Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Biology
Lesson Topic: Explain that the sequences of bases in DNA are used as a means of classification.
Learning Objective/s:
  • Describe why classification is essential in biology.
  • Explain how DNA base sequences function as molecular barcodes for classification.
  • Compare traditional morphological classification with DNA‑based classification.
  • Interpret phylogenetic trees derived from DNA sequence data.
  • Evaluate the advantages and limitations of DNA sequencing in taxonomy.
Materials Needed:
  • Projector and screen
  • PowerPoint slides with diagrams
  • Handout summarising DNA barcoding steps
  • Sample DNA sequence worksheets
  • Computers with internet access to GenBank/BLAST
  • Whiteboard and markers
 Introduction:
Begin with a quick poll: “If you could identify any organism by a single code, what would it be?” Connect this to prior learning about traditional classification and explain that today students will discover how DNA sequences act as molecular barcodes. State that by the end of the lesson they will be able to describe the process and its implications.
Lesson Structure:
  1. Do‑now (5’) – Match common organisms to their traditional taxonomic ranks on a worksheet.
  2. Mini‑lecture (10’) – Present DNA as a molecular barcode, show a base‑sequence example and contrast with morphology‑based classification.
  3. Guided activity (15’) – Walk through the five steps of DNA barcoding (extraction to phylogenetic analysis) using a flowchart; students label each step on handouts.
  4. Group simulation (15’) – Using computers, retrieve a sample COI sequence from GenBank and perform a quick BLAST search to find a match.
  5. Class discussion (10’) – Interpret BLAST results, construct a simple phylogenetic tree, and discuss advantages and limitations.
  6. Check for understanding (5’) – Exit ticket: write one benefit and one limitation of DNA‑based classification.
Conclusion:
Summarise that DNA sequences provide a universal, objective way to classify life, complementing traditional methods. Students submit an exit ticket summarising one advantage and one limitation, and for homework they will read a short article on DNA barcoding applications and prepare a one‑paragraph reflection.