Adaptive radiation is the process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography, for example: Darwin's finches. Analogous organs which are not anatomically similar structures though they perform similar functions, are a result of convergent evolution, for example: Wings of butterfly and of birds. Homologous organs which are anatomically similar structures but perform different functions according to their needs, are a result of divergent evolution, for example: Bones of forelimbs in man and whale. Evolution by anthropogenic action means evolution due to human interference, for example: Antibiotic resistant microbes, herbicides resistant varieties and pesticide resistant varieties.