Grade 8Science

Focus: In this unit, students investigate the phenomenon of the similarities among organisms that seem to be related and ask questions about how these organisms are the same and different from fossils that have similar structures. What can explain the interconnectedness of these organisms? The subtitle of this unit is How could living things today be connected to the things that lived long ago? Starting with an examination of extant and fossil penguins, student undertake the process of seeing both morphological similarities and differences. Then by examining horses and horseshoe crabs, students expand their understanding of connections between things that lived in the past and those that are living now. Step by step students develop a model that might explain how organisms change over time.  They examine the possible role of environment as they develop models of natural selection and possible common ancestry. This unit allows students to observe the phenomenon of a force acting through a distance in detail and then spend time working with classmates to analyze the shared experience, formulate new questions, and developing new strategies for answering them. Students explore concepts that include the following:

  • How could penguins and other things living today be connected to the things that lived long ago?
  • Why are there similarities and differences in the body structures of modern and ancient penguins?
  • How could organisms living today be connected to organisms that lived long ago?
  • How do traits found in a population change over a shorter amount of time?
  • How well does our General Model predict and explain the changes happening over time in a different population?
  • Can we apply the General Model for Natural Selection over millions of years to explain how all the ancient and modern penguins are connected?

As students move through their day-to-day activities, they will also read Core Knowledge literacy selections. These include factual articles, history of the sciences, art and literature, spotting bad science in the media and advertisements, graphics comprehension, research-type articles, reliability of sources, and other areas of science literacy.

Lesson Numbers:

  • Teacher Guide: 15 Lessons
  • Student Reader: 4 Collections

Lesson time:

  • Lessons can be completed in one or more class periods.
  • A Pacing Guide, found in Online Resources, offers the suggestion that the entire unit should take about 31 days if class is held each day.
  • A complete list of materials needed to complete the unit is also provided in the Online Resources.
  • The Core Knowledge Student Reader includes on reading collection per week for every week of the unit. A week’s reading collection relates to the lessons completed in the previous week.
    • The reading is assigned at the beginning of the week with the accompanying writing exercise due at the end of the week.
    • The reading and writing exercises are designed to be completed by students independently with brief, supporting, teacher-facilitated discussions at the beginning, midpoint, and end of the week.

Additional Search Terms for the Student Reader:

• science literacy • evolution • natural selection • common ancestry • fossil record • species • mass extinction • convergence • phylogeny • adaptation • artificial selection • speciation • nonfiction • informational text

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