Hennig, the creator of the systematics, proposed that homologies should be distinguished between primitive or ancestral (plesiomorphies) and derive...

Hennig, the creator of the systematics, proposed that homologies should be distinguished between primitive or ancestral (plesiomorphies) and derived (apomorphies), only the latter being informative for grouping organisms. Derived characteristics shared by species of the same group are called:


Simplesiomorphies
Paraphyletics
Synapomorphies
Merophyletics
Exclusives