3.1M Diversity of Living and non-living Things

Chapter 1: Diversity of Living and Non-living Things | P3 Science
Chapter 1 · Primary 3 Science
Diversity of Living and
Non-living Things
📚 Section A — Revision Notes

🎯 What I Will Learn

  • What is diversity?
  • What is classification?
  • How can we show classification?
  • What are living and non-living things?
  • What do living things need to stay alive?
  • What are some other characteristics of living things?
1
What Is Diversity?
  • There are many things around us. Some are living things. Others are non-living things.
  • Diversity refers to the great variety of living things and non-living things around us.
  • We classify the diversity of things around us to understand them better.
2
What Is Classification?
  • Putting things into groups is called classification.
  • We can classify things based on their features, also known as characteristics. Examples: size, shape and colour.
  • Things with similar characteristics are placed in the same group.
  • The same things can be classified in many different ways.
Similarities — characteristics that two or more things have in common.
E.g. A bird and a bee both have wings. This is a similarity.
Differences — characteristics that two or more things do not have in common.
E.g. A bird has two legs, but a bee has six legs. This is a difference.
  • Classification helps us understand and study the diversity of things around us better.
  • Classification helps us organise things and show their similarities and differences clearly.
3
How Can We Show Classification?
  • We can show classification in different ways: using pictures, tables or graphic organisers.
Animals classified by number of legs Three columns: no legs (snake), two legs (penguin), four legs (cat) No legs Two legs Four legs Snake Penguin Cat
Animals with no legs Animals with two legs Animals with four legs
Snake Ostrich Elephant
Fish Penguin Cat
  • A flow chart is a common graphic organiser.
  • In a flow chart, each ◇ diamond shape has a Yes/No question. The answers help us classify things.
Animals Do they have legs? No Snake Fish Yes Do they have two legs? No Elephant Cat Yes Ostrich · Penguin
💡
Exam Tip — Reading Flow Charts
  • If the question says ‘Based on the flow chart’, use only the information from the flow chart. Do not use outside knowledge.
  • Example: If asked for a similarity between elephant and ostrich based on the flow chart above, the answer is “Both have legs” — not “Both are animals” (not shown in the chart).
  • To check your answer: write the names into the flow chart and trace through each question.
⚙️ Worked Example 1.1 — Flow Chart (P, Q, R)
Flow chart: Living things → Can it move from one place to another?
  • No → P
  • Yes → Can it fly?
    • No → Q
    • Yes → R

Which best represents P, Q and R from: Crow, Grass, Snail?
How to solve:
P cannot move → Grass (plants cannot move from place to place).
Q can move but cannot fly → Snail.
R can move and can fly → Crow.

Answer: P = Grass, Q = Snail, R = Crow → Option (3)
4
What Are Living and Non-living Things?
  • We can classify things around us into living things and non-living things.
  • Living things are things that are alive. (e.g. tree, cat, human)
  • Non-living things are things that are not alive. (e.g. cup, clock, chair)
  • Living things and non-living things are found all around us.
  • Some objects contain both — e.g. a potted plant: the plant (living) sits in a pot (non-living).
Living and non-living things Left shows living things: tree, cat, girl. Right shows non-living things: cup, clock, chair. ✓ Living things ✗ Non-living things Tree Cat Girl Cup Clock Chair
5
What Do Living Things Need to Stay Alive?
  • Living things need air, water and food to stay alive.
  • If living things do not have air, water or food, they will die.
💨 Air
  • Living things need air to stay alive. Air contains oxygen.
  • Animals that live on land breathe in air from their surroundings.
  • Animals that live in water have special body parts to help them get air (e.g. fish use gills).
  • Plants also need air to stay alive.
🎯
Get It Right!
✗ Wrong Animals that live in water, such as fish, do not need air.
✓ Correct Fish are living things, and all living things need air. Fish have special body parts called gills to help them get air from the water they live in.
👍
Good to Know
Divers who go into the deep sea need to carry oxygen tanks with them. The oxygen tank allows them to breathe underwater.
💧 Water
  • Living things need water to stay alive.
  • We need water to digest food, remove waste from our body and carry out daily activities.
  • Plants need water to make food. Without water, plants will die.
👍
Good to Know
We need to drink enough water every day. Not drinking enough water can harm our body. When we exercise, we sweat and lose water — that is why we feel thirsty.
🍎 Food
  • Living things need food to stay alive.
  • Food gives living things energy. Food also helps living things grow.
  • Animals eat food.
  • Plants do not eat food. They make their own food when they get air, water and light.
🎯
Get It Right!
✗ Wrong Plants get food from the soil.
✓ Correct Plants do not get food from the soil. They get water and minerals from the soil. They make their own food when there is light.
👍
Good to Know
Animals only eat food that is suitable for them. Not all animals will eat all types of food. Cows eat plants only; tigers eat meat only. If a cow is given meat, it cannot survive.
📋 Checkpoint 1.1
1. Name three things that living things need to stay alive.
Living things need air, water and food to stay alive.
⚙️ Worked Example 1.2 — Grasshopper in Jars
Four set-ups, each a glass jar with a grasshopper and leaves:
  • Set-up A: Water in bowl + leaves + lid with holes
  • Set-up B: Water + leaves + lid without holes (no air)
  • Set-up C: Leaves only + lid without holes (no air, no water)
  • Set-up D: Water + lid with holes (no food)

Q: In which set-up will the grasshopper still be alive after one week?
Grasshopper jar experiment — four set-ups Set-up A has water, leaves and lid with holes — grasshopper stays alive. Set-ups B, C and D are missing one need each, so the grasshopper dies. Set-up A ✓ Air ✓ Water ✓ Food ALIVE ✓ no holes Set-up B ✗ Air ✓ Water ✓ Food DIES ✗ no holes Set-up C ✗ Air ✗ Water ✓ Food DIES ✗ Set-up D ✓ Air ✓ Water ✗ Food DIES ✗ Which set-up will keep the grasshopper alive after one week? = hole in lid (air gets in) = solid lid (no air)
Answer: Set-up A.
Set-up A has water, food (leaves) and air (holes in lid). The grasshopper is a living thing — it needs all three to stay alive.
6
What Are Some Other Characteristics of Living Things?
  • Living things have many characteristics. Some make them different from non-living things.
📈
They can Grow
Become bigger and more complex
👁️
They can Respond
React to changes around them
🐣
They can Reproduce
Have young; ensure survival of their kind
📈 Living things can grow
  • Living things can grow. They become bigger in size.
  • Living things also become more complex as they grow — they may develop new body parts. (e.g. tadpole grows legs as it becomes a frog)
  • Animals use the food they eat to grow. Plants use the food they make to grow.
Tadpole grows into a frog Three stages showing a tadpole growing into a frog, with legs appearing at each stage. Stage 1 Stage 2 Stage 3 grows! grows! Tadpole Tadpole with legs Frog Living things grow bigger and become more complex over time.
👁️ Living things can respond to changes
  • Living things can respond to changes around them.
  • Examples of animals responding: A millipede curls up when touched. A boy covers his ears when music is loud.
  • Plants also respond: plants bend towards sunlight to make food. The mimosa plant (touch-me-not) closes its leaves when touched.
🎯
Get It Right!
✗ Wrong Plants are non-living things because they do not move.
✓ Correct Plants are living things. They do not move from place to place, but they move to respond to changes around them.
Plants respond to changes Left: a potted plant bending towards sunlight. Right: a mimosa plant closing its leaves when touched. Plant bends towards sunlight Mimosa closes when touched bends towards light Plants bend towards sunlight to make food. touch! leaves close! Mimosa (touch-me-not) closes its leaves when touched.
🐣 Living things can reproduce
  • Living things can reproduce — this means they can have young.
  • Living things reproduce to ensure the survival of their kind.
  • If living things do not reproduce, they would become extinct (no more of their kind).
  • Some animals reproduce by giving birth (e.g. cats, dogs). Some reproduce by laying eggs (e.g. chickens, fish, frogs).
  • Some plants reproduce through seeds. Some reproduce through spores.
Living things can reproduce Some animals give birth Some animals lay eggs A cat gives birth to kittens. A chicken lays eggs. The eggs hatch into chicks.
🎯
Get It Right!
✗ Wrong Seeds are non-living things.
✓ Correct Seeds are living things. Under the right conditions, they grow into plants, which are living things.
🎯
Get It Right!
✗ Wrong Everything that moves is a living thing.
✓ Correct Not everything that moves is a living thing. Living things move by themselves. Non-living things (like toy robots) move with the help of batteries — remove the batteries and they stop.
📊 Living vs Non-living Things
Living Things ✔ Non-living Things ✗
✔Need air, water and food ✗Do not need air, water and food
✔Grow ✗Do not grow
✔Respond to changes ✗Do not respond to changes
✔Reproduce ✗Do not reproduce
💡 Memory Trick — Mnemonic
Ned’s Grandma Repairs Rockets!
N
Need air, water & food
G
Grow
R
Respond to changes
R
Reproduce
💡
Exam Tip — Answer Phrasing
When asked for a characteristic of living things, always state it as a characteristic, not as what the animal did.

Question: A pangolin curls into a ball when attacked. Which characteristic of living things does this show?

✗ Do NOT say: “A pangolin responds to changes.”
✓ Correct: “Living things can respond to changes.”

Follow the phrasing in the question exactly.
📋 Checkpoint 1.2
1. State four characteristics of living things.
1. Living things need air, water and food to stay alive.
2. Living things can grow.
3. Living things can respond to changes.
4. Living things can reproduce.

⚡ Chapter Summary

  • Diversity = great variety of living and non-living things around us.
  • Classification = putting things into groups based on characteristics.
  • Classification can be shown using pictures, tables, and flow charts.
  • Living things are alive; non-living things are not alive.
  • Living things need air, water and food to stay alive.
  • Living things can grow, respond to changes, and reproduce.
  • Mnemonic: Ned’s Grandma Repairs Rockets! (N-G-R-R)

✏️ Test Yourself

1. It had not rained for a month. The grass behind Fiza’s school died. Which characteristic of living things does this show?
  • 1Living things need air to stay alive.
  • 2Living things need soil to stay alive.
  • 3Living things need light to stay alive.
  • 4Living things need water to stay alive.
2. Ali adopted a cat. After a few years the cat grew from 2 kg to 5 kg.

(a) Which characteristic of living things did the cat show?
Living things can grow.
(b) State one other characteristic of living things. (Do not repeat your answer from part (a).)
Accept any one of the following:
• Living things need air, water and food to stay alive.
• Living things can respond to changes.
• Living things can reproduce.
✏️ Test Yourself — Take the Chapter 1 Quiz →

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P3 Science Chapter 1 — psle.edu.sg

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