Is Evolution Observable?

[Anomalocaris]

Humans are primates of the genus homo. Apes; chimpanzee, bonobos, gorillas, orang-utans and gibbons (lesser apes) are also primates.

But humans are not apes.

That would not be a modern taxonomicaly point of view. "Ape" in modern classification is generally regarded as being synonomous with family Hominidae. Hominidae includes the genera Homo (humans), Pongo (Orangutan), Gorilla (Gorilla), and Pan (Chimps).

The basis of this is not the subjective assessment of anatomical similarity. It is based on modern reconstruction of genetic lineage, and the commonly accepted modern definition of family as being a natural lineage grouping containing both the last common ancester, and all descendants of that common ancester. If the last common ancester possesses all the traits that would have been needed to classify it as an ape, then all of its descendants would also be apes. If the common ancester of humans and other great apes were alive today, it would have been called an ape because it would have all the attributes thought to distinguish the other member of the ape family. That fact alone, by modern cladistic classification criteria, is enough to, and would necessarily, make humans, a descendant of that ape ancester, also an ape.