There were three major theories on the basis of inheritance that existed prior to Mendel. Each of these periodically gained and lost popularity over time, but remnants of each existed well into the nineteenth century. These included: Pangenesis: Pangenesis is the belief that each part of the body contributed a miniature version of itself to the offspring. For example, each finger would contribute a small version of itself, as would each ear and toe. The inheritance of nonphysical characteristics, such as behavior, presented special problems for the supporters of this theory. Variations of pangenesis were supported by a number of people, including the Greek philosopher Hippocrates, Hugo De Vries, and Charles Darwin. Preformation: The theory that a tiny preformed human, called a homunculus, resided inside of either the egg or sperm cell. This was later adapted to the idea that all parts of the adult are formed early in the development of the zygote, and simply increase in size over time. This theory was supported by seventeenth century scientists such as Anton von Leeuwenhoek, Marcello Malpighi, and Jan Swammerdam. Blending: Under this theory, offspring represented a mixture of the hereditary material. The hereditary material was not a distinct particle, but rather a malleable substance that could be changed over the course of a few generations. This theory was supported by Joseph Kolreuter (1733–1806) and many of the other early researchers of plant hybrids. While Gregor Mendel is considered to be the father of genetics due to his application of the empirical approach to the study of inheritance, he actually represented just one of a long lineage of individuals who were studying inheritance.
