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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]
The human pineal gland grows in size until about 1–2 years of age, remaining stable thereafter, [20] [21] although its weight increases gradually from puberty onwards. [ 22 ] [ 23 ] The abundant melatonin levels in children are believed to inhibit sexual development, and pineal tumors have been linked with precocious puberty .
The theory of animal-to-human transplants, known as ... Some also argue that there is a lot that can be done to increase the supply of certain organs, like kidneys, from human sources that wouldn ...
Thus the zoologist Newman stated in the Scopes Trial: "There are, according to Wiedersheim, no less than 180 vestigial structures in the human body, sufficient to make of a man a veritable walking museum of antiquities." Some of the vestigial organs or organs containing evolutionary vestigial structures, as listed on the article about him: Adenoids
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.
Conversely, human embryos possess a vomeronasal organ that persists, although this feature is vestigial throughout their lifetime. Primates are phylogenetically divided into Strepsirrhini, species that possess a curly "wet nose" rhinarium, and Haplorhini , those that possess a dry "simple nose" structure.
The term "homology" was first used in biology by the anatomist Richard Owen in 1843 when studying the similarities of vertebrate fins and limbs, defining it as the "same organ in different animals under every variety of form and function", [6] and contrasting it with the matching term "analogy" which he used to describe different structures ...