polygenesis
Biology term referring to the theory that a species or group originated from multiple independent ancestral lines, as opposed to a single origin.
The polygenesis theory holds that a species evolved independently from multiple ancestors.
Monogenesis: the contrasting theory that a species originated from a single ancestral line.
Compound of 多 (た, 'many'), 原 (げん, 'origin'), 発生 (はっせい, 'generation, development'), and 説 (せつ, 'theory'). The exact historical derivation is uncertain; the term is a modern scientific coinage.