Why do offspring look like their parents? Even ancient people were aware that the characteristics of an individual plant or animal could be passed between generations. They also knew that some heritable characteristics (such as the size of fruit) varied between individuals, and that they could select for the most favorable traits while breeding crops and animals. The once prevalent (but now discredited) concept of blending inheritance proposed that some undefined essence, in its entirety, contained all of the heritable information for an individual. Much like the mixing of two colors of paint, it was thought that mating combined the essences from each parent. Once blended together, the individual characteristics of the parents could not be separated again.