Banded archerfish colourations, such as yellow, have been observed. Four to six broad black bars may be present on the dorsal side. The first bar is found anterior to the operculum, the bony plate covering the gills, and the second is found behind the operculum. The third bar is found below the origin of the dorsal fin, the fourth bar below the soft dorsal, and the fifth (if any) on the area between the anal fin and caudal fin (caudal peduncle). These bars become shorter as the fish ages. The lateral line curves upwards at the area between the fourth and ninth
History of model organisms respective work on natural selection and the genetics of heredity. These early works in finding standards to compare organisms against continued into the 20th century as the first model organisms were brought into laboratories. Beginning in the early 1900s "Drosophila" entered the research laboratories and opened up the doors for other model organisms like Tobacco mosaic virus, E. coli, C57BL/6 (lab mice), etc. These organisms have led to many advances in the past century. Some of the first work with what would be considered model organisms started because Gregor Johann Mendel felt that the views of Darwin were insufficient in