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Science · Grade 9

Evolution and Evidence

Learners explain natural selection as a mechanism acting on heritable variation, weigh fossil, anatomical, embryological, molecular and biogeographic evidence for common ancestry, and measure evolution as changing allele frequencies, including the role of chance in small populations. They finish by explaining how reproductive isolation produces new species and by reading cladograms built from shared derived characters.

  • 5 lessons
  • About 125 minutes
  • Evolution and evidence check: 12 questions
  • Ways to answer: fill in the blanks, choose an answer, highlight a text, match pairs, type a number and put in order
See plans Included with Family, Teacher and School plans. Open in PlayOwl

What learners will discover

  • Explain natural selection (variation, inheritance, overproduction and competition, differential survival and reproduction, time) and distinguish it from need-based explanations.
  • Evaluate fossil, anatomical, embryological, molecular and biogeographic evidence for common ancestry, including homologous, analogous and vestigial structures.
  • Calculate allele frequencies and their change over generations, and distinguish natural selection, genetic drift, gene flow and mutation as causes of change.
  • Explain speciation through reproductive isolation and read cladograms to compare relatedness using shared derived characters and common ancestors.

Lessons

  1. Natural selection: the mechanism 8 steps4 practiceabout 24 min
  2. Evidence for common ancestry 8 steps5 practiceabout 26 min
  3. Measuring evolution: allele frequencies 9 steps5 practiceabout 27 min
  4. How new species form 7 steps4 practiceabout 22 min
  5. Reading cladograms 8 steps5 practiceabout 24 min
  6. Evolution and evidence check 12 questions at the end

Keep exploring

More 9th grade science

Guide for grown-ups