Two studies address children's emerging understanding of the origins of spe
cies. Elementary-school children, aged 5-12 years, were interviewed about t
heir understanding of biological origins and of natural history (Ns = 49 in
Study 1; 83, with parents, in Study 2). A systematic developmental pattern
in children's explanations for biological origins was demonstrated. There
were age-related shifts from mixed creationist and spontaneous generationis
t explanations, to an exclusive creationism, and finally to evolutionist or
creationist explanations. A child's age, natural history knowledge, and pa
rents' beliefs were independently related to the expression of these explan
ations. It is argued that this developmental pattern emerges from the inter
action between community beliefs and age-related changes in the inductive p
otential of children's naive theories.