Science (2015) Grade(s): 7

SC15.7.16

Construct an explanation based on evidence (e.g., cladogram, phylogenetic tree) for the anatomical similarities and differences among modern organisms and between modern and fossil organisms, including living fossils (e.g., alligator, horseshoe crab, nautilus, coelacanth).

Unpacked Content

Scientific and Engineering Practices

Constructing Explanations and Designing Solutions

Crosscutting Concepts

Patterns

Knowledge

Students know:
  • Anatomical similarities and differences among organisms can be used to infer evolutionary relationships among modern organisms and fossil organisms.
  • Anatomical similarities and differences between modern organisms (e.g., skulls of modern crocodiles, skeletons of birds; features of modern whales and elephants).
  • Organisms that share a pattern of anatomical features are likely to be more closely related than are organisms that do not share a pattern of anatomical features, due to the cause-and-effect relationship between genetic makeup and anatomy (e.g., although birds and insects both have wings, the organisms are structurally very different and not very closely related; the wings of birds and bats are structurally similar, and the organisms are more closely related; the limbs of horses and zebras are structurally very similar, and they are more closely related than are birds and bats or birds and insects).

Skills

Students are able to:
  • Articulate a statement that relates a given phenomenon to a scientific idea, including anatomical similarities and differences among organisms.
  • Identify and use multiple valid and reliable sources of evidence to construct an explanation for anatomical similarities and differences among organisms.
  • Use reasoning to connect the evidence and support an explanation for anatomical similarities and differences among organisms.

Understanding

Students understand that:
  • Organisms that share a pattern of anatomical features are likely to be more closely related than organisms that do not share a pattern of anatomical features.
  • Changes over time in the anatomical features observable in the fossil record can be used to infer lines of evolutionary descent by linking extinct organisms to living organisms through a series of fossilized organisms that share a basic set of anatomical features.

Vocabulary

  • Explanation
  • Evidence
  • Cladogram
  • Phylogenetic tree
  • Anatomical similarities
  • Anatomical differences
  • Organism
  • Fossil
  • Living fossil
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