What Sets Living Apart from Non-Living?
Use MRS GREN + D as your life-process checklist:
M — Movement
Animals move; plants also show movements (flower opening; climbers twining; Drosera trapping insects; Mimosa folding on touch).
R — Respiration
Humans breathe (lungs); plants exchange gases via stomata.
S — Sensitivity/Response
Thorn prick → withdraw; hot cup → pull back; Mimosa folds; some plants "sleep" at night.
G — Growth
Children outgrow clothes; plants add roots, shoots, leaves.
R — Reproduction
Organisms produce young ones/seeds (continuity of life).
E — Excretion
Sweat/urine in animals; tiny water droplets (guttation) in grasses/roses.
N — Nutrition
All living beings need food/energy; plants make food, animals eat plants/other animals.
+ D — Death
Life processes eventually stop; non-living doesn't have this.
💡 Warm-up (Table idea):
Make a 3-column list — Thing → Living/Non-living → Reason using MRS GREN + D. Cars move but do not grow/respire/excrete/reproduce → non-living.
Are Seeds Living? — Germination Conditions (Activity)
Set up four pots for ~15 days and observe:
A — No water, sunlight present
→ No germination (water missing).
B — Excess water, sunlight present
→ No/poor germination (waterlogged soil → no air).
C — Moist soil, dark
→ Germination occurs (air + water present).
D — Moist soil, sunlight present
→ Germination occurs (air + water present).
Conclusion:
Water + air are essential for germination; light isn't essential for bean seeds (species vary). After sprouting, light is needed for healthy growth.
Why? Water softens the seed coat and activates the embryo; air (oxygen) in soil spaces supports seed respiration.
Growth & Movement in Plants (Activity)
Upright + light all around:
Shoot grows up, root grows down.
Inverted seedling:
Shoot bends up, root bends down.
One-sided light:
Shoot bends toward light (phototropism); root continues down (positive geotropism).
Plant Growth & Movement Diagram
Life Cycle Case Studies
🌱 Bean Plant Life Cycle
Seed → Germination → Seedling → Mature Plant → Flower → Fruit → New Seeds
🦋 Butterfly Life Cycle
Egg → Larva (Caterpillar) → Pupa (Chrysalis) → Adult Butterfly
🐸 Frog Life Cycle
Egg → Tadpole → Froglet → Adult Frog
HOTS / Exam-Style Practice
- 1
A robot can move, respond to touch, and even "learn." Using MRS GREN + D, explain why it's still considered non-living.
- 2
Why do seeds need air for germination? What happens if soil is waterlogged?
- 3
Explain the difference between phototropism and geotropism with examples.
- 4
Design an experiment to test if temperature affects seed germination. What variables would you control?
- 5
Compare the life cycles of a plant and an animal. What are the similarities and differences?
Quick Recap
- Use MRS GREN + D to identify living things: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition, and Death.
- Seeds need water + air for germination; light is not essential initially but needed for healthy growth.
- Plants show phototropism (bend toward light) and geotropism (roots grow down, shoots grow up).
- All living things go through life cycles with different stages of growth and development.