What Is a Human? Long-Standing Debate Surrounds Our Family Tree

Homo naledi, shown here in a recreation by paleoartist John Gurch

 Several ancient human species and relatives have been unearthed in bits and pieces over the years, including one with an orange-size brain, another dubbed the "hobbit" for its miniature size and a flat-faced hominin with a huge brow ridge.

Although these finds have opened more windows into the evolutionary landscape in which today's humans arose, some researchers are not convinced such discoveries belong alongside Homo sapiens.

The controversy — whether the human family tree had few or many branches — is part of a long-standing debate between the so-called lumpers and splitters. [...] livescience.com