Mississippi Science MAQ.5.4

ScienceGrades 9–12Marine and Aquatic Science I & II

The Standard

MAQ.5: Students will explore the biodiversity and interactions among aquatic life.

Use dichotomous keys to identify sample producers within an aquatic ecosystem.

2026 Mississippi College- and Career-Readiness Standards for Science · Primary Producers

Teacher's field guide

What Students Need to Do: Students examine aquatic producers or their photos and follow paired choices in a dichotomous key. They name each sample and point to the trait behind each choice.
What Mastery Looks Like: A student can use a key to identify an unfamiliar producer without skipping steps. They record visible evidence, such as floating leaves or rock-attached blades, for each choice.
Common Misconceptions: Students may guess from color or skip steps when a sample looks familiar. They may mistake kelp blades for true leaves or assume every floating plant is algae.
How to Assess It: Show photos of a diatom, duckweed, and kelp with this key: single cell, diatom; many cells, check for floating leaves (duckweed) or rock-attached blades (kelp). Ask students to label all three and record each choice.

Lesson moves

Give pairs laminated photos of duckweed, kelp, and diatoms; have them sort by visible traits, then use a printed key to name each.
Show a kelp photo and ask, "Which visible trait rules out duckweed at the next split, and why?"
Play key relay: teams identify four producer photos, marking each numbered choice before passing the key to the next teammate.
Give students a lake monitoring sheet with photos of duckweed and filamentous algae; have them identify each sample before recording its name.

Free download

A ready-to-print activity worksheet aligned to MAQ.5.4, 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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