Gregor Mendel's three principles of inheritance apply to phenotypical traits displayed in both plants and animals. Some of these traits include eye color, hair color, ability to roll one's tongue and flower color. Mendel discovered his principles through the experiments he performed using pea plants.
Gregor Mendel, a Central European monk, determined through his studies with pea plants that all organisms obtain their genes in pairs inherited distinctly from each parent. According to Mendel, the observable trait, known as the phenotype, is determined by a pair of genes that make up the genotype. The genes inherited can either be dominant, partially dominant or recessive. A dominant trait appears in the phenotype, a partially dominant trait is partially displayed and a recessive trait does not manifest but can still be passed on to the next generation of offspring.