• Structure and function in living systems

  • Reproduction and heredity

  • Regulation and behavior

  • Populations and ecosystems

  • Diversity and adaptations of organisms

The guidance for this standard defines regulation and behavior as follows:

An organism's behavior evolves through adaptation to its environment. How a species moves, obtains food, reproduces, and responds to danger are based in the species' evolutionary history.

The text discusses diversity and adaptations as follows:

Diversity and Adaptations of Organisms

Millions of species of animals, plants, and microorganisms are alive today. Although different species might look dissimilar, the unity among organisms becomes apparent from an analysis of internal structures, the similarity of their chemical processes, and the evidence of common ancestry.

Biological evolution accounts for the diversity of species developed through gradual processes over many generations. Species acquire many of their unique characteristics through biological adaptation, which involves the selection of naturally occurring variations in populations. Biological adaptations include changes in structures, behaviors, or physiology that enhance survival and reproductive success in a particular environment.

Extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient to allow its survival. Fossils indicate that many organisms that lived long ago are extinct. Extinction of species is common; most of the species that have lived on the earth no longer exist.

The text accompanying the standard also discusses some of the difficulties encountered in teaching about adaptation:

Understanding adaptation can be particularly troublesome at this level. Many students think adaptation means that individuals change in major ways in response to environmental changes (that is, if the environment changes, individual organisms deliberately adapt).

In fact, as described in Chapter 2 of this book, adaptation occurs through natural selection, a topic described under the life science standards for grades 9–12.

The content standards also treat evolution in grades 5–8 in the section on earth's history. The standard reads as follows:



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