[jamesqf]

Originally Posted by SuperTrooper

Yup, all birds look alike.

Now is that what I said? No, I said that all GENERALIST birds have pretty much the same shape. Maybe that's not the right ecological term - I mean birds that fill the ecological niche of living around forest edges, and eating seeds, insects, and such. They look alike because their shape is the most efficient for doing their particular "job".

Indeed, we can use your examples as further evidence. Take for instance your emu, a bird whose niche it is to run around open grasslands. Looks an awful lot like an ostrich or a rhea, doesn't it? Just as your pelican shares similar features with a flamingo or stork.

Or consider another example of form-follows-function.

This: Google Image Result for http://ukmoths.org.uk/images/HummingbirdHawkMothSF.jpg

and this: Google Image Result for http://www.dnr.sc.gov/news/Yr2006/june12/hummingbird.jpg

Which is the Prius, and which the Honda copy?