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Ileum, caecum and colon of rabbit, showing Appendix vermiformis on fully functional caecum The human vermiform appendix on the vestigial caecum. The appendix was once believed to be a vestige of a redundant organ that in ancestral species had digestive functions, much as it still does in extant species in which intestinal flora hydrolyze cellulose and similar indigestible plant materials. [10]
In humans, the vermiform appendix is sometimes called a vestigial structure as it has lost much of its ancestral digestive function.. Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. [1]
Vestigial structures are anatomical structures of organisms in a species which are considered to have lost much or all of their original function through evolution. [8] These body parts can be classed as additional to the required functioning of the body. In human anatomy, the vermiform appendix is sometimes classed as a vestigial remnant.
The young Robert Ernst Eduard Wiedersheim, probably in early 1874 by Alfredo Noack in Genoa. [1]Robert Ernst Eduard Wiedersheim (21 April 1848 – 12 July 1923) was a German anatomist who is famous for publishing a list of 86 "vestigial organs" in his book The Structure of Man: An Index to His Past History.
Those organs are typically functional in the ancestral species but are now either semi-functional, nonfunctional, or re-purposed. Scientific literature concerning vestigial structures abounds. One study compiled 64 examples of vestigial structures found in the literature across a wide range of disciplines within the 21st century. [73]
In females, the mesonephros degenerates entirely, though vestigial structures such as Gartner's ducts, the epoophoron, and paroophoron are common. In males, a few of the more caudal tubules will survive and give rise to the efferent ductules of the testis , [ 1 ] the epididymis , vas deferens , seminal vesicle , as well as vestigial structures ...
The vomeronasal organ plays an important role with its sensitivity toward chemicals that are related to mating or sensing prey. For example, snakes use the organ to detect the presence of prey or predator by gathering chemical cues in the environment through the flicking behavior of the forked tongue.
As an elusive and unique part of the brain, the pineal gland has the longest history among the body organs as a structure of unknown function – it took almost two millennia to discover its biological roles. [1] Until the 20th century, it was recognised with a mixture of mysticism and scientific conjectures as to its possible nature. [2] [3]