Levels of organization – from cell to organism
Integrated ScienceCells & OrganismsAges 11–12
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Cells & Organisms
Drag the zoom slider (or click each level) to move from cell → tissue → organ → organ system → organism in humans (cardiac muscle cell → cardiac muscle tissue → heart → circulatory system → body) and in a plant (mesophyll cell → mesophyll tissue → leaf → shoot system → whole plant). Each level shows a smoothly transitioning illustration with its name and role, and autoplay steps through the whole sequence. A Surface area to volume mode models a cell as a cube of side a: change a and the number of parts per side k to see SA:V = 6/a fall as a cell grows and rise when the same volume is split into many small cells.
Lesson: Levels of organization in a multicellular organism: cell, tissue, organ, organ system, organism
What it shows
In a multicellular organism, cells of the same type group into tissues, different tissues work together in organs, organs cooperate in organ systems, and organ systems make up the whole organism. The simulation follows this hierarchy in a human (cardiac muscle cell, cardiac tissue, heart, circulatory system, human body) and in a tomato plant (mesophyll cell, parenchyma tissue, leaf, shoot system, whole plant). Each level is built from the one below and can do things its parts cannot do alone: the heart pumps blood only because several tissues act together. In the Surface area to volume mode a cell is a cube of side a, with surface area SA = 6a², volume V = a³ and SA:V = 6/a; splitting the same volume into k³ smaller cubes multiplies the total surface by k. Cells exchange materials through their surface but use them in their whole volume, one reason large organisms are built from many small cells.
How to use
Let Autoplay run through the levels once, then press Pause and use the level buttons or the Zoom out slider to stop at each level. Ask students to name the level, describe its role and suggest another example before reading the caption. Then set Organism to the tomato plant and compare the two sequences, paying special attention to the difference between a tissue and an organ. Then press Surface area to volume, increase Cell side a and watch SA:V fall on the graph; raise Parts per side k to split the cell, and press Record to compare the results in the table.
Parameters you can change
- Organism Human (circulatory system), Tomato plant (shoot system)
- Starting level Cell, Tissue, Organ, Organ system, Organism
- Autoplay through the levels
- Autoplay speed 0.2–2 levels/s
- Mode Levels of organization, Surface area to volume
- Cell side a (surface area to volume mode) 2–100 µm
- Parts per side k (splits into k³ cells) 1–5
Questions to explore
- Why is the heart an organ while cardiac muscle is a tissue?
- Which organ system of the plant does a leaf belong to?
- If one level of organization is damaged, how are the levels above it affected?
