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The smelling organs of the terrestrial coconut crab are similar to those of insects. [ 141 ] In an odd cross-phyla example, an insect, the hummingbird hawk-moth ( Macroglossum stellatarum ), also feeds by hovering in front of flowers and drinking their nectar in the same way as hummingbirds and sunbirds .
The opposite of homologous organs are analogous organs which do similar jobs in two taxa that were not present in their most recent common ancestor but rather evolved separately. For example, the wings of insects and birds evolved independently in widely separated groups , and converged functionally to support powered flight , so they are ...
Functionally similar features that have arisen through convergent evolution are analogous, whereas homologous structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions.
[23] [24] [25] Analogous organs in other animals similar to humans continue to perform similar functions. The coccyx , [ 26 ] or tailbone, though a vestige of the tail of some primate ancestors, is functional as an anchor for certain pelvic muscles including: the levator ani muscle and the largest gluteal muscle, the gluteus maximus.
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]
The development and spread of antibiotic resistant bacteria provides evidence that evolution due to natural selection is an ongoing process in the natural world. Natural selection is ubiquitous in all research pertaining to evolution, taking note of the fact that all of the following examples in each section of the article document the process.
Homoplasy can arise from both similar selection pressures acting on adapting species, and the effects of genetic drift. [2] [3] Homoplasy is the similarity in a feature that is not parsimoniously explained by descent from a common ancestor. Most often, homoplasy is viewed as a similarity in morphological characters.
Bottom: in a separate species , a gene has a similar function (histone-like nucleoid-structuring protein) but has a separate evolutionary origin and so is an analog. Sequence homology is the biological homology between DNA , RNA , or protein sequences , defined in terms of shared ancestry in the evolutionary history of life .