Avadhi and Aayush go for a morning walk with their parents. Avadhi notices some shells and tries to pick them up. Her mother advises her not to do so and explains that the shell could be home to a living snail and is actually a part of its body. Avadhi and Aayush wonder how the shell that is not even moving could have a living being inside! Later that day in school, they share this incident with their friends. They approach the teacher to understand how a shell which is not even moving could be a body part of a living snail. The teacher initiates a discussion in the class on living and non-living.
🔬 Activity 10.1: Let us record
- •We are surrounded by numerous things. Just look around in your classroom and you may find many examples—the pencil that you are holding, the book that you are reading or the pigeon near the window.
- •List them in Table 10.1 and identify each of them as living or non-living on the basis of your understanding in column II.
- •Write a reason for grouping them as living or non-living in column III.
- •After learning the characteristics of living beings, fill up the remaining two columns (IV and V) of Table 10.1.
Table 10.1: Living beings and non-living things in our surroundings
Loading saved data...
| Name | My guess (Living/Non-living) | Reason/Remarks | Correct answer | Reason/Remarks for correct answer |
|---|---|---|---|---|
| Pencil | Non-living | |||
| Book | ||||
| Pigeon | Living | |||
| Car | ||||
| Plant | ||||
| Any other |
10.1 What Sets the Living Apart from the Non-living?
Look at Table 10.1. Why do you think a pencil is non-living but a pigeon is living? What are the differences between living beings and non-living things according to you? Whenever you attempt to group things around you as living or non-living, you can compare them with yourself. A car does not grow — does it mean it is non-living? Which characteristics have you used to classify a car as non-living?
💡 Movement
Can we consider movement as one of the characteristics to differentiate between the living and the non-living? Unlike animals, plants do not move from one place to another, yet they are living. Plants show certain types of movements — opening of flowers, insectivorous plants (like Drosera) trapping insects with sticky hair-like projections, and climbers winding around objects. Even though plants do not move from one place to another, they do show some movements.
💡 Growth
Can you wear the dress that you used four years ago? No, because you have become larger in size due to growth. Plants and other living beings also grow. Growth is a characteristic of living beings.
💡 Nutrition
Living beings need food (nutrition) for their growth and development. List five living beings that require food to grow.
💡 Respiration
Breathing is part of a process called respiration. When we inhale, air moves from outside to inside our body; when we breathe out, air moves from inside to outside. Do plants also respire? Yes — tiny pores called stomata on the surface of leaves help plants take air in and out. All living beings respire.
💡 Excretion
Removal of waste products from the body is called excretion. Sweat consists of water and salts removed by the body as waste products. Urine is also a product of excretion in animals. Plants also excrete — they may excrete excess water and minerals in the form of small droplets on leaves (e.g., grasses and roses). All living beings excrete.
💡 Response to Stimuli
Any thing or any event that prompts living beings to respond is called a stimulus (plural: stimuli). Plants also respond to stimuli — for example, touch-me-not (Mimosa / chhui-mui / lajjalu) plants fold their leaves when touched. The sleeping leaves of amla (Indian gooseberry) fold after sunset. All living beings respond to stimuli.
💡 Reproduction
All living beings reproduce. Reproduction is the process of producing new ones of one's own kind. Reproduction is necessary for the continuity of life.
💡 Death
When a living being is not able to exhibit all of the above mentioned characteristics, despite the availability of all resources (like food, air and water) needed for being alive, it is said to be dead.
From the above discussion, we can understand that all living beings share some common characteristics: they show movement, need food, and they grow. They also respire, reproduce, excrete, respond to stimuli, and eventually die. Absence of any of these features indicates that they are non-living things.
10.2 Essential Conditions for Germination of a Seed
Have you observed a seed germinating? You might have wondered what conditions are required for germination of a seed. Let us investigate by performing Activity 10.2.
🔬 Activity 10.2: Let us experiment
- •Take four identical pots filled with garden soil. Sow four bean seeds in each pot. Keep these pots in the following conditions for 15 days:
- •Pot A: Do NOT water the soil. Place this pot in direct sunlight.
- •Pot B: Add excess water to the soil such that water is always present above the soil. Keep adding water regularly if water reduces. Place this pot in direct sunlight.
- •Pot C: Keep the soil slightly moist by adding a moderate amount of water regularly. Place this pot in a DARK location.
- •Pot D: Keep the soil slightly moist by adding a moderate amount of water regularly. Place this pot in direct sunlight.
- •Indicate the availability of air, sunlight and water for the seeds in each case in Table 10.2.
- •When a seed turns into a sprout, it is said to have germinated. Predict whether the seeds in each pot will germinate. Record your predictions and observations in Table 10.2.
- •Do your observations match with your predictions? Write possible reasons in Table 10.2. Based on your observations, state the conditions which favour seed germination.
Table 10.2: Effect of certain conditions on seed germination (Fig 10.1)
Loading saved data...
| Pot with bean seeds | Air | Sunlight | Water | Prediction | Observation | Possible reason |
|---|---|---|---|---|---|---|
| A: In direct sunlight and without water | No | |||||
| B: In direct sunlight and excess water | ||||||
| C: In complete dark and moist soil | ||||||
| D: In direct sunlight and moist soil |
💡 Conditions for Seed Germination
Water: Seeds require water for germination. Water softens the seed coat and helps the tiny embryo inside to develop into a plant.
Air and Soil: Seeds need air for germination. They use the air available in the spaces between soil particles. Spaces between soil particles also allow roots to grow easily.
Light and/or dark conditions: For bean seeds, light is not essential for germination. In general, most seeds do not require light for germination. But after germination, sunlight is required for further growth of the seedling.
Air and Soil: Seeds need air for germination. They use the air available in the spaces between soil particles. Spaces between soil particles also allow roots to grow easily.
Light and/or dark conditions: For bean seeds, light is not essential for germination. In general, most seeds do not require light for germination. But after germination, sunlight is required for further growth of the seedling.
🌟 Do you know?
Some seeds of flowering plants, like Coleus and Petunia, require light to germinate. Covering these seeds with soil inhibits their sprouting. Seeds of flowering plants, like Calendula and Zinnia, need darkness to germinate. These seeds should be covered with sufficient soil.
10.3 Growth and Movement in Plants
How do plants respond to sunlight? Does sunlight affect the direction of growth of different parts of plants? In which direction would the root and shoot of a plant grow if the plant is placed inverted? How would you design an activity to find answers to these questions?
🔬 Activity 10.3: Let us design
- •Take some bean or gram seeds and allow them to germinate on a moist cloth or moist tissue paper until each develops a small root and a small shoot.
- •Take three glass beakers or tumblers, and label them A, B and C.
- •Take three glass plates and attach thick blotting paper to one side using thick soft cotton thread.
- •Fix one seedling on each plate using soft cotton thread (ensuring the plant is not damaged).
- •Beaker A: Place plate upright with seedling — keep in direct sunlight from all directions.
- •Beaker B: Arrange the plate so that the shoot of the seedling is directed downwards and the root is directed upwards — keep in direct sunlight from all directions.
- •Beaker C: Place plate upright with seedling inside a cardboard box with a small circular hole — so sunlight reaches from one direction only.
- •Pour water in all three beakers to ensure the bottom of blotting paper soaks water (keeping seedling above water level).
- •Fill Table 10.3 with your predictions and observations. Do your predictions match your observations?
Table 10.3: Growth of root and shoot under different conditions (Fig. 10.2 & 10.3)
Loading saved data...
| Beaker | Direction of sunlight | Direction of plant | Shoot / Root | Predictions | Observations |
|---|---|---|---|---|---|
| A | All directions | Upright | Shoot | ||
| A | All directions | Upright | Root | ||
| B | All directions | Inverted | Shoot | ||
| B | All directions | Inverted | Root | ||
| C | Only from one direction | Upright | Shoot | ||
| C | Only from one direction | Upright | Root |
💡 Conclusions from Activity 10.3
1. When the plant is kept upright, the root grows downwards and the shoot grows upwards.
2. When the plant is kept inverted, the root bends and grows downwards. Also, the shoot bends and grows upwards.
3. When the plant gets sunlight only from one direction, the shoot grows in the direction of light while the root continues to grow downwards.
After conducting this activity, we can conclude that shoots of plants grow upward and exhibit movement towards sunlight, but roots of plants grow downwards.
2. When the plant is kept inverted, the root bends and grows downwards. Also, the shoot bends and grows upwards.
3. When the plant gets sunlight only from one direction, the shoot grows in the direction of light while the root continues to grow downwards.
After conducting this activity, we can conclude that shoots of plants grow upward and exhibit movement towards sunlight, but roots of plants grow downwards.
🔬
Jagadish Chandra Bose
1858–1937
Jagadish Chandra Bose was an Indian scientist who did some fascinating experiments with plants. He built a machine called a crescograph to record how plants respond to stimuli like light, heat, electricity and gravity. With this machine, he could measure how fast plants grow. He also showed that plants can sense and respond to stimuli.
10.4 Life Cycle of a Plant
We have learnt about conditions required for germination and how plants grow and exhibit movement. Let us now explore the changes a plant undergoes in its whole life.
🔬 Activity 10.4: Let us explore
- •Plant a bean seed and provide suitable conditions for its growth. Observe regularly for three months.
- •Record your observations in Table 10.4 as and when changes become visible.
- •Note the date when any change is observed. Record answers for: How long does it take for any change to occur? Make sketches of various changes in Table 10.4.
- •After how many days does the first flower appear?
- •After some parts of the flower have dried, can you see any further growth?
- •Which structure do the remaining parts of the flower develop into?
- •Can you notice a pod or a fruit with seeds develop from a flower?
- •What happens to the plant after the fruits containing seeds are formed?
Table 10.4: Changes observed during the growth of the plant
Loading saved data...
| Date | Observations | Sketches |
|---|---|---|
| Seeds are sown | ||
💡 Life Cycle of a Plant
A seed grows into a young plant and matures to produce flowers and fruit. The fruit contains seeds which give rise to a new generation of plants. The entire process from a seed to a plant, and then to the next generation of seeds is called the life cycle of a plant.
Stages: Seed → Seed germination → Appearance of leaves → Appearance of flowers → Appearance of fruits → Fruit/Pod with seeds → (back to) Seed, and eventually Death of plant.
When a plant stops growing and all activities of life gradually come to an end, even after the availability of all necessary conditions, the plant is considered dead.
Stages: Seed → Seed germination → Appearance of leaves → Appearance of flowers → Appearance of fruits → Fruit/Pod with seeds → (back to) Seed, and eventually Death of plant.
When a plant stops growing and all activities of life gradually come to an end, even after the availability of all necessary conditions, the plant is considered dead.
10.5 Life Cycle of Animals
We have learnt about the life cycle of a plant. Have you ever observed how animals grow over time? Animals go through many changes in their life cycle. Let us study the life cycles of a mosquito and a frog.
10.5.1 Life Cycle of a Mosquito
Mosquitoes buzzing around is a common experience. Female mosquitoes are bloodsucking insects that transmit several diseases like malaria, dengue and chikungunya. We are advised not to allow water to stagnate anywhere in our surroundings. Why is this so? Does stagnant water have any relation with mosquitoes laying eggs?
In stagnant water, you may find two different types of worm-like creatures: larva and pupa, two distinct life stages during the development of a mosquito (Fig. 10.5). Mosquito larvae and pupae live in water and require air to respire. They move to the surface of the water for air.
🌟 How can the life cycle of a mosquito be disrupted?
Kerosene oil, when sprayed on stagnant water, forms a thin layer over the water surface. This layer separates water from air, and does not allow larvae and pupae to inhale air. As a result, they die.
🔬 Activity 10.5: Let us analyse — Mosquito life cycle puzzle
- •How will you decide which stage (larva or pupa) comes immediately after the egg stage?
- •Suppose you are given a container with water from a puddle containing larvae and pupae. Design an activity to find out the correct sequence of these stages.
- •Avadhi's design: Step 1: Have a water container with mosquito larvae and pupae. Step 2: Separate 4–5 larvae and pupae into two separate containers with the same water. Step 3: Observe them every day until you see them changing to the next stage. Step 4: If the larvae change into pupae, it means the larval stage comes before the pupal stage, or vice versa. Step 5: Keep watching both containers to see in which one a mosquito appears first.
- •Without separating them from the container, how would you design an activity to decide which stage gives way to the next?
💡 Life Cycle of a Mosquito
Mosquitoes pass through four stages in their life cycle (Fig. 10.6):
Stage I — Egg: Adult female mosquito lays eggs directly on or near water.
Stage II — Larva: A worm-like creature that lives in water and comes to the surface to breathe.
Stage III — Pupa: A comma-shaped organism in water that also requires air to respire.
Stage IV — Adult mosquito: Emerges from the pupa and rests briefly on the water surface before flying away. May survive 10 to 15 days.
The adult female mosquito lays eggs near water, and the cycle continues. Significant changes occur in appearance, body shape and structure during the various stages.
Stage I — Egg: Adult female mosquito lays eggs directly on or near water.
Stage II — Larva: A worm-like creature that lives in water and comes to the surface to breathe.
Stage III — Pupa: A comma-shaped organism in water that also requires air to respire.
Stage IV — Adult mosquito: Emerges from the pupa and rests briefly on the water surface before flying away. May survive 10 to 15 days.
The adult female mosquito lays eggs near water, and the cycle continues. Significant changes occur in appearance, body shape and structure during the various stages.
🌟 Do you know?
The silk moth also passes through four life stages — egg, larva, pupa and adult. Eggs hatch into larvae, which then grow in size. Larvae secrete thread-like material which they wrap around themselves, before changing to pupae. These are the fibres used to make silk fabric. In India, the Khadi and Village Industries Commission (KVIC) has set up several centres for silk production.
10.5.2 Life Cycle of a Frog
🔬 Activity 10.6: Let us analyse — Frog life cycle
- •Go to a small water body during the rainy season with a facilitator. Take due safety precautions. Observe everything from a distance without causing disturbance.
- •You may notice a white jelly-like substance on the surface of water near the edge of the pond. This jelly-like substance is actually a cluster of eggs of a frog, known as spawn.
- •Observe the features of all stages of a frog shown in Fig. 10.7 (labeled A through F): • A: Cluster of eggs (spawn) floating near a lily pad • B: Young frog with a tail and four legs (froglet) • C: Small tadpole with a tail and no legs • D: Larger tadpole with a tail and two hind legs • E: Adult frog sitting on a lily pad • F: Another cluster of eggs (spawn)
- •How will you decide the sequence of the given stages (A, B, C, D, E, F)?
- •Record changes in Table 10.5. Based on observations, draw the life cycle of a frog and compare with Fig. 10.8.
- •Discuss: How are these frog eggs different from other eggs you may have seen? Which stage has the shortest duration? Is there a change in habitat during the various stages?
Table 10.5: Changes in different life stages of a frog (refer Fig. 10.7)
Loading saved data...
| Stage A | Stage B | Stage C | Stage D | Stage E | Stage F |
|---|---|---|---|---|---|
| Similar to C but has two legs. |
💡 Life Cycle of a Frog
You will find four stages in the life cycle of a frog (Fig. 10.8):
Stage I (A) — Spawn (Day 1): Adult frog lays a cluster of eggs (spawn) in water → Stage I (B) — Embryo (Day 3–4).
Stage II (A) — Tadpole with tail (Day 7–10): Hatches from egg; lives in water; tail helps it swim.
Stage II (B) — Tadpole with legs (8–10 weeks): Develops hind legs but still has tail.
Stage III — Froglet (12 weeks): Looks like a little frog; lives in water but begins to spend time on land. Tail begins to disappear.
Stage IV — Adult frog (14 weeks): Fully developed; lives both in water and on land; tail has disappeared completely; strong legs for jumping. Lays eggs and cycle continues.
Stage I (A) — Spawn (Day 1): Adult frog lays a cluster of eggs (spawn) in water → Stage I (B) — Embryo (Day 3–4).
Stage II (A) — Tadpole with tail (Day 7–10): Hatches from egg; lives in water; tail helps it swim.
Stage II (B) — Tadpole with legs (8–10 weeks): Develops hind legs but still has tail.
Stage III — Froglet (12 weeks): Looks like a little frog; lives in water but begins to spend time on land. Tail begins to disappear.
Stage IV — Adult frog (14 weeks): Fully developed; lives both in water and on land; tail has disappeared completely; strong legs for jumping. Lays eggs and cycle continues.
Plants and animals are a part of the living world. They go through various changes during the course of their lives. We have seen pupae change into insects, and tadpoles change into frogs. Such changes are important for plants and animals to survive and to maintain continuity of their kind. We should take care of them and their homes. By nurturing and preserving their homes, we contribute to this flourishing living world.
Keywords
Living▼
Non-living▼
Movement▼
Growth▼
Nutrition▼
Respiration▼
Breathing▼
Excretion▼
Stimulus▼
Response▼
Reproduction▼
Death▼
Germination▼
Life cycle▼
Larva▼
Pupa▼
Tadpole▼
Froglet▼
Conclude▼
Create▼
Design▼
Experiment▼
Explore▼
Identify▼
Observation▼
Prediction▼
📝 Summary (Key Points)
- 1The objects around us can be categorised into two types: living and non-living.
- 2The essential features of living beings are that they move, eat, grow, breathe, excrete, respond to stimuli, reproduce and die. Absence of any of these features indicates that they are not living beings.
- 3Each living being goes through several stages during its life.
- 4Germination of seeds depends upon the availability of water, air and suitable light and/or dark conditions.
- 5During germination of seeds, roots generally grow downwards, while shoots grow upwards.
- 6A plant's life cycle starts with seed germination, followed by several stages of growth and development, including flowering and seed production. Seeds produced during their life cycle germinate into new plants and the cycle continues.
- 7The life cycle of an animal begins with a new born that undergoes various stages of growth and development followed by an adult stage and finally death. The process of reproduction maintains the continuity of its kind.
- 8Mosquitoes pass through the stages of egg, larva, pupa and adult. The life stages of a frog include eggs, tadpoles, froglets and adults.
- 9In some living beings, such as mosquitoes and frogs, significant changes occur during the various stages of their life cycles. These changes can be seen in body shape, structure and sometimes even in the habitat.
📚 Let us enhance our learning
Loading your answers...
1
List the similarities and differences in life cycles of plants and animals.
2
Study the data and find examples appropriate for the conditions given below. If you think that an example for any condition is not possible, explain why.
1. Does NOT grow / Does NOT respire — Example: ___
2. Does NOT grow / Does respire — Example: ___
3. Does grow / Does NOT respire — Example: ___
4. Does grow / Does respire — Example: ___
3
You have learnt that different conditions are required for seed germination. How can we use this knowledge for proper storage of grains and pulses?
4
You have learnt that a tail is present in a tadpole but it disappears as it grows into a frog. What is the advantage of having a tail in the tadpole stage?
5
Charan says that a wooden log is non-living as it cannot move. Charu counters it by saying that it is living because it is made of wood obtained from trees. Give your arguments in favour or against the two statements given by Charan and Charu.
6
What are the similarities and distinguishing features in the life cycles of a mosquito and a frog?
7
A plant is provided with all the conditions suitable for its growth (Fig. 10.9 — pot kept along the ground horizontally). Draw what you expect to see in the shoot and the root of the plant after one week. Write down the reasons.
8
Tara and Vijay set up the experiment shown in Fig. 10.10 (a seed planted horizontally, shoot curving upward, root going downward). What do you think they want to find out? How will they know if they are correct?
9
Design an experiment to check if temperature has an effect on seed germination.
🚀 Learning Further
- Make a field trip to a local garden. Interact with a gardener to learn about various conditions and the time required for the growth of various plants.
- Can we grow plants without germinating their seeds? Explore and cite some examples.
- Observe the life cycle of five plants grown at home, school, or in a nearby garden. Create a picture book containing pictures of various stages of their growth. Write the name of each plant and the duration of each of its stages.
- Try to observe some of the stages in the life cycle of a butterfly or a moth. Are these stages similar to the stages in the life cycle of a mosquito?
- In your opinion, would the environment affect the life cycles of insects? Explore and list the factors that affect the life cycles of insects.
- Let us create: Add more lines to the incomplete poem about frogs — "In shaded and grassy bogs, / There lived a group of frogs. / They happily sang from dusk to dawn, / In double bass going on and on. / One day sitting beside a reed, / Female frogs think it's time to breed..." Include information on the different stages in development of a frog.
