Green lizards were observed in the region in the image. changes in the geography of the region caused the formation of a stream, which divided the region into two halves. the left half developed a dark green environment, and the right half a comparatively lighter green environment. as a result, two geographically isolated populations, dark and light green lizards inhabited either side of the stream. the region on the right has more light green lizards as a result of . the new species will develop by way of . 1. a. natural seletion b. postzygotic isolation c. harmful mutation 2. a. sympatric speciation b. allopatric speciation c. convergent evolution