Form 2 · Chapter 1

Diversity of Organisms

Living things come in a huge variety of shapes, sizes and habitats. This is called biodiversity.

What is biodiversity?

Biodiversity means the variety of living things (organisms) found on Earth. From tiny bacteria to giant trees, from insects to whales, Malaysia alone is home to thousands of different species. Every organism shares a set of characteristics that make it a living thing.

Key idea

All living things carry out seven life processes: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition. A quick way to remember them is the word MRS GREN.

Life processes

Movement lets an organism change position. Respiration releases energy from food. Sensitivity means responding to the surroundings, such as a plant bending toward light. Growth is an increase in size. Reproduction produces new individuals. Excretion removes waste products, while nutrition is taking in food or making it by photosynthesis.

  • Plants make their own food and usually cannot move from place to place.
  • Animals take in ready-made food and can usually move.
  • Microorganisms are so small they need a microscope to be seen.

Why diversity matters

A wide diversity of organisms keeps nature balanced. Different species depend on one another for food, shelter and oxygen. If many species disappear, the whole environment can become unstable.

Example

A single rainforest tree may support birds, insects, fungi and mosses all at once, showing how one habitat can hold great biodiversity.

Remember

  • Biodiversity = variety of living things.
  • All living things show MRS GREN life processes.
  • Microorganisms need a microscope to be seen.

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