
Write clear, step-by-step instructions for conducting investigations, operating something, or following a procedure  more
Choose appropriate summary statistics. ...  more
Describe spatial relationships in geometric terms. ...  more
Use and correctly interpret relational terms such as if . . . then . . . , and, or, sufficient, necessary, some, every, not, correlates with, and causes  more
Participate in group discussions on scientific topics  more
Use tables, charts, and graphs in making arguments and claims in oral and written presentations  more
E. Critical-Response Skills
Notice and criticize arguments based on the faulty, incomplete, or misleading use of numbers. ...  more
Check graphs. ...  more
Wonder how likely it is that some event of interest might have occurred just by chance  more
Insist that the critical assumptions behind any line of reasoning be made explicit. ...  more
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  more
Suggest alternative ways of explaining data. ...  more

This is an edited version of the Benchmarks as they appear in the document  Science for All Americans as produced by the Project 2061 team from the American Association for the Advancement of Science

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