the ultimate source of genetic differences among species is: the genotype of an organism constitutes its observable characteristics. an individual's observable characteristics are called

Genetic variation refers to genetic differences that exist among individuals in a population at a particular time Without mutations, evolution would not be possible The genetic makeup of a cell or organism constitutes its genotype Mutations are the ultimate source of differences among organisms’ genotypes Polymorphism is any genetic difference among individuals that is common enough that it would almost certainly be present in a group of 50 or more randomly chosen individuals Phenotype is an individual's’ observable characteristics or traits The different forms of any gene are called alleles, and they correspond to different DNA sequences in the genes. An individual who inherits an allele of the same type from each parent is