1. Chapter at a Glance
A puppy plays and grows; a toy car moves only when pushed. A seed lies still for months, yet sprouts when watered. What makes something living? This chapter lists the features shared by all living beings, explores how seeds germinate and how plants grow and move, and follows the life cycles of a plant, a mosquito and a frog.
- Characteristics of living beings: movement, nutrition, growth, respiration, excretion, response to stimuli, reproduction and death.
- Conditions needed for seed germination.
- Growth and movement in plants — shoots towards light, roots downwards.
- Life cycle of a plant, a mosquito and a frog.
2. What Sets the Living Apart from the Non-living?
| Characteristic | Meaning | Example |
|---|---|---|
| Movement | Living beings move on their own or move parts of their body | Animals walk; flowers open; Mimosa (touch-me-not) leaves fold |
| Nutrition | Need food for energy and growth | Plants make food; animals eat |
| Growth | Increase in size | A seedling becomes a tree; a baby becomes an adult |
| Respiration | Using air; includes breathing (air moving in and out) | Humans breathe; plants exchange gases through tiny pores called stomata |
| Excretion | Removal of waste products from the body | Sweat, urine; plants remove some wastes |
| Response to stimuli | Reacting to changes around | Pulling hand from a hot object; Mimosa folding when touched |
| Reproduction | Producing young ones of their own kind | Seeds, eggs, babies |
| Death | Every living being has a limited life span | Old plants and animals die |
A stimulus is anything or any event that makes a living being respond. Insect-eating plants like Drosera respond to insects; leaves of Mimosa pudica and amla fold at night or on touch. A non-living thing does not show these features on its own. A living being is called dead when it can no longer show the characteristics of life even when resources are available.
A dry seed does not seem to eat or grow, yet given water and air it germinates and grows. So it is living but inactive (dormant). A wooden log comes from a once-living tree, but it cannot grow or reproduce now — it is no longer living.
3. Essential Conditions for Germination
Germination is the process in which a seed sprouts into a young plant. An experiment with four pots of bean seeds — (A) with water and air, (B) dry, (C) water and air but kept in the dark, (D) fully under water (no air) — shows:
| Pot | Water | Air | Light | Germinates? |
|---|---|---|---|---|
| A | Yes | Yes | Yes | Yes |
| B | No | Yes | Yes | No |
| C | Yes | Yes | No | Yes |
| D | Yes (submerged) | No | Yes | No |
Conclusion: seeds need the right amount of water and air to germinate; most seeds do not need light. (Some seeds, such as Coleus and Petunia, germinate better in light, while Calendula and Zinnia prefer darkness.) Suitable temperature also matters. This is why grains are stored dry — so that they do not sprout or spoil.
4. Growth and Movement in Plants
If a seedling is kept upright in light from all sides, its shoot grows up and root grows down. If light comes from only one side, the shoot bends towards the light. Even if a pot is turned upside down, roots turn to grow downwards and shoots turn upwards. So:
- Shoots grow upwards and towards sunlight.
- Roots grow downwards (towards the Earth and water).
Scientist Jagadish Chandra Bose invented sensitive instruments (such as the crescograph) and showed that plants respond to stimuli like touch, light and temperature, much like animals do.
5. Life Cycle of a Plant
A bean seed germinates → seedling → young plant with leaves → flowers → fruits (pods) with seeds → seeds grow into new plants; the old plant eventually dies. The entire process from seed to adult and back to seed is the life cycle.
6. Life Cycles of Animals
Mosquito — four stages
Egg → larva → pupa → adult. Eggs are laid in stagnant water. Larvae (wrigglers) and pupae live in water but breathe air at the surface. Spreading a thin layer of oil on stagnant water blocks their air and kills them — this helps control diseases like malaria and dengue.
Frog — four stages
Eggs (spawn) → tadpole → froglet → adult frog. A frog lays a jelly-like mass of eggs called spawn in water. A tadpole hatches; it has a tail for swimming and breathes in water. Hind legs, then front legs grow, the tail shrinks, and it becomes a froglet that spends time on land. Finally it becomes an adult frog.
| Feature | Mosquito | Frog |
|---|---|---|
| Number of stages | Four | Four |
| Young stage | Larva, pupa (in water) | Tadpole (in water) |
| Adult habitat | Air / land | Water and land |
| Young looks like adult? | No | No |
7. Master Table: Key Terms
| Term | Meaning |
|---|---|
| Stimulus | Anything that makes a living being respond |
| Respiration | Use of air; includes breathing |
| Excretion | Removal of wastes from the body |
| Reproduction | Producing new ones of the same kind |
| Germination | Seed sprouting into a young plant |
| Life cycle | Stages from birth to adult and the next generation |
| Larva / Pupa | Young stages of a mosquito |
| Spawn / Tadpole / Froglet | Egg mass / tailed young / young frog of a frog |
8. Master Summary Table
| Topic | Key fact | Exam point |
|---|---|---|
| Living features | Eight characteristics | Seed is living but dormant |
| Germination | Needs water and air | Light usually not needed |
| Plant growth | Shoot to light, root down | Predict growth in experiments |
| Mosquito | Egg, larva, pupa, adult | Oil on water kills larvae |
| Frog | Spawn, tadpole, froglet, adult | Tail helps tadpole swim |
9. Mind Map
- Move, eat, grow, breathe
- Excrete, respond, reproduce, die
- Water + air
- Store grains dry
- Shoot → light
- Root → down
- Plant: seed to seed
- Mosquito, frog: 4 stages
10. Tips and Tricks
- Remember living features with “MR GREEN D”: Movement, Respiration, Growth, Response, Excretion, Eating (nutrition), Newborn (reproduction), Death.
- Mosquito stages: “E-L-P-A” (Egg, Larva, Pupa, Adult).
- In germination experiments, change only one condition at a time.
- Saying “a car moves, so it is living” — it does not grow, breathe or reproduce.
- Thinking seeds need sunlight to germinate — most do not.
- Writing that tadpoles breathe air like adult frogs — tadpoles live and breathe in water.
11. Important One-liners
- All living beings need food, grow, respire, excrete, respond, reproduce and die.
- Plants exchange gases through stomata.
- Mimosa pudica leaves fold when touched.
- Seeds need water and air for germination.
- Shoots grow towards light; roots grow downwards.
- Mosquito life cycle: egg, larva, pupa, adult.
- A jelly-like cluster of frog eggs is called spawn.
- A tadpole has a tail and lives in water.
- J. C. Bose showed that plants respond to stimuli.
12. Exam-pattern Questions with Detailed Answers
Which of these is NOT a characteristic of living things?
- Growth
- Reproduction
- Rusting
- Respiration
Show answer
Rusting happens to iron, a non-living thing. The others are features of life.
Answer: (C) Rusting
Name the four stages of a mosquito’s life cycle.
Show answer
Egg, larva, pupa and adult.
Answer: Egg → larva → pupa → adult
What is a stimulus? Give an example.
Show answer
Anything that makes a living being respond. Example: touching a Mimosa leaf makes it fold.
Answer: A change that causes a response, e.g. touch
Why are grains stored in dry places?
Show answer
Seeds need water to germinate. In dry places they cannot absorb water, so they do not sprout or rot and stay usable for long.
Answer: Without water they cannot germinate or spoil
In an experiment, seeds kept completely under water did not germinate. Why?
Show answer
Seeds under water get no air. Air is essential for germination, so they fail to sprout.
Answer: Lack of air
How does a tail help a tadpole?
Show answer
The tadpole lives in water. Its tail helps it swim to find food and escape from enemies. The tail disappears when it becomes a frog that lives partly on land.
Answer: Helps it swim in water
Write two similarities and two differences between the life cycles of a mosquito and a frog.
Show answer
Similarities: both have four stages; early stages live in water. Differences: mosquito stages are larva and pupa, frog’s are tadpole and froglet; adult mosquito flies in air, adult frog lives in water and on land.
Answer: Four stages, water-dwelling young; different stages and adult habitats
A seedling is placed near a window. What will happen to its shoot after a few days?
Show answer
The shoot will bend towards the window because shoots grow towards light.
Answer: It bends towards the light
Design an experiment to check whether temperature affects germination of seeds.
Show answer
Take three sets of equal bean seeds on wet cotton with air. Keep one set in a refrigerator (cold), one at room temperature and one in a warm place. Keep water and air the same. Observe for a week. Compare how many seeds germinate in each set to see the effect of temperature.
Answer: Same seeds, water, air; vary only temperature
Pinky says a wooden log is living because it came from a tree. Rahul says it is non-living. Who is right?
Show answer
Rahul. The log was part of a living tree, but now it cannot grow, respire, take food or reproduce. It no longer shows the characteristics of life, so it is non-living (dead).
Answer: Rahul — the log shows no life features now
How does spreading kerosene or oil on stagnant water help control malaria?
Show answer
Mosquito larvae and pupae live in water but take air from the surface. A thin oil layer cuts off their air supply, so they die before becoming adults, reducing mosquitoes that spread malaria.
Answer: Oil blocks air to larvae and pupae
A plant pot is placed on its side. Predict the direction of growth of root and shoot after a week.
Show answer
The shoot will curve upwards (and towards light) and the root will curve downwards, because shoots grow up and roots grow down regardless of how the pot is placed.
Answer: Shoot bends up, root bends down
13. Quick Revision Summary
- Living beings move, need food, grow, respire, excrete, respond to stimuli, reproduce and die.
- Seeds need water and air (not usually light) to germinate; grains are stored dry.
- Shoots grow towards light; roots grow downwards.
- Plant life cycle: seed → seedling → plant → flower → fruit → seed.
- Mosquito: egg → larva → pupa → adult; frog: spawn → tadpole → froglet → adult.