The ratites are a group of flightless birds comprising ostrich, emu, cassowary, rhea, and kiwi.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, the similarities among ratites were thought to be the result of convergent evolution, suggesting a polyphyletic origin (arising from multiple ancestral lines). However, current understanding based on shared derived characteristics (synapomorphies) supports the idea that they are monophyletic, meaning they descended from a common ancestor.

The Ratites Are a Group of Flightless Birds Comprising Ostrich