The document discusses the classification of living things, including vertebrates which have backbones like mammals, birds, reptiles, amphibians and fish, and invertebrates which do not have backbones such as molluscs, arthropods and worms. It also describes insects and spiders as arthropods, which have three body parts - a head, thorax and abdomen - and notes that different types of living things have different diets, such as herbivores eating plants, carnivores eating meat, and omnivores eating both plants and other animals.