Alaska Science
Key Element A13

A student who meets the content standard should understand the theory of natural selection as an explanation for evidence of changes in life forms over time (Evolution and Natural Selection).

Performance Standard Level 3, Ages 11–14

Students use information found in the fossil record to provide evidence for the history of Earth and its changing life forms.

Sample Assessment Ideas

• Students use sets of cards with preprinted information relating to fossils and geologic events, to organize a time line.

• Students describe how a variety of organisms (including plants, animals, and insects) become fossils; examine how fossil evidence gives information about organisms.

Expanded Sample Assessment Idea

• Students use a set of fossilized footprints to conjecture what might have occurred; compare results of their speculations.

Procedure

Students will:

1. Analyze a set of fossilized tracks; use the available evidence to reconstruct a series of events.

2. As a class, discuss alternative explanations; differentiate between evidence and inference.

3. Design their own footprint puzzle; give it to another group to analyze.

4. Diagram footprint evidence that could lead to several different, yet defensible, explanations regarding the specific event that took place involving the two or more people or animals from the puzzle.

5. Students participate in a mock scientific conference in which they defend their best explanation for what happened after studying the fossil footprint puzzle.

Reflection and Revision

Explain the strengths and weaknesses of each explanation.

Levels of Performance

Standards Cross-References
( Alaska Department of Education & Early Development Standards)

National Science Education Standards

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. (Page 158)

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. (Page 158)

Benchmarks

Small differences between parents and offspring can accumulate (through selective breeding) in successive generations so that descendants are very different from their ancestors. (Page 124)

Individual organisms with certain traits are more likely than others to survive and have offspring. Changes in environmental conditions can affect the survival of individual organisms and entire species. (Page 124)

Many thousands of layers of sedimentary rock provide evidence for the long history of the Earth and for the long history of changing life forms whose remains are found in the rocks. More recently deposited rock layers are more likely to contain fossils resembling existing species. (Page 124)