History of botany scope of the subject as technology has opened up new techniques and areas of study. Modern molecular systematics, for example, entails the principles and techniques of taxonomy, molecular biology, computer science and more. Within botany there are a number of sub-disciplines that focus on particular plant groups, each with their own range of related studies (anatomy, morphology etc.). Included here are: phycology (algae), pteridology (ferns), bryology (mosses and liverworts) and palaeobotany (fossil plants) and their histories are treated elsewhere (see side bar). To this list can be added mycology, the study of fungi, which were once treated as plants, but
Human uses of plants in genetic engineering led to developments in crops. Genetically modified crops introduce new traits to plants which they do not have naturally. These can bring benefits such as a decrease in the use of harmful pesticides, by building in qualities such as insect resistance and herbicide tolerance. The ability of trees to graft is occasionally exploited by tree shaping to create living root bridges in Meghalaya and Nagaland states in India and on the islands of Sumatra and Java in Indonesia. The aerial roots of rubber fig trees, "Ficus elastica", are used to form suspension bridges across mountain streams. Plants