(Also spelled ‘paleo-‘). Prefix meaning ‘early’, ‘ancient’ or ‘prehistoric’. Used in terms such as palaeobotany, which is the study of past plant life, and palaeoclimatology, the study of past climates. Scientists study past environments by taking deep cores from ice, soil or lake sediments. The core represents an historic record. As you look deeper down the core you are ‘going back in time’. For example, in a lake sediment core, it is possible to study pollen grains from plants that lived thousands of years ago.