Growing taller with age is something that children notice and an increase in height is often celebrated with a height chart. Young children recognise grown-ups from secondary sexual characteristics in humans, as well as changes in clothing and cultural aspects – these changes also occur as humans age. Children have some ability to recognise some animals and plants as adults and understand that animals change as they develop, as do plants. This chapter considers changes in living organisms, including the influence of the seasons and the weather on plants and animals as well as themselves.