Living Things, Habitats & Adaptations
MRS GREN, Singapore habitats, animal adaptations, classification — with interactive questions and PSLE model answers.
MRS GREN — The 7 Life Processes
To be classified as living, an organism must carry out ALL 7 life processes. Missing even one means it is not living (e.g. a robot can move and respond, but cannot grow, reproduce or excrete — so it is NOT living).
Singapore Habitats & Adaptations
| Singapore Habitat | Challenge | Example Adaptation |
|---|---|---|
| Mangrove (Sungei Buloh, Pasir Ris) | Waterlogged, salty soil; flooding | Pneumatophores (aerial roots) for breathing; waxy leaves to reduce salt |
| Rainforest (Bukit Timah) | Competition for light; heavy rain | Large leaves to capture more light; drip tips to shed water quickly |
| Coral reef (Sisters' Islands) | Saltwater, water pressure, currents | Streamlined bodies; gills to extract dissolved oxygen |
| Urban/garden (housing estates) | Limited food, human disturbance | Monitor lizards are omnivores — eat wide variety of food sources |
Fill in the Blanks
Word Bank: MRS GREN · habitat · adaptation · vertebrates · invertebrates · warm-blooded · cold-blooded · camouflage · excretion · classification
1. The acronym helps us remember the seven life processes all living things must carry out.
2. The natural environment where an organism lives and finds food, water, shelter and a place to reproduce is called its .
3. A feature (physical, behavioural, or physiological) that helps an organism survive in its specific habitat is called an .
4. Animals with a backbone (spine) are called . Examples include fish, frogs, lizards, birds, and mammals.
5. Insects, worms, crabs, and jellyfish are examples of — animals without a backbone.
6. Mammals and birds are — their bodies maintain a constant internal temperature regardless of the surroundings.
7. Fish, reptiles, and amphibians are — their body temperature changes with their surroundings.
8. A stick insect's body looks exactly like a twig — this is an example of , which helps it avoid predators in Bukit Timah forest.
9. Removing waste products produced by an organism's chemical reactions is one of the 7 life processes. It is called .
10. Sorting living things into groups based on shared features is called .
True or False
Multiple Choice Questions
1. A student finds an object in the forest that moves when touched, responds to light, but does NOT grow, reproduce, or excrete. What can she conclude?
2. The mangrove tree has special roots called pneumatophores that stick up out of the waterlogged mud. What is the BEST explanation for this adaptation?
3. A monitor lizard is found at MacRitchie Reservoir in Singapore. It eats fish, eggs, insects, and even fruit. How would you classify it?
4. Which group of animals is correctly paired with ONE shared feature?
5. Bats are mammals that are active at night. They use echolocation to hunt insects in the dark. This is an example of which type of adaptation?
Singapore Animals — Adaptations & Reasons
| Animal (Singapore) | Adaptation | How it helps survival |
|---|---|---|
| Dugong (Chek Jawa) | Streamlined body; paddle-like flippers | Reduces water resistance for efficient swimming; flippers for steering |
| Proboscis monkey (Sungei Buloh) | Enlarged nose; can swim between mangrove islands | Large nose amplifies warning calls to warn group of danger; swimming for foraging |
| Dragonfly larva (freshwater ponds) | Gills for breathing underwater | Extracts dissolved oxygen from water to survive in aquatic habitat |
| Horseshoe crab (Changi beach) | Hard dome-shaped shell | Protects soft body from predators and physical damage in the rocky/sandy intertidal zone |
| Otters (Marina Reservoir) | Webbed feet; streamlined body; waterproof fur | Webbed feet for swimming; fur traps air for insulation and buoyancy in water |
Open-Ended Questions (PSLE Style)
Q1. [2 marks] A scientist finds an object that moves and responds to light but does not grow, reproduce, or excrete waste. Is it a living thing? Explain your answer fully.
Q2. [2 marks] Explain TWO adaptations of the mangrove tree found in Sungei Buloh Wetland Reserve and how each helps it survive in its habitat.
2. Prop roots / buttress roots: These spread outward from the base of the trunk. They anchor the tree firmly in the soft, unstable muddy ground, preventing it from toppling over during tides and strong winds.
Q3. [3 marks] Compare a rainforest habitat and a coral reef habitat in Singapore. For each, describe ONE challenge organisms face, and give ONE adaptation of a plant or animal that addresses that challenge.
Coral reef (e.g. Sisters' Islands): Challenge — strong water currents and the need to extract oxygen from water. Adaptation — fish have streamlined body shapes to move efficiently against currents, and gills to extract dissolved oxygen from seawater for respiration.
Q4. [Extended] [3 marks] A student argues: "Fire is a living thing because it moves, grows, and uses fuel (nutrition)." Do you agree? Explain why or why not, naming the specific life processes fire is missing.
Most critically: fire cannot reproduce. A living thing must be able to produce offspring. Since fire fails to carry out all 7 MRS GREN life processes, it is NOT a living thing.
Key Facts to Remember
- MRS GREN: ALL 7 must be present — Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition
- Fire = NOT living (cannot reproduce). Seed = LIVING (dormant). Wooden chair = ONCE-LIVING
- Vertebrates (backbone): mammals, birds, reptiles, amphibians, fish. Invertebrates: insects, crabs, jellyfish, worms
- Warm-blooded: mammals & birds. Cold-blooded: fish, reptiles, amphibians
- Adaptations: structural (body features), behavioural (actions), physiological (internal processes)
- Singapore habitats: mangrove, rainforest, freshwater, coral reef — know one adaptation for each
- ALWAYS state the adaptation AND explain HOW it helps survival — both parts needed for full marks