Lesson focus: cellThe basic unit of all living things; every organism is made of one or more cells. form tissueA group of similar cells working together to do a job, such as muscle tissue., tissues form organA body part made of different tissues working together to do a job, such as the heart or a leaf., and organs cooperate in organ systemA group of organs working together, such as the digestive system..
Explain levels of organisation using a complete heart-to-organism example.
Build on earlier learning
Specialised cellsRevisit specialised cells before grouping them into tissues and organs.
You will be successful when you can…
- Order five levels of organisation.
- Define tissue, organ and organ system precisely.
- Give a complete biological example.
- Explain cooperation between tissues in an organ.
Words that carry the science
- cell
- Basic structural and functional unit of an organism.
- tissue
- Group of cells working together for a function, often with more than one cell type.
- organ
- Structure made of different tissues working together.
- organ system
- Group of organs cooperating in major body functions.
- organism
- An individual living thing.
Build from specialised cells to a coordinated organism
01Hierarchy describes cooperation
Specialised cellThe basic unit of all living things; every organism is made of one or more cells. cooperate in a tissueA group of similar cells working together to do a job, such as muscle tissue.. Different tissueA group of similar cells working together to do a job, such as muscle tissue. combine into an organA body part made of different tissues working together to do a job, such as the heart or a leaf.; organA body part made of different tissues working together to do a job, such as the heart or a leaf. coordinate in an organ systemA group of organs working together, such as the digestive system.; systems form an organismA living thing, such as a plant, animal or bacterium..
The hierarchy is not only about size. Each level produces functions through interactions among its parts.
02The heart contains several tissues
Cardiac muscle tissue contracts, nervous tissue coordinates rate, connective tissue supports, and epithelial tissue lines surfaces. Together they form the heart.
The heart and blood vessels cooperate in the circulatory system to transport substances.
03Systems depend on one another
The circulatory system receives oxygen from the gas-exchange system and nutrients from the digestive system, then transports them to cells. Organisation is a network, not separate boxes.
Follow each link to make the biological reasoning explicit.
- Cardiac muscle cellSpecialised contracting cell.
- Cardiac muscle tissueCells coordinate contraction.
- HeartDifferent tissues pump blood.
- Circulatory systemHeart and vessels transport substances.
- Human organismSystems cooperate to sustain life.
Classify the heart
Why is the heart an organ rather than a tissue?
- Identify at least two tissues: cardiac muscle and connective/lining tissue.
- State that they perform different roles.
- Explain that they work together in one structure to pump blood.
- Conclude that a multi-tissue functional structure is an organ.
How to make the reasoning visible: Classification depends on composition and cooperation, not familiarity.
Hierarchy repair
Correct each incomplete or misplaced chain.
| Starting item | Next level | Complete route |
|---|---|---|
| Ciliated epithelial cell | Tissue | Trachea → respiratory system → human |
| Muscle cell | Muscle tissue | Biceps muscle → movement system → human |
| Palisade cell | Palisade tissue | Leaf → shoot system → plant |
| Cardiac muscle cell | Cardiac muscle tissue | Heart → circulatory system → human |
Why is the heart not made only of cardiac muscle tissue?
How can damage at cell level affect an organ system?
Use the table. Write the route from a muscle cell to the whole human.
Check your understanding
Answer from memory, then check against the suggested answer.
What is a tissue?
What is an organ?
What follows organ in the hierarchy?
Put these in order from smallest to largest: organ, cell, organism, tissue, organ system.
What is an organ system?
Classify a leaf and justify your answer.
Explain why studying one heart-cell type cannot fully explain heart function.
The stomach contains muscle tissue and lining tissue. Why does it need both?
Exam Question Practice
Exam Question Practice
Mark points shown after marking
Describe the relationship between a tissue, an organ and an organ system using the heart.
(4)Total for this question: 4 marks
Command word: For describeA command word: say what happens or what something is like, step by step, without needing to give reasons., give the ordered relationship and a concrete example.