The ratites are a group of flightless birds comprising the ostrich, emu, cassowaries, rheas, and kiwis. All share certain morphological similarities (such as a breastbone without a keel) not found in other birds, but they live on different continents. In the past, some ornithologists regarded their similarities as homoplasies, but they are now thought to be synapomorphies. Based on this information, you would conclude that the ratites were once regarded as a _______ group but are now believed to be _______.
A) polyphyletic; paraphyletic
B) paraphyletic; monophyletic
C) polyphyletic; monophyletic
D) monophyletic; polyphyletic
E) monophyletic; paraphyletic

Question

Quizplus · Accepted Answer

Initially, ratites were considered polyphyletic due to their similarities being seen as homoplasies (convergent evolution), but now they are considered monophyletic as their similarities are seen as synapomorphies (shared derived traits from a common ancestor).

The Ratites Are a Group of Flightless Birds Comprising the Ostrich