Editing Convergent evolution (section)

== In animal morphology ==

[[File:Ichthyosaur vs dolphin.svg|thumb|upright=1.5|[[Dolphins]] and [[ichthyosaur]]s converged on many adaptations for fast swimming.]]

===Bodyplans ===

Swimming animals including [[fish]] such as [[herring]]s, [[marine mammals]] such as [[dolphins]], and [[ichthyosaur]]s ([[Mesozoic era|of the Mesozoic]]) all converged on the same streamlined shape.<ref>{{cite web |title=How do analogies evolve? |url=http://evolution.berkeley.edu/evolibrary/article/similarity_ms_08 |publisher=University of California Berkeley |access-date=2017-01-26 |archive-url=https://web.archive.org/web/20170402153740/http://evolution.berkeley.edu/evolibrary/article/similarity_ms_08 |archive-date=2017-04-02 |url-status=live }}</ref><ref>{{cite book |last1=Selden |first1=Paul |last2=Nudds |first2=John |edition=2nd |title=Evolution of Fossil Ecosystems |url=https://books.google.com/books?id=LgdL9ZP2ftgC&pg=PA133 |year=2012 |publisher=CRC Press |isbn=978-1-84076-623-3 |page=133 |access-date=2017-01-26 |archive-url=https://web.archive.org/web/20170215082234/https://books.google.com/books?id=LgdL9ZP2ftgC&pg=PA133 |archive-date=2017-02-15 |url-status=live}}</ref> A similar shape and swimming adaptations are even present in molluscs, such as ''[[Phylliroe]]''.<ref>{{Cite web|url=http://www.deepseanews.com/2015/11/meet-the-sea-slug-that-looks-like-a-fish-lives-in-the-deep-sea-and-glows/ |title=Meet Phylliroe: the sea slug that looks and swims like a fish |last=Helm |first=R. R. |date=2015-11-18 |website=Deep Sea News |access-date=2019-07-26 |archive-url=https://web.archive.org/web/20190726003554/http://www.deepseanews.com/2015/11/meet-the-sea-slug-that-looks-like-a-fish-lives-in-the-deep-sea-and-glows/|archive-date=2019-07-26|url-status=live}}</ref> The fusiform bodyshape (a tube tapered at both ends) adopted by many aquatic animals is an adaptation to enable them to [[animal locomotion|travel at high speed]] in a high [[drag (physics)|drag]] environment.<ref>{{cite web |url=http://cetus.ucsd.edu/sio133/PDF/Marine%20Environment%20&%20Secondary%20Marine%20Forms2016.pdf |title=The Marine Environment as a Selective Force for Secondary Marine Forms |last=Ballance |first=Lisa |year=2016 |publisher=UCSD |access-date=2019-09-19 |archive-url=https://web.archive.org/web/20170202025138/http://cetus.ucsd.edu/sio133/PDF/Marine%20Environment%20%26%20Secondary%20Marine%20Forms2016.pdf |archive-date=2017-02-02 |url-status=live }}</ref> Similar body shapes are found in the [[earless seal]]s and the [[eared seals]]: they still have four legs, but these are strongly modified for swimming.<ref>{{cite journal |author1=Lento, G. M. |author2=Hickson, R. E. |author3=Chambers, G. K. |author4=Penny, D. |date=1995 |title=Use of spectral analysis to test hypotheses on the origin of pinnipeds |journal=Molecular Biology and Evolution |volume=12 |issue=1 |pages=28–52 |pmid=7877495 |doi=10.1093/oxfordjournals.molbev.a040189 |doi-access=free}}</ref>

The marsupial fauna of Australia and the placental mammals of the Old World have several strikingly similar forms, developed in two clades, isolated from each other.<ref name=SCM2005>{{cite book |last=Conway Morris |first=Simon |author-link=Simon Conway Morris | year=2005 |title=Life's solution: inevitable humans in a lonely universe |isbn=978-0-521-60325-6 |oclc=156902715 | publisher=Cambridge University Press |pages=[https://archive.org/details/lifessolutionine01conw/page/164 164, 167, 170 and 235] |url=https://archive.org/details/lifessolutionine01conw/page/164 }}</ref> The body, and especially the skull shape, of the [[thylacine]] (Tasmanian tiger or Tasmanian wolf) converged with those of [[Canidae]] such as the red fox, ''[[Vulpes vulpes]]''.<ref>{{cite journal |last=Werdelin |first=L. |journal=Australian Journal of Zoology |volume=34 |issue=2 |year=1986 |pages=109–117 |title=Comparison of Skull Shape in Marsupial and Placental Carnivores |doi=10.1071/ZO9860109}}</ref>

<gallery heights="170px" mode="packed" caption="Convergence of [[marsupial]] and [[placental mammal|placental]] mammals">
File:Vulpes vulpes skeleton.JPG|[[Red fox]] skeleton
File:Beutelwolf fg01.jpg|Skulls of  [[thylacine]] (left),  [[Canis lupus|timber wolf]] (right)
File:Beutelwolfskelett brehm (cropped).png|[[Thylacine]] skeleton
</gallery>

=== Echolocation ===

As a sensory adaptation, [[Animal echolocation|echolocation]] has evolved separately in [[cetaceans]] (dolphins and whales) and bats, but from the same genetic mutations.<ref>{{Cite journal |last1=Liu |first1=Yang |last2=Cotton |first2=James A. |last3=Shen |first3=Bin |last4=Han |first4=Xiuqun |last5=Rossiter |first5=Stephen J. |last6=Zhang |first6=Shuyi |date=2010-01-01 |title=Convergent sequence evolution between echolocating bats and dolphins |journal=Current Biology |volume=20 |issue=2 |pages=R53–R54 |doi=10.1016/j.cub.2009.11.058 |pmid=20129036 |s2cid=16117978 |doi-access=free |bibcode=2010CBio...20..R53L }}</ref>

=== Electric fishes ===

The [[Gymnotiformes]] of South America and the [[Mormyridae]] of Africa independently evolved [[Electroreception and electrogenesis|passive electroreception]] (around 119 and 110 million years ago, respectively). Around 20 million years after acquiring that ability, both groups evolved active [[Electric fish|electrogenesis]], producing weak electric fields to help them detect prey.<ref name="Lavoué Miya 2012">{{cite journal |last1=Lavoué |first1=Sébastien |last2=Miya |first2=Masaki |last3=Arnegard |first3=Matthew E. |last4=Sullivan |first4=John P. |last5=Hopkins |first5=Carl D. |last6=Nishida |first6=Mutsumi |title=Comparable Ages for the Independent Origins of Electrogenesis in African and South American Weakly Electric Fishes |journal=PLOS ONE |volume=7 |issue=5 |date=14 May 2012 |doi=10.1371/journal.pone.0036287 |page=e36287|pmid=22606250 |pmc=3351409 |bibcode=2012PLoSO...736287L |doi-access=free }}</ref>

<gallery class=center mode=nolines widths="" caption="Convergence of [[weakly electric fish]]es">
File:Elephantfish spike waveform.svg|Gymnotiform electrolocation waveform
File:Sternarchorhynchus oxyrhynchus.jpg|A [[Gymnotiformes|gymnotiform]] electric fish of South America
File:Gnathonemus_petersii.jpg|A [[Mormyridae|mormyrid]] electric fish of Africa
File:Elephantfish spike waveform.svg|Mormyrid electrolocation waveform
</gallery>

=== Eyes ===

{{Main|Eye evolution}}

[[File:Evolution eye.svg|thumb|The camera eyes of [[vertebrate]]s (left) and [[cephalopod]]s (right) developed independently and are wired differently; for instance, [[optic nerve]] <sup>(3)</sup> fibres <sup>(2)</sup> reach the vertebrate [[retina]] <sup>(1)</sup> from the front, creating a [[Blind spot (vision)|blind spot]] <sup>(4)</sup>.<ref>{{cite book |last=Roberts |first=M.B.V. |date=1986 |url=https://books.google.com/books?id=ASADBUVAiDUC&pg=PA574 |title=Biology: A Functional Approach |url-status=live |archive-url= https://web.archive.org/web/20160912091025/https://books.google.com/books?id=ASADBUVAiDUC&pg=PA574 |archive-date=2016-09-12 |publisher=Nelson Thornes |page=274 |isbn=978-0-17-448019-8}}</ref>]]

One of the best-known examples of convergent evolution is the camera eye of [[Cephalopod eye|cephalopods]] (such as squid and octopus), [[vertebrate]]s (including mammals) and [[cnidaria]]ns (such as jellyfish).<ref name="Kozmik2008">{{cite journal |last1=Kozmik|first1=Z. |author2=Ruzickova, J |author3=Jonasova, K |author4=Matsumoto, Y. |author5=Vopalensky, P. |author6=Kozmikova, I. |author7=Strnad, H. |author8=Kawamura, S. |author9=Piatigorsky, J. |author10=Paces, V. |author11=Vlcek, C. |display-authors=3 |title=From the Cover: Assembly of the cnidarian camera-type eye from vertebrate-like components |journal=Proceedings of the National Academy of Sciences |date=1 July 2008 |volume=105 |issue=26 |pages=8989–8993 |doi=10.1073/pnas.0800388105 |pmid=18577593 |pmc=2449352 |bibcode=2008PNAS..105.8989K |doi-access=free }}</ref>  Their last common ancestor had at most a simple photoreceptive spot, but a range of processes led to the [[evolution of the eye|progressive refinement of camera eyes]]—with one sharp difference: the cephalopod eye is "wired" in the opposite direction, with blood and nerve vessels entering from the back of the retina, rather than the front as in vertebrates. As a result, vertebrates have a [[Blind spot (vision)|blind spot]].<ref name=SCM2005/>

=== Sex organs ===

Hydrostatic [[penis]]es have convergently evolved at least six times in male [[amniote]]s. In these species, males [[Copulation (zoology)|copulate]] with females and [[Internal fertilization|internally fertilize]] their eggs. Similar [[intromittent organ]]s have evolved in invertebrates such as [[octopus]]es and [[gastropod]]s.<ref>{{Cite book |last=McGhee |first=George R. |url=https://www.google.com/books/edition/Convergent_Evolution/QwDSr1qdqXUC?hl=en&gbpv=1&pg=PA82&printsec=frontcover |title=Convergent Evolution: Limited Forms Most Beautiful |date=2011 |publisher=MIT Press |isbn=978-0-262-01642-1 |page=82}}</ref>

=== Flight ===

{{Further|Flying and gliding animals#Evolution and ecology of aerial locomotion}}

[[File:Homology.jpg|thumb|upright|Vertebrate wings are partly [[Homology (biology)|homologous]] (from forelimbs), but analogous as organs of flight in (1) [[pterosaurs]], (2) [[bat]]s, (3) [[birds]], evolved separately.]]

[[Birds]] and [[bat]]s have [[homology (biology)|homologous]] limbs because they are both ultimately derived from terrestrial [[tetrapod]]s, but their flight mechanisms are only analogous, so their wings are examples of functional convergence. The two groups have independently evolved their own means of powered flight.  Their wings differ substantially in construction. The bat wing is a membrane stretched across four extremely elongated fingers and the legs. The airfoil of the bird wing is made of [[feather]]s, strongly attached to the forearm (the ulna) and the highly fused bones of the wrist and hand (the [[carpometacarpus]]), with only tiny remnants of two fingers remaining, each anchoring a single feather. So, while the wings of bats and birds are functionally convergent, they are not anatomically convergent.<ref name=BerkeleyHomologyAnalogy>{{cite web |title=Homologies and analogies |url=http://evolution.berkeley.edu/evolibrary/article/evo_09 |publisher=University of California Berkeley |access-date=2017-01-10 |archive-url=https://web.archive.org/web/20161119095845/http://evolution.berkeley.edu/evolibrary/article/evo_09 |archive-date=2016-11-19 |url-status=live }}</ref><ref>{{cite web |title=Plant and Animal Evolution |url=http://sci.waikato.ac.nz/evolution/Homology.shtml |publisher=University of Waikato |access-date=2017-01-10 |archive-url=https://web.archive.org/web/20170318123517/http://sci.waikato.ac.nz/evolution/Homology.shtml |archive-date=2017-03-18 |url-status=live }}</ref> Birds and bats also share a high concentration of [[cerebroside]]s in the skin of their wings. This improves skin flexibility, a trait useful for flying animals; other mammals have a far lower concentration.<ref>{{Cite journal |last1=Ben-Hamo |first1=Miriam |last2=Muñoz-Garcia |first2=Agustí |last3=Larrain |first3=Paloma |last4=Pinshow |first4=Berry |last5=Korine |first5=Carmi |last6=Williams |first6=Joseph B. |date=June 2016 |title=The cutaneous lipid composition of bat wing and tail membranes: a case of convergent evolution with birds |journal=Proc. R. Soc. B |volume=283 |issue=1833 |page=20160636 |doi=10.1098/rspb.2016.0636 |pmid=27335420 |pmc=4936036 }}</ref> The extinct [[pterosaur]]s independently evolved wings from their fore- and hindlimbs, while [[insect]]s have [[insect wing|wings]] that evolved separately from different organs.<ref>{{cite book |last=Alexander |first=David E. |title=On the Wing: Insects, Pterosaurs, Birds, Bats and the Evolution of Animal Flight |url=https://books.google.com/books?id=H6xUCgAAQBAJ&pg=PT28 |year=2015 |publisher=Oxford University Press |isbn=978-0-19-999679-7 |page=28 |access-date=2017-01-21 |archive-url=https://web.archive.org/web/20170214224338/https://books.google.com/books?id=H6xUCgAAQBAJ&pg=PT28 |archive-date=2017-02-14 |url-status=live }}</ref>

[[Flying squirrel]]s and [[sugar glider]]s are much alike in their mammalian body plans, with gliding wings stretched between their limbs, but flying squirrels are placentals while sugar gliders are marsupials, widely separated within the mammal lineage from the placentals.<ref>{{cite web |title=Analogy: Squirrels and Sugar Gliders |url=http://evolution.berkeley.edu/evolibrary/article/analogy_02 |publisher=University of California Berkeley |access-date=2017-01-10 |archive-url=https://web.archive.org/web/20170127120055/http://evolution.berkeley.edu/evolibrary/article/analogy_02 |archive-date=2017-01-27 |url-status=live }}</ref>

[[Hummingbird hawk-moth]]s and [[hummingbird]]s have evolved similar flight and feeding patterns.<ref name="herrera">{{cite journal |last1=Herrera |title=Activity pattern and thermal biology of a day-flying hawkmoth (''Macroglossum stellatarum'') under Mediterranean summer conditions |journal=Ecological Entomology |volume=17 |pages=52–56 |year=1992 |doi=10.1111/j.1365-2311.1992.tb01038.x |first1=Carlos M.|issue=1 |bibcode=1992EcoEn..17...52H |hdl=10261/44693 |s2cid=85320151 |hdl-access=free }}</ref>

=== Insect mouthparts ===

Insect mouthparts show many examples of convergent evolution. The mouthparts of different insect groups consist of a set of [[homology (biology)|homologous]] organs, specialised for the dietary intake of that insect group. Convergent evolution of many groups of insects led from original biting-chewing mouthparts to different, more specialised, derived function types. These include, for example, the [[proboscis]] of flower-visiting insects such as [[bee]]s and [[flower beetle]]s,<ref name="Krenn-2005">{{cite journal |last1=Krenn |first1=Harald W. |last2=Plant |first2=John D. |last3=Szucsich |first3=Nikolaus U. |year=2005 |title=Mouthparts of flower-visiting insects |journal=Arthropod Structure & Development |volume=34 |issue=1 |pages=1–40 |doi=10.1016/j.asd.2004.10.002}}</ref><ref name="Krenn-2011">{{cite journal |last1=Bauder |first1=Julia A.S. |last2=Lieskonig |first2=Nora R. |last3=Krenn |first3=Harald W. |year=2011 |title=The extremely long-tongued Neotropical butterfly Eurybia lycisca (Riodinidae): Proboscis morphology and flower handling |journal=Arthropod Structure & Development |volume=40 |issue=2 |pages=122–7 |doi=10.1016/j.asd.2010.11.002|pmid=21115131 |pmc=3062012 |bibcode=2011ArtSD..40..122B }}</ref><ref name="Krenn-2012-1">{{cite journal |last1=Wilhelmi |first1=Andreas P. |last2=Krenn |first2=Harald W. |year=2012 |title=Elongated mouthparts of nectar-feeding Meloidae (Coleoptera) |journal=Zoomorphology |volume=131 |issue=4 |pages=325–37 |doi=10.1007/s00435-012-0162-3|s2cid=9194699 }}</ref> or the biting-sucking mouthparts of blood-sucking insects such as [[flea]]s and [[mosquito]]s.

=== Opposable thumbs ===

[[Opposable thumb]]s allowing the grasping of objects are most often associated with [[primates]], like humans and other apes, monkeys, and lemurs. Opposable thumbs also evolved in [[giant pandas]], but these are completely different in structure, having six fingers including the thumb, which develops from a wrist bone entirely separately from other fingers.<ref>{{cite web|title=When is a thumb a thumb?|url=http://evolution.berkeley.edu/evolibrary/article/analogy_06|website=Understanding Evolution|access-date=2015-08-14|archive-url=https://web.archive.org/web/20151016133905/http://evolution.berkeley.edu/evolibrary/article/analogy_06|archive-date=2015-10-16|url-status=live}}</ref>

=== Primates ===

{{Further|Human skin color#Genetics of skin color variation}}

{| style="border-collapse: collapse" class="floatleft" width=222px
|- 
|style="padding:0;margin:0"| {{CSS image crop|Image=Veronika Loncká.jpg|bSize=73|cWidth = 74|cHeight = 65|oTop = 0|oLeft =0}}
|style="padding:0;margin:0"| {{CSS image crop|Image=Angela Bassett by Gage Skidmoe.jpg|bSize=84|cWidth = 74|cHeight = 65|oTop = 10|oLeft =0}}
|style="padding:0;margin:0"| {{CSS image crop|Image=(미쓰와이프) 제작기영상 엄정화 3m3s.jpg|bSize=104|cWidth = 74|cHeight = 65|oTop = 17|oLeft =17}}
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|colspan=3 style="padding:0;margin:0"|[[File:Convergent evolution human skin color map.svg|222px]] {{resize|90%|Despite the similar lightening of [[human skin color|skin colour]] after moving [[Out of Africa hypothesis|out of Africa]], different genes were involved in European (left) and East Asian (right) lineages.}}
|}

Convergent evolution in humans includes blue eye colour and light skin colour.<ref name="Edwards 2010"/> When humans migrated [[Out of Africa hypothesis|out of Africa]], they moved to more northern latitudes with less intense sunlight.<ref name="Edwards 2010"/> It was beneficial to them to have reduced [[human skin color|skin pigmentation]].<ref name="Edwards 2010"/> It appears certain that there was some lightening of skin colour ''before'' European and East Asian lineages diverged, as there are some skin-lightening genetic differences that are common to both groups.<ref name="Edwards 2010"/> However, after the lineages diverged and became genetically isolated, the skin of both groups lightened more, and that additional lightening was due to ''different'' genetic changes.<ref name="Edwards 2010">{{cite journal |last1=Edwards |first1=M. |display-authors=etal |title=Association of the OCA2 Polymorphism His615Arg with Melanin Content in East Asian Populations: Further Evidence of Convergent Evolution of Skin Pigmentation |journal=PLOS Genetics |date=2010 |doi=10.1371/journal.pgen.1000867 |volume=6 |issue=3 |pages=e1000867 |pmid=20221248 |pmc=2832666 |doi-access=free }}</ref>

{| style="border-collapse: collapse" class="floatright"  width=220px
|-
! colspan=2|Humans
! colspan=2|Lemurs
|- 
|style="padding:0;margin:0"| {{CSS image crop|Image=A_blue_eye.jpg|bSize=100|cWidth = 50|cHeight = 50|oTop = 25|oLeft =25}}
|style="padding:0;margin:0"| {{CSS image crop|Image=Eye_See_You_(2346693372).jpg|bSize=130|cWidth = 50|cHeight = 50|oTop = 8|oLeft =53}}
|style="padding:0;margin:0"| {{CSS image crop|Image=Eulemur_mongoz_(male_-_face).jpg |bSize=400|cWidth = 50|cHeight = 50|oTop = 130|oLeft =150}}
|style="padding:0;margin:0"| {{CSS image crop|Image=Blue-eyed_black_lemur.jpg|bSize=400|cWidth = 50|cHeight = 50|oTop = 100|oLeft =133}}
|-
|colspan=4 style="padding:0;margin:0"|{{resize|90%|Despite the similarity of appearance, the genetic basis of blue eyes is different in humans and [[lemur]]s.}}
|}

[[Lemurs]] and [[humans]] are both primates. Ancestral primates had brown eyes, as most primates do today. The genetic basis of blue eyes in humans has been studied in detail and much is known about it. It is not the case that one [[Locus (genetics)|gene locus]] is responsible, say with brown dominant to blue [[eye colour]]. However, a single locus is responsible for about 80% of the variation. In lemurs, the differences between blue and brown eyes are not completely known, but the same gene locus is not involved.<ref>{{cite journal |last1=Meyer |first1=W. K.| display-authors=etal |title=The convergent evolution of blue iris pigmentation in primates took distinct molecular paths |journal=American Journal of Physical Anthropology |date=2013 |volume=151 |issue=3 |pages=398–407 |doi=10.1002/ajpa.22280 |pmid=23640739 |pmc=3746105}}</ref>{{clear left}}