Darwin and wallace independently arrived at the same conclusion that species change over time. which observations supported their conclusions? bird families clustered geographically: cockatoos in the malay archipelago and australia, macaws and hummingbirds in the americas. tortoises from different galapagos islands have distinct shells. the fossilized remains of giant sloths were similar to the smaller, living sloths darwin encountered. mockingbirds from different galapagos islands had subtle, consistent differences. the bony shells of armadillos resembled fossilized shells from the extinct glyptodon. birdwing butterflies were found throughout the malay archipelago, but species differed slightly from island to island.