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Tissues - Why are Plant and Animal Tissues Different?

Grade 9CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Plants are stationary or fixed, so they require tissues that provide structural strength. Most of these tissues are supportive and consist of dead cells (e.g., sclerenchyma) because dead cells provide mechanical strength as easily as living ones and need less maintenance.

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Animals move around in search of food, mates, and shelter. They consume more energy compared to plants, meaning most of the tissues they contain are living tissues.

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The growth in plants is limited to certain regions (meristematic tissues), whereas growth in animals is more uniform. There is no such demarcation of dividing and non-dividing regions in animals.

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Structural organization of organs and organ systems is far more specialized and localized in complex animals than in even very large plants.

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The maintenance energy required by plants is low (Eplant<EanimalE_{plant} < E_{animal}) because they do not perform locomotion.

📐Formulae

Energy Requirement: EAnimal≫EPlant\text{Energy Requirement: } E_{Animal} \gg E_{Plant}

Plant Growth=∑Localized Meristematic Activity\text{Plant Growth} = \sum \text{Localized Meristematic Activity}

Animal Growth≈Uniform Cell Division across the Body\text{Animal Growth} \approx \text{Uniform Cell Division across the Body}

Dead Supportive TissuesTotal Tissues (Plants)>Dead Supportive TissuesTotal Tissues (Animals)\frac{\text{Dead Supportive Tissues}}{\text{Total Tissues}} \text{ (Plants)} > \frac{\text{Dead Supportive Tissues}}{\text{Total Tissues}} \text{ (Animals)}

💡Examples

Problem 1:

Calculate the theoretical energy difference factor if an animal uses 1000 J1000\text{ J} for locomotion and 500 J500\text{ J} for basic metabolism, while a stationary plant of similar biomass uses only 450 J450\text{ J} for metabolism.

Solution:

1000+5001500\begin{array}{r} 1000 \\ + 500 \\ \hline 1500 \end{array} Total Energy (Animal) = 1500 J1500\text{ J}. Total Energy (Plant) = 450 J450\text{ J}. Difference = 1500−450=1050 J1500 - 450 = 1050\text{ J}.

Explanation:

The animal requires significantly more energy (1500 J1500\text{ J}) compared to the plant (450 J450\text{ J}) because of the additional energy spent on movement (locomotion).

Problem 2:

Identify which tissue type (Living or Dead) is predominant in a tree trunk versus a human leg muscle.

Solution:

Tree trunk →\rightarrow Predominantly Dead tissues (Xylem/Sclerenchyma). Human leg muscle →\rightarrow Predominantly Living tissues (Muscular tissue).

Explanation:

The tree trunk provides mechanical support to a stationary object, hence utilizes dead cells to minimize energy cost. The human leg muscle facilitates movement, requiring active metabolism and living cells.