Singapore N(T)-Level Science, Plants and Ecosystems: living things and their habitats, photosynthesis and plant needs, food chains and food webs, the water cycle and nutrient recycling, and human impact on the environment

What this module is about

The Plants and Ecosystems module of N(T)-Level Science (SEAB 5148) is about living things and the natural world they share: how plants make food, how energy passes from one living thing to the next, how water and nutrients are recycled, and how human choices affect it all. As a Normal (Technical) module it stays close to everyday examples, from a potted plant on a balcony to the litter in a canal.

This overview ties the threads together and links to every dot point page in the module, each with its own worked answers and practice questions.

Living things and their habitats

The module starts with living things and their habitats. Living things share characteristics such as growing, moving, feeding, breathing (respiring), getting rid of waste, sensing their surroundings and reproducing. A habitat is the place where a living thing lives, providing food, water, shelter and space. Plants and animals are adapted to their habitats, for example a cactus stores water for the desert and a fish has gills for living underwater.

Photosynthesis and plant needs

Next comes photosynthesis and plant needs. Green plants make their own food by photosynthesis, using light, water and carbon dioxide, with chlorophyll trapping the light energy in the leaves. They produce glucose (their food) and oxygen. To grow well, plants also need warmth, minerals from the soil and space, which is why a plant left in the dark cannot make food and will not thrive.

Food chains and food webs

The third dot point is food chains and food webs. A food chain shows how energy in food passes from one living thing to another, with arrows pointing from the eaten to the eater. It starts with a producer (a green plant), then consumers, including predators that hunt prey. A food web links several chains together, and a change to one part (such as removing a predator) affects the rest.

The water cycle and nutrient recycling

The fourth dot point is the water cycle and nutrient recycling. In the water cycle the Sun evaporates water from seas and rivers, the vapour cools and condenses into clouds, and water falls back as rain (precipitation) before flowing back to the sea. Decomposers (such as bacteria and fungi) break down dead plants and animals, returning nutrients to the soil so that plants can use them again. These natural cycles keep water and nutrients in constant supply.

Human impact on the environment

The module finishes with human impact on the environment. Human activities cause air pollution (burning fuels), water and land pollution (waste and chemicals) and habitat loss (clearing forests). These harm living things and the planet. People can reduce their impact by reducing, reusing and recycling, saving energy and water, and disposing of waste properly.

How this module is examined

• Give a survival reason for adaptations. Link the feature to the habitat.
• State the inputs and outputs of photosynthesis. Light, water and carbon dioxide in; glucose and oxygen out.
• Read food chain arrows correctly. Arrows point from the eaten to the eater; predict the effect of a change.
• Describe the cycles and link impact to action. Name a pollution type and a matching way to reduce it.

Check your knowledge

A mix of recall and application questions covering the module. Attempt them under timed conditions, then check against the solutions, and use the dot point pages for fuller practice.

1. State two characteristics shared by all living things. (2 marks)
2. Name the three things a plant needs for photosynthesis. (2 marks)
3. State the two products of photosynthesis. (1 mark)
4. In a food chain, what does an arrow point towards? (1 mark)
5. Name the living things that return nutrients to the soil by breaking down dead matter. (1 mark)
6. Give one way a family can reduce their impact on the environment. (1 mark)