An organ is made of several different tissues working together. A leaf has epidermis, palisade and spongy mesophyll and vascular tissue; the heart has cardiac muscle, a lining, connective tissue and nervous tissue.
A leaf looks like one green sheet. Slice it thinly and look through a microscope, and you find at least five different layers, each doing a different job.
Cells specialise; similar cells form tissues. This lesson: tissues build organs.
Engage: Commit to a prediction before you test anything. A wrong guess is fine: it shows you what to look for.
Explore: Try it on the board and compare what happens with your prediction.
Explain: Use the particle model to explain what you saw.
Elaborate: Use the same idea in a new context.
Evaluate: Look back at your first ideas and what changed.
WidthMore contexts, same idea.
Make your prediction first. Help opens once you've locked it in.
EngageCommit to a prediction before you test anything. A wrong guess is fine: it shows you what to look for.
Engage: one tissue or many?
ExploreTry it on the board and compare what happens with your prediction.
Explore: inside a leaf
Try it yourselfYour edits are saved in this browser.
Find every tissue in the leaf section.
Use the board. This ticks when you get there.
ExplainUse the particle model to explain what you saw.
Explain: tissues working together
In your book: choose the leaf or the heart, name two of its tissues and explain how each helps the organ work.
Match each leaf tissue to its job.
Palisade mesophyll
Spongy mesophyll
Xylem
Phloem
Epidermis
Put the levels of organisation in order, smallest first.
Pieces (click to add)
Your program
Elaborate TypicalUse the same idea in a new context.
Elaborate: the heart wall
Try it yourselfYour edits are saved in this browser.
Find every tissue in the heart wall.
Use the board. This ticks when you get there.
Elaborate WiderUse the same idea in a new context.
Elaborate: when a tissue fails
EvaluateLook back at your first ideas and what changed.
Evaluate: look back
Write one sentence: "At first I thought… Now I think… because…"
Revision summary
Cells → tissues → organs → organ systems → organism.
A tissue is a group of similar cells doing one job; an organ is several tissues working together.
A leaf: epidermis, palisade and spongy mesophyll, xylem and phloem. The heart: cardiac muscle, lining, connective tissue, nervous tissue.
No single tissue can do everything an organ needs.
For teachers
Students describe an organ as several tissue types working together and explain each tissue's contribution (AC9S8U02, node 3, a hinge node). About 25 minutes.
I can name two tissues in an organ and explain how each helps.
I can explain why organs need more than one tissue.
I can put cells, tissues, organs, systems and organisms in order.
Before class
A concept tutorial for introducing or revising the idea; it does not replace a leaf section under the microscope or a heart dissection. Set the width with ?width=minimum, typical (default) or wider.
The hinge risk is organs as one tissue ("the heart is a muscle"). The leaf shows five tissues before the heart appears.
Board notes: the leaf is one simplified slice; the heart diagram is a strip of the wall, not the whole heart.
Running the lesson
Engage: 'one kind of green cell' is the misconception to resolve.
Explore: ask which tissue does photosynthesis and which brings water.
Explain: the 'why several' question is the checkpoint.
The hard part (on purpose)
Seeing an organ as several tissues working together. When a student says the heart is just muscle, ask what else it needs to do its job.
When students get stuck
A student says the heart is just muscle. Ask: What stops the blood flowing backwards? Fix: Valves, made of connective tissue: a different tissue.
A student mixes up tissue and organ. Ask: Is it one kind of cell, or several kinds working together? Fix: One kind: tissue. Several tissues: organ.
Stretch and support
Stretch: The skin is your largest organ. Name three tissues it might contain.
Support: Give the levels ladder (cell → organism) as a card.
Where it leads
Next: organ systems (node 4).
In class: leaf sections under the microscope; a sheep heart dissection.
What each step is for
Engage: one tissue or many?: Students who see an organ as one tissue ('the heart is muscle') will choose that; the leaf section shows several tissues.
Explore: inside a leaf: Clicking each tissue in the section shows how many jobs one organ needs.
Explain: tissues working together: Explaining why one tissue couldn't do an organ's whole job is the hinge to organ systems.
Elaborate: the heart wall: A second organ, an animal one, shows the same multi-tissue pattern.
Elaborate: when a tissue fails: Tracing a tissue disorder to organ failure shows why organ function depends on every tissue.
Now you can
Name two tissues in an organ and explain how each helps.
Explain why organs need more than one tissue.
Put cells, tissues, organs, systems and organisms in order.