Ardipithecusand Early Human Evolution in Light of Twenty-First-Century Developmental Biology

Abstract

One specimen of Ardipithecus ramidus, ARA-VP-6/500, is the earliest and also among the most complete fossil hominids ever recovered. Although it took more than a decade to extract, prepare, and analyze (along with a number of other less-complete specimens), the thoroughness of its recovery and preparation has yielded surprising revelations about its environment as well as new knowledge about the divergence of our earliest human ancestors from the last common ancestor they shared with chimpanzees. Decades of groundbreaking discoveries in developmental biology have also transformed our understanding of the evolutionary process itself, especially the need to view the significance of adult anatomical structures holistically. Today, no such structure can be reasonably understood without direct reference to its likely mode of morphogenesis. The twenty-first-century convergence of these two special sources of information requires a radical revision of how our early hominid forebears set the stage for our own sub...