Unit 07 · Plant Diversity & Classification
This unit organizes the whole kingdom. It walks the major plant groups in order of increasing complexity — bryophytes, seedless vascular plants, gymnosperms, and angiosperms — and the split between monocots and dicots; it covers taxonomy and binomial nomenclature, the phylogeny and cladistics that group plants by shared ancestry, and how to build and use a dichotomous key to name an unknown specimen. Mastery means you can place a plant in its group and key it out to a name, defending each choice.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Major plant groups | Cannot name the major plant groups. | Lists a few groups but cannot order them or state their traits. | Orders bryophytes, seedless vascular plants, gymnosperms, and angiosperms and names the key innovation of each — vascular tissue, seeds, and flowers. |
| Monocots vs. dicots | Cannot tell a monocot from a dicot. | Names one difference but applies it inconsistently. | Distinguishes monocots and dicots by leaf venation, flower parts, and root type in real specimens. |
| Taxonomy & binomial nomenclature | Cannot explain why a plant has a two-part scientific name. | Reads a binomial name but muddles genus, species, or the ranks. | Explains binomial nomenclature, writes a name correctly, and places a plant in the taxonomic hierarchy. |
| Phylogeny & cladistics | Treats classification as a random list. | Reads a simple tree but cannot infer relationships from it. | Uses shared derived traits to read a cladogram and explains how phylogeny reflects common ancestry. |
| Lab technique (dichotomous key) | Cannot follow a key’s paired choices. | Works a key but takes wrong branches or ignores the specimen’s traits. | Uses a dichotomous key to identify an unknown plant, justifying each couplet choice from the specimen in hand. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“Parallel veins and flower parts in threes told me it was a monocot; then I ran it through the key one couplet at a time — leaf shape, then margin, then venation — down to the genus. The binomial is genus first, capitalized, then the species, both italicized.”
“There are like mosses and trees and flowers. The scientific name is just Latin. I started the key but I kept guessing which branch to take.”
You demonstrate this unit through a dichotomous-key identification — keying real specimens out to a name and defending each couplet choice aloud, not a multiple-choice test. A criterion counts as mastered only when you can both work the key and justify the plant biology behind it. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.