  Democritus seems to have developed a view of reproduction according to which all parts of the body contribute to the seed from which the new animal grows, and that both parents contribute seed (DK 68A141; 143).  The theory seems to presuppose that the presence of some material from each organ in the seed accounts for the development of that organ in the new organism.  Parental characteristics are inherited when the contribution of one or other parent predominates in supplying the appropriate part.  The offspring is male or female according to which of the two seeds predominates in contributing material from the genitals.  In an atomist cosmos, the existence of particular species is not considered to be eternal.  Like some other early materialist accounts, Democritus held that human beings arose from the earth (DK 68A139), although the reports give little detail. 