Mississippi Science BIO.4.3

ScienceGrades 9–12Biology

The Standard

BIO.4: Students will analyze and interpret evidence to explain the unity and diversity of life.

Analyze cladograms/phylogenetic trees to illustrate relatedness between species.

2026 Mississippi College- and Career-Readiness Standards for Science · Adaptations and Evolution

Teacher's field guide

What Students Need to Do: Students trace branches backward to find where two species meet. They use that branch point to compare how closely species are related.
What Mastery Looks Like: Given a tree with frog, lizard, crocodile, and bird, a student identifies crocodile and bird as closest relatives. They can explain why moving the tips on the page does not change that relationship.
Common Misconceptions: Students may choose two species because their names sit next to each other, even when their branches meet farther back. They may also assume one living species descended from another living species on the tree.
How to Assess It: Draw a tree with frog branching first, lizard second, and crocodile and bird sharing the final fork. Ask: 'Is bird more closely related to crocodile or lizard? Circle the branch point that shows why.'

Lesson moves

Copy the four-species tree with yarn and labeled cards, then place a bead at each branching point.
Draw the tree twice, flipping the crocodile and bird tips in the second drawing; ask students whether their relationship changed.
Post the tree and have teams rank frog, lizard, and crocodile by how closely each is related to bird.
Show a printed influenza strain tree; have students circle two strains with a recent shared ancestor and explain why scientists track them.

Free download

A ready-to-print activity worksheet aligned to BIO.4.3, with an answer key for the teacher on its own page. No account needed.

PDF, US Letter, prints cleanly in black and white.

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