Definition of missing link

The term "missing link" was first coined by British anatomist Thomas Huxley in the mid-19th century to describe a hypothetical creature that would connect the evolutionary gap between humans and lower primates. At the time, scientists believed in a strict linear progression of evolution from simple organisms to complex ones, with humans occupying the highest rung on the evolutionary ladder. The supposed existence of a missing link was seen as crucial to the understanding of evolution, as it would help to bridge the apparent gap in the fossil record between hominids (human ancestors) and apes. Huxley chose the term "missing link" to describe this elusive link because it suggested that this creature was lost or incomplete, and its discovery was seen as a matter of solving a puzzle or closing a gap. However, the concept of the missing link has since been criticized by modern evolutionary biologists, who argue that evolution is more complex and nuanced than a simple linear progression and that the variation within species and the divergence of related species over time present a more accurate depiction of the evolutionary process. Nonetheless, the term "missing link" has become a popular and oft-used term in popular culture, even if it no longer carries the same scientific weight.