🧩 Chapter 2 — The Inter-relationships between Living Things
Full notes with definitions, examples & complete exercise answers — designed for a smooth, full-length reading experience on any device.
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1) 🌍 Big Idea & Key Definitions
All living things depend on their surroundings and on each other to meet basic needs such as food, water, air, shelter and safety. The way we obtain these needs and the places where those needs are fulfilled create strong inter-relationships among plants, animals and people.
🔤 Core Terms
- Environment — everything around us: living (plants, animals, people) and non-living (air, water, soil, sunlight, temperature).
- Need — anything required to live and grow (food, water, air, shelter, space).
- Habitat — the natural place where an organism lives and gets all its needs.
- Adaptation — a feature or behaviour that helps an organism survive in its habitat.
- Inter-dependence — living things relying on one another (e.g., birds eat insects; plants need animals for seed dispersal).
🧩 Riddle in the chapter
“An age-old tree with a thick trunk … like an old man’s beard with many strands … ropes for swinging…” 👉 Answer: the Banyan tree (with its hanging prop-roots). 🌳
2) 🧪 Needs of Living Things & Their Environment
Every living thing needs food 🍽️, water 💧, air 🌬️, and shelter 🏠. The environment supplies these, but the quantity and type needed is different for different organisms. For example, a mouse drinks a little water; an elephant needs a lot. A butterfly drinks flower nectar; a sheep eats leaves; a fish breathes in water through gills, but a pigeon cannot do that.
🌾 Simple experiment: Too much water = trouble
- Take two small boxes with moist soil; sow sprouted matki (moth) seeds in each.
- Box 1: give 2 spoons water once a day. Box 2: give 4 spoons water four times a day (water-logged).
- Observe for 6 days.
Result: Plants in Box 1 grow well 🌱; plants in Box 2 begin to rot 🥀.
Conclusion: Most land plants cannot live in marshy areas; if roots get more water than needed, they don’t get air and rot. Right place, right amount
Rule of thumb: “Any living thing will be found only where all its needs are met.”
3) 🐅 Where Organisms Live (Habitats) — Tiger Case Study
🎯 Tiger’s needs & adaptations
- Food: deer, nilgai, bison in grasslands/forests.
- Camouflage: stripes help it hide among tall grasses.
- Water: needs a nearby waterhole that doesn’t dry up in summer.
- Shelter: dense vegetation, tall grasses, caves or rocky hills.
Therefore: a tiger inhabits places where all these are present together — healthy forests/grasslands with prey, water and cover.
🫱🏽🫲🏼 Inter-dependence examples
- Butterflies need flower nectar; flowers get pollination in return 🦋🌸.
- Bulrushes grow in water; lemon trees cannot — different needs → different habitats.
- Fish breathe in water; cannot live on land. Frogs manage both for parts of their life.
4) 🪴 How Plants & Animals Help Us (and Each Other)
🐾 Animals are our friends
- Give milk, meat, eggs, wool and help in farm work. Dogs guard homes; bullocks/horse draw carts.
- Even dung is useful: dung-cakes as fuel, gobar gas 🔥, plastering mud houses, and rich manure for crops.
- We must care for them — feed, provide shelter and treatment. Animals show affection too. 💚
🌿 Plants serve us abundantly
- Food: grains, vegetables, fruits; leaves of many plants are used (betelvine, fenugreek, curry leaves, etc.).
- Materials: cotton for clothes, wood, medicines, flowers for many uses.
- We cultivate useful plants: sow seeds, water them, add manure, and spray pesticides to protect from insects.
🤝 Everyday inter-dependence
- Egret on buffalo’s back: buffalo scares insects out of grass; egret quickly eats them — both benefit (easy food for egret; fewer insects irritating buffalo).
- Silk comes from silkworms raised on mulberry leaves.
- Termites hollow a tree → it becomes weak and may fall; also creates cavities that some birds may use. Proper care of trees is essential.
5) 🌳 Arboreal Animals & Seed Dispersal
📘 New word: Arboreal
Arboreal (from Latin arbor = tree) means living in trees. Examples: monkeys, squirrels, many birds.
- Advantages: safety from enemies, plenty of fruits and leaves for food, good view from height.
- Birds use trees to build nests and raise young ones.
🌱 How they help trees
While moving and eating fruits, arboreal animals drop seeds in their droppings. This spreads seeds to new places → new trees grow. A great example of nature’s teamwork! 💫
6) ☀️🌧️❄️ Seasonal Changes in Living Things
We experience three main seasons — summer, the rainy (monsoon) and winter. Seasons affect our clothing and activities, and they affect plants and animals too.
❄️ Winter (season of paangal — leaf fall)
- Many trees shed leaves; animals like sheep, rabbits and some goats grow thicker coats for warmth.
- End of winter → mango blossoms start; in Marathi called mohur.
☀️ Summer
- Tender new leaves appear (often copper-red at first, turning green later); call of the koel is heard.
- Markets are full of mangoes and watermelons; Konkan is famous for mangoes; coastal hills show cashew fruits.
🌧️ Rainy season (Monsoon)
- Black clouds gather in June; the air cools; it turns green everywhere.
- Seeds sprout rapidly; frogs emerge and croak loudly.
🐸 Back to winter
- As rains end and cold returns, frogs go deep underground for a long slumber (7–8 months).
- Farmers plan agricultural tasks according to seasons — sowing, weeding and harvesting.
7) 🧠 What We Have Learnt — Quick Recap
- Living things meet their needs from the environment, but each species’ needs differ.
- Arboreal animals (monkeys, squirrels) live in trees, feed on them and help disperse seeds; many birds build nests on trees.
- Every species thrives only where all its needs are fulfilled — e.g., tigers need prey, water and shelter; aquatic plants live in water.
- Seasonal changes affect living things: winter leaf-fall and thick fur; new leaves and blossoms in early summer; greenery and frogs in the monsoon.
📝 Always remember: The environment changes with the seasons; living things adapt to those changes.
8) 📚 Textbook Exercises — Answers
A) What’s the solution?
Situation: Gurpreet has to go for a hobby class on a hot summer afternoon.
Solution (safety tips) ✅
- Wear light-coloured cotton clothes and a cap/hat; use an umbrella or walk in shade.
- Drink plenty of water/ORS before leaving and carry a bottle.
- Prefer airy footwear; avoid strenuous play in direct sun.
- (Optional) Apply gentle sunscreen on exposed skin if available.
B) Think and tell.
- Why do crops rot when water collects after heavy rains?
Because of water-logging: roots don’t get air/oxygen; fungal diseases increase → roots rot and plants die. - Why is the crop poor if rains are weak?
Insufficient water → poor germination, stunted growth, flower/fruit drop; soil nutrients are not carried to roots properly. - Why does the Indian rat snake (dhaman) live around fields?
Fields have abundant food (rats, frogs, small animals) and hiding places; water is often nearby. - Coats of furry animals in snowy regions — thick or sparse?
Thick, to trap air and conserve heat in the cold.
C) Find out.
- Famous fruits of regions in Maharashtra:
- Nagpur — Oranges 🍊
- Gholvad (Dahanu) — Chikoos/Sapota 🍐
- Saswad (Purandar region) — Figs/Anjeer 🫙
- Deogad/Devgad — Alphonso (Hapus) Mangoes 🥭
- Jalgaon — Bananas 🍌
- Why these fruits grow there: suitable climate, rainfall, temperature and soil conditions; coastal breezes (for Alphonso), black soil and irrigation (for oranges/bananas), dry warm slopes (for figs), sandy lateritic coastal soils (for chikoos).
D) Answer the following questions.
- How are plants useful to us?
They provide food (grains, vegetables, fruits), materials (cotton, wood, medicines, flowers), and oxygen. We cultivate them, water them, add manure and protect them with pesticides when needed. - What is meant by ‘arboreal’ animals?
Arboreal animals are those that live in trees, e.g., monkeys, squirrels, many birds. Trees offer food and safety; they, in turn, help trees by dispersing seeds. - What changes do we see in trees at the beginning of March?
End of winter brings mango blossoms (mohur); many trees put out new tender leaves (copper-red at first, then green) — the onset of summer.
E) Fill in the blanks.
- After the rainy season (monsoon), winter comes again.
- We keep animals because animals meet some of our needs.
- We spray pesticides to prevent insects from attacking plants.
- Winter is also known as the season of paangal (falling of leaves).
💡 Quick Answers to “Can you tell?” in the lesson
- Which tree in the picture (riddle)? — Banyan 🌳
- From where do we get silk? — From silkworms (reared on mulberry leaves).
- How are trees useful for monkeys and squirrels? — They provide home, safety and food; branches help movement; fruits and leaves feed them.
- How are trees useful for birds? — Nesting sites, food (fruits, insects, nectar), and shelter.
- What happens if termites hollow a tree? — The tree becomes weak, may dry up or fall; cavities may be used by some birds but the tree needs protection.