Unit 03 · From Cells to Organisms
Your body is a team of trillions of cells working together. This unit follows the ladder of life — cells build tissues, tissues build organs, and organs build the systems that keep you alive. You’ll explore the major body systems, like the digestive, circulatory, respiratory, and nervous systems, and see how they team up. Mastery means you can explain how a part’s shape fits its job and how the systems work together.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Levels of organization | Thinks the body is just one big lump of cells. | Lists cells, tissues, and organs but mixes up the order. | Puts the levels in order — cells → tissues → organs → organ systems → organism — with an example of each. |
| Major body systems | Can name only one or two body systems. | Names several systems but not what each one does. | Names the major systems — digestive, circulatory, respiratory, skeletal, muscular, nervous — and explains the main job of each. |
| How systems work together | Treats each body system as if it works alone. | Knows systems connect but can’t trace one example. | Traces how two or more systems team up — like how the lungs and blood deliver oxygen to your cells. |
| Structure fits function | Doesn’t link a body part’s shape to its job. | Notices a shape but can’t explain why it helps. | Explains how a part’s structure fits its function — like why lungs are spongy or bones are hollow. |
| Lab technique (body-system modeling) | Builds a model that leaves out key parts or connections. | Builds a model but can’t explain how the parts link up. | Builds a clear model of a body system and uses it to explain how the parts work together. |
| 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. |
“When I breathe in, my lungs take in oxygen, and my heart pumps blood to carry that oxygen to every cell. The lungs are spongy so they have lots of room to trade gases. It’s two systems — respiratory and circulatory — working as a team.”
“The heart pumps blood and the lungs are for breathing. I’m not sure how they’re connected. A tissue is kind of like an organ, right?”
You demonstrate this unit by building and explaining models of the body systems — showing how cells build up to whole systems and how those systems work together — aloud, not on a multiple-choice test. A criterion counts as mastered only when you can both build the model and explain the biology it shows. 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.