All living things share some common vital functions for sustaining life. There is a wide variety of living things on Earth. Scientists study living things by putting them into different groups according to some key features. These key features are related to the adaptation of living things to their living environments. The diversity of living things is important for sustaining the natural environment and we have to try our best to conserve the biodiversity.

Through the study of living things in this Unit, students will develop some science process skills such as observing and classifying. Learning about the grouping of living things helps students appreciate the unifying concepts “systems and organisation”, while relating the key features of different groups of living things to their functions helps students recognise the unifying concepts “form and function”. Through the study of the importance of biodiversity and the effects of human activities, students’ attention is also drawn to the need of conservation of both living things and their environments. This helps illustrate the unifying concepts “change and constancy”.