Paleobotany, pay lee oh BOTuh nee, is the study of ancient plants. Paleobotany is a branch of paleontology, the study of ancient plants, animals, and other organisms. Specialists called paleobotanists investigate the evolution of plant life and the origins and relationships of plant groups. They also examine the link between vegetation and the earth's changing climate. Paleobotany includes the study of such simple organisms as ancient algae, fungi, and bacteria. In addition, it involves searching for the earliest evidence of life in rocks more than 3 billion years old.