Science Backstory
Project 2061, Benchmarks for Science Literacy, maps national science standards into a coherent conceptual framework. This page identifies the concept strands covered in the game from the perspective of these benchmarks.
(from Project 2061 Benchmarks for Science Literacy, 1994)
The basic idea of biological evolution is that present day species developed from earlier distantly different species.
Most of the species that have lived on the earth no longer exist. Extinction of species is common. (Fossils indicate that most species that lived long ago are extinct.)
Life on earth today are descendents of extinct species that have become extinct.
Biological evolution accounts for the diversity of species developed through gradual processes over many generations.
Natural selection is gradual, occurring over many generations. An individual organism does not adapt or evolve, but a species does. Reproduction is a characteristic of all living systems; because no individual organism lives forever, reproduction is essential to the continuation of every species.
Over long periods of time, natural selection leads to organisms well suited for survival in particular environments.
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.
(The biotic and physical conditions of a particular environment define an ecosystem.)
Changes in environmental conditions can affect the survival of individual organisms and entire species. Extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient to allow any organisms in that species to survive. Even though species becomes extinct, other species which evolved from a now extinct species may continue to survive and themselves evolve.
TREE OF LIFE:
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.
Life on earth is thought to have begun as a single one-celled organism about 4 billion years ago. Once cells with nuclei developed about a billion years ago, increasingly complex cellular organisms evolved.
