Living and Non-living

Overview

Living and Non-living is a foundational topic in the Science portion of Bihar TET Paper II. It forms the conceptual base for understanding biology, ecology, and environmental studies. Questions typically test your ability to distinguish between living and non-living things, recall the defining characteristics of life, and apply basic classification systems.

This topic connects directly to other syllabus areas like ecosystems, plant life, and human body systems. Expect 2-4 questions that may appear straightforward but often contain tricky options involving borderline cases (viruses, seeds, fire). Mastering the characteristics of life and the five-kingdom classification system is essential for scoring well.

Key Concepts

• **Living things** possess life and carry out life processes; **non-living things** lack these processes. Some non-living things were once living (dead wood, leather) — these are called **formerly living** or **dead matter**.

• **MRS GREN** is a useful mnemonic for the seven characteristics of living things: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

• **Cells** are the basic structural and functional units of life. All living organisms are made of one or more cells (Cell Theory by Schleiden and Schwann).

• **Growth in living things** is internal and irreversible (increase in cell number/size), while non-living things may increase in size externally (crystals, mountains) but this is not true biological growth.

• **Metabolism** refers to all chemical reactions within an organism — includes anabolism (building up) and catabolism (breaking down).

• **Classification** is the systematic arrangement of organisms into groups based on similarities and differences. It helps in easy identification and study of organisms.

• **Five Kingdom Classification** (by R.H. Whittaker, 1969) divides all organisms into: Monera, Protista, Fungi, Plantae, and Animalia.

• **Viruses** are considered borderline cases — they show characteristics of living things only inside a host cell. Outside, they behave like non-living particles.

Key Facts

| Characteristic | Living Things | Non-living Things | |----------------|---------------|-------------------| | Cellular structure | Present | Absent | | Growth | Internal, by cell division | External accumulation only | | Reproduction | Produce offspring | Cannot reproduce | | Respiration | Release energy from food | No respiration | | Excretion | Remove metabolic wastes | No excretion | | Sensitivity | Respond to stimuli | No response | | Movement | Self-generated movement | Move only by external force | | Nutrition | Obtain and use food | No nutrition | | Definite lifespan | Yes — birth to death | No lifespan |