The Function of Human Appendix - Page 4

Horse Digestive Tract

The human appendix had been proposed to be a vestigial structure, a structure that has lost all or most of its original function, or a structure that has evolved to take on a new function. The vermiform appendix has been proposed to be the shrunken remainder of the cecum that was found in a remote ancestor of humans. A 2013 study, however, refutes the idea of an inverse relationship between cecum size and appendix size and presence. Ceca, which occur in the digestive tracts of many herbivores (e.g. ox, horse), house mutualistic bacteria and ingested small stones that help animals, digest the cellulose molecules found in plants.