Where's the missing link?
Where's the missing link?
Evolutionary biologists are often asked, in regard to the fossil record, "Where's the missing link?" The term "missing link" comes from the "chain of being". This metaphor originated in the renaissance when life was considered a hierarchical chain with humans at the top.

Evolution resembles a tree, not a chain. Trees have branches, not links. Between any pair of organisms, e.g. humans and chimps, there are undoubtedly many intermediates. Finding a "missing link" then creates two more missing links, one to connect the new link to chimps and the other to connect it to humans. Since evolution is a tree and not a chain, newly found "links" can be side branches as easily (more easily) as part of the main path. Missing links are biological misnomers. If you want a missing link, try the hardware store.

Regardless of tree or chain, historical records are incomplete. We won't know the full history of evolution any more than we know the full history of the Egyptian Old Kingdom.