The text following the standard describes some of the difficulties that students can have in comprehending the basic concepts of evolution.
Students have difficulty with the fundamental concepts of evolution. For example, students often do not understand natural selection because they fail to make a conceptual connection between the occurrence of new variations in a population and the potential effect of those variations on the long-term survival of the species. One misconception that teachers may encounter involves students attributing new variations to an organism's need, environmental conditions, or use. With some help, students can understand that, in general, mutations occur randomly and are selected because they help some organisms survive and produce more offspring. Other misconceptions center on a lack of understanding of how a population changes as a result of differential reproduction (some individuals producing more offspring), as opposed to all individuals in a population changing. Many misconceptions about the process of natural selection can be changed through instruction.
Finally, evolution is discussed again in the guidance following the earth and space science standard:
As a result of their activities in grades 9–12, all students should develop an understanding of:
Energy in the earth system
Origin and evolution of the earth system
Origin and evolution of the universe
The discussions of the origin and evolution of the earth system and the universe relate evolution to universal physical processes:
The Origin and Evolution of the Earth System
The sun, the earth, and the rest of the solar system formed from a nebular cloud of dust and gas 4.5 billion years ago. The early earth was very different from the planet we live on today.
Geologic time can be estimated by observing rock sequences and using fossils to correlate the sequences at various locations. Current methods include using the known decay rates of radioactive isotopes present in rocks to measure the time since the rock was formed.
Interactions among the solid earth, the oceans, the atmosphere, and organisms have resulted in the ongoing evolution of the earth system. We can observe some changes such as earthquakes and volcanic eruptions on a human time scale, but many processes such as mountain building and plate movements take place over hundreds of millions of years.
Evidence for one-celled forms of life—the bacteria—extends back more than 3.5 billion years. The evolution of life caused dramatic changes in the composition of the earth's atmosphere, which did not originally contain oxygen.
The Origin and Evolution of the Universe
The origin of the universe remains one of the greatest questions in science. The "big bang" theory places the origin between 10 and 20 billion years ago, when the universe began in a hot dense state; according to this theory, the universe has been expanding ever since.
Early in the history of the universe, matter, primarily the light atoms hydrogen and helium, clumped together by gravitational attraction to form countless trillions of stars. Billions of galaxies, each of which is a gravitationally bound cluster of billions of stars, now form most of the visible mass in the universe.
Stars produce energy from nuclear reactions, primarily the fusion of hydrogen to form helium. These and other processes in stars have led to the formation of all the other elements.
The standard for the history and nature of science elaborates on the knowledge established in previous years:
As a result of activities in grades 9–12, all students should develop an understanding of:
Science as a human endeavor
Nature of scientific knowledge
The discussion of this standard relates the nature of science explicitly to many of the problems that arise in the teaching of evolution.
Nature of Scientific Knowledge
Science distinguishes itself from other ways of