Search results
Results from the WOW.Com Content Network
Many examples of these are vestigial in other primates and related animals, whereas other examples are still highly developed. The human caecum is vestigial, as often is the case in omnivores , being reduced to a single chamber receiving the content of the ileum into the colon .
Comparative study of the anatomy of groups of animals or plants reveals that certain structural features are basically similar. For example, the basic structure of all flowers consists of sepals, petals, stigma, style and ovary; yet the size, colour, number of parts and specific structure are different for each individual species. The neural ...
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]
Other examples of living fossils are single living species that have no close living relatives, but are survivors of large and widespread groups in the fossil record. For example: Ginkgo biloba; Syntexis libocedrii, the cedar wood wasp; Dinoflagellates (typified on coccoid dinocysts: occasionally calcareous cell remnants)
A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales, and the forelegs of four-legged vertebrates like horses and crocodilians are all derived from the same ancestral tetrapod structure.
That this vestigial response occurs even before becoming consciously aware of a startling noise would explain why the function of ear-perking had evolved in animals. The mechanism serves to give a split-second advantage to a startled animal – possibly an animal being stalked and hunted.
Among animals, there exists a single known example of an apparently freely rotating structure, though it is used for digestion rather than propulsion: the crystalline style of certain bivalves and gastropods. [19]: 89 The style consists of a transparent glycoprotein rod which is continuously formed in a cilia-lined sac and extends into the stomach.
The remains of decaying plants or animals, or their tissue parts, and feces gradually lose their form due to physical processes and the action of decomposers, including grazers, bacteria, and fungi. [1] Decomposition, the process by which organic matter is decomposed, occurs in several phases.