 Phenotype. The phenotype is the composite of an organism's observable characteristics or traits, such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior such as a bird's nest. The phenotype results from the expression of an organism's genetic code, its genotype, as well as the influence of environmental factors and the interactions between the two. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. The well-documented polymorphism is labrador retriever coloring, while the coat color depends on many genes It is clearly seen in the environment as yellow, black and brown. This genotype phenotype distinction was proposed by Wilhelm Johansson in 1911 to make clear the difference between an organism's heredity and what that heredity produces. The distinction is similar to that proposed by August Weisman, who distinguished between germplasm heredity and somatic cells the body. The genotype phenotype distinction should not be confused with Francis Crick's central dogma of molecular biology, which is a statement about the directionality of molecular sequential information flowing from DNA to protein, and not the reverse. Richard Dawkins in 1978 and then again in his 1982 book The Extended Phenotypes suggested that bird nerfs and other adult structures such as catas fly larvae cases and fever dabs can be considered as extended phenotypes.