An original new science series which explores the key characteristics that divide the main animal and plant groups, and looks at how these characteristics have evolved over time. The information is supported by examples that highlight the quirky and amazing qualities of the natural world, as well as revealing the dazzling variety within each group.Why do Insects Have Six Legs? looks at the features that make insects so unique. It describes how they have evolved over time, and looks at how their movement developed. Insect senses, behaviour and habitats all also feature.