How is it that Humans & Chimps are both Apes, but not their common ancestor?

"Ape" is not a scientific word. It sometimes means both Hominidae and Hylobatidae families, and some people also call "apes" the japanese tailless macaque. MRCA of humans and chimpanzee is a Hominidae, so is MRCA of this one and gorillas, same thing for orangutans. Our MRCA with gibbon is an Hominoidae. If you could see one of them, you would call it an "ape" @ JV You're right, but 'Primate" is a wide order that also contains monkeys, lemurs tarsiers etc. Ida (Darwinius masillae - 45 million years) is close to MRCA of these groups. Ida looks like a lemur nobody would have called her an ape. It was long before the ancestor OP is interrested in.

It is a tacit to end the argument quick because no one knows what a common ancestor is and afraid to ask. Lawyer's tacit, win argument by using similar terms that is unknown to the other party of the argument. They are all apes except humans and Neanderthal. It has to do with brain size because humans have a human brain on top of the animal brain. Even Homo Erectus was an ape according to brain size just they lived in caves, walked upright and may have made/used fire/tools.

Humans are indeed classified as "Great Apes." along with gibbons, Chimpanzee, bonobo, orangutan, gorillas. "ape (mammal) any tailless primate of the families Hylobatidae ( gibbon s) and Hominidae ( chimpanzee s, bonobo s, orangutan s, gorilla s, and human beings). Apes are found in the tropical forests of western and central Africa and Southeast Asia . Apes are distinguished from monkeys by the complete absence of a tail." Apes have a larger brain than other primates & tend to be better at learning & problem solving than other animals. Humans are an ape & did evolve from more primative apes as did all the other Great Apes. Ardipithecus ramidus (Ardi) is the closest securely researched thing to a common ancestor of humans, bonobos & chimps discovered to date. While Ardi's feet were somewhat like a chimps with a big toe configured like a thumb and the brain was about the same size as a chimp, it walked upright & had very small canine teeth when compared to other apes. http://www.britannica.com/facts/5/171060/great-ape-as-discussed-in-ape-mammal http://news.nationalgeographic.com/news/2009/10/091001-oldest-human-skeleton-ardi-missing-link-chimps-ardipithecus-ramidus.html

The common ancestor of chimps and hominids is not referred to as being an ape because the more correct term PRIMATE is or should be used!

Well, you are answering your own question. It is a pity though that your justification is a word game and is incorrect. The common anti-evolutionist question is "If humans evolved from chimpanzees, why are their still chimpanzees?", and its equivalent variations. You are missing two very important concepts that derive from evolutionary theory: Common Descent and Nested Hierarchies. Evolution expects that all life on earth is the result of evolution from a single ancestral life form, as there is no evidence currently to suggest the contrary (Science always talks in terms of what is known <now>. There is no "eternal truths" in science). This is another way of saying that all life on earth is genealogically related to each other. Given that, we can look at groups of animals and find nested hierarchies. For (a simplified) example: 1. 400 mya, there was a group of fish called lobed-finned fish. Some populations remained with the adaptations for an aquatic life, while other evolved structures (in this case, we will include behaviors under the term "structure") that gave those populations the ability to live out of the water. The later populations are the ancestors of today's Tetrapods and are a subset of the lobed-fins. 2. Some Tetrapods evolved water proofed skin, and eggs that allowed those Tetrapods to reproduce outside the water. These populations are the ancestors of today's Amniotes and are a subset of the Tetrapods. 3. Some Amniote populations evolved structures to a endothermic control, improved hearing, and feeding young birth from maternal secretions (i.e. milk). These populations are the ancestors of today's Mammals and are a subset of the Amniotes. 4. Some Mammal populations evolved stereoscopic vision and greater forelimb (hand) dexterity, allowing them to live in trees. These populations are the ancestors of today's Primates and are a subset of the Mammals. 5. Some Primate populations evolved structures that allowed them to move through trees by swinging from branch to branch. These populations are the ancestors of today's apes and are a subset of the Primates. 6. Some ape populations evolved structures that allowed them to move through the tree like the other apes, but with increased size. The populations are the the ancestors of today's great apes and are a subset of apes. 7. Some great ape populations evolved structure that allowed them to locomote on the ground by a technique called "fist-walking". The other did not. The former populations are the ancestors of today's Orangutans, the rest the other great apes. All of these are subsets of the great apes. 8. Some non-orang populations evolved structures that had the effect of allowing them to exploit fruits as a food source. These populations include the ancestors of today's chimps, bonobos and hominids, and are a subset of the non-orang great apes. 9. Some populations of the chimp/bonobo/hominid ancestors evolve structures that allowed them to use striding bipedal locomotion/ Those populations are the ancestors of today's humans. All of the above are extensively documented from several lines of investigation from biology. So the short answer is that all the descendants of the populations split off in step 5 are apes, by definition, including all population that subsequently went extinct. wl