Tissues in Action · Lesson 1 of 11
Why are Plant and Animal Tissues Different?
“Plants stand still, animals wander off, and their tissues quietly reveal why.”
• Explain how cells are organised into tissues, organs and organ systems. • Describe division of labour in a multicellular organism. • Compare the basic needs of plant and animal bodies. • Relate differences in plant and animal tissues to movement, support, nutrition and growth.
Introduction
Imagine watching a seed become a tree and a single fertilised cell become an animal. In both cases, one cell divides repeatedly until millions of cells are present. Yet the finished organism is not simply a heap of identical cells. Some cells form protective coverings, some transport materials, some produce movement and some carry messages. The remarkable part is not only that the cells multiply, but that they organise themselves into cooperating groups.
A single-celled organism must perform every life process within one cell. It must obtain food, exchange gases, remove wastes, respond to changes and reproduce. In a multicellular organism, different groups of cells become specialised. This sharing of work makes it possible to perform many complex processes efficiently and at the same time.
Tissue
A tissue is a group of cells, similar in structure, that work together to perform a specific function.
Cells performing a similar job form a tissue. More than one kind of tissue can then combine to form an organ. Different organs work together as an organ system, and the organ systems together form an organism. For example, muscular tissue produces force, nervous tissue provides instructions and connective tissue binds parts together. Movement becomes possible only when these tissues cooperate.
Problem
What happens when you pick up a glass of water?
- 1.The eyes provide information about the glass and its position.
- 2.Nervous tissue carries instructions from the brain to the arm.
- 3.Muscular tissue contracts and pulls the bones.
- 4.Connective tissues hold the moving parts together.
- 5.Several organs and tissues therefore complete one apparently simple action.
Most plants remain fixed in one place. They must resist gravity, wind and their own weight without walking to a new location. Their cells possess a rigid cell wall, and many plant tissues are specialised for support. Animals generally move from place to place. Their cells do not have rigid cell walls, so they can change shape more readily. This flexibility contributes to tissues that contract, bend and coordinate locomotion.
Nutrition creates another difference. Animals obtain food from other sources, so they need tissues for taking in food, digesting it, absorbing useful substances and transporting them through the body. Green plants make food using solar energy. They require tissues that expose leaves to light, absorb water and minerals through roots, and transport water and prepared food over long distances.
Growth also follows different patterns. Plants retain regions where cells continue dividing, allowing roots and shoots to lengthen and stems to thicken. In animals, growth is usually more widely distributed when the body is young and becomes limited in many tissues later. These different lifestyles explain why plant and animal tissues are organised differently.
| Feature | Plants | Animals |
|---|---|---|
| Movement | Most remain fixed in one place. | Most can move from place to place. |
| Cell boundary | A cell wall provides rigidity. | No cell wall; cells can change shape more easily. |
| Nutrition | Food is synthesised in green parts. | Food is obtained and digested. |
| Major needs | Support, absorption, photosynthesis and transport. | Movement, rapid coordination, digestion and transport. |
| Growth pattern | Certain regions keep dividing. | Growth is generally more widespread when young. |
A tissue is not the same as an organ. A tissue is a cooperating group of similar cells; an organ contains more than one tissue working together.
Quiz
Which description best matches Tissue?
Which term matches this description: A tissue is a group of cells, similar in structure, that work together to perform a specific function.
Which statement is a key takeaway from this lesson?
Which additional statement is also a key takeaway from this lesson?
Which further statement is also a key takeaway from this lesson?
Practice Problems
- Arrange these from simplest to most complex: organ system, cell, organism, tissue and organ.
- Explain why division of labour is useful in a multicellular organism.
- Why do plants generally require a greater amount of supporting tissue than animals?
- Connect the absence of a rigid cell wall in animal cells with locomotion.
- Give one example showing that several tissues must cooperate to perform a single action.
Key Takeaways
• Similar cells working together form a tissue. • Tissues form organs, organs form organ systems, and organ systems form an organism. • Division of labour increases efficiency. • Plant and animal tissues differ because the organisms differ in movement, nutrition, support and growth.
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Next · Lesson 2
Tissues for Growth in Plants