Editing Penguin (section)

====Relationship to other bird orders====
Penguin ancestry beyond ''[[Waimanu]]'' remains unknown and not well-resolved by molecular or morphological analyses. The latter tend to be confounded by the strong adaptive [[Autapomorphy|autapomorphies]] of the Sphenisciformes; a sometimes perceived fairly close relationship between penguins and [[grebe]]s is almost certainly an error based on both groups' strong diving adaptations, which are [[homoplasies]]. On the other hand, different [[DNA sequence]] datasets do not agree in detail with each other either.

[[File:Spheniscus humboldti -swimming -aquarium-8a.jpg|thumb|Humboldt penguins in an aquarium. The penguin is an accomplished swimmer, having [[Flipper (anatomy)|flippers]] instead of wings.]]
What seems clear is that penguins belong to a clade of [[Neoaves]] (living birds except for [[paleognath]]s and [[fowl]]) that comprises what is sometimes called "[[Aequornithes|higher waterbirds]]" to distinguish them from the more ancient [[waterfowl]]. This group contains such birds as [[stork]]s, [[Rallidae|rails]], and the [[seabird]]s, with the possible exception of the [[Charadriiformes]].<ref>{{Cite journal|doi=10.1554/04-235 |url=http://biology-web.nmsu.edu/houde/Parallel_radiations.pdf |pmid=15612298 |title=Parallel Radiations in the Primary Clades of Birds |journal=Evolution |volume=58 |issue=11 |pages=2558–73 |year=2004 |last1=Fain |first1=M. G. |last2=Houde |first2=P. |bibcode=2004Evolu..58.2558F |s2cid=1296408 |url-status=dead |archive-url=https://web.archive.org/web/20130407204436/http://biology-web.nmsu.edu/houde/Parallel_radiations.pdf |archive-date=April 7, 2013 }}</ref>

Inside this group, penguin relationships are far less clear. Depending on the analysis and dataset, a close relationship to [[Ciconiiformes]]<ref name="Slack"/> or to [[Procellariiformes]]<ref name="Baker"/> has been suggested. Some think the penguin-like [[Plotopteridae|plotopterids]] (usually considered relatives of [[cormorant]]s and [[anhinga]]s) may actually be a sister group of the penguins and those penguins may have ultimately shared a common ancestor with the [[Pelecaniformes]] and consequently would have to be included in that order, or that the plotopterids were not as close to other pelecaniforms as generally assumed, which would necessitate splitting the traditional Pelecaniformes into three.<ref>{{Cite journal| doi = 10.1111/j.1439-0469.2004.00291.x|url=http://www.senckenberg.de/files/content/forschung/abteilung/terrzool/ornithologie/plotopteridae.pdf| title = Tertiary plotopterids (Aves, Plotopteridae) and a novel hypothesis on the phylogenetic relationships of penguins (Spheniscidae)| journal = Journal of Zoological Systematics and Evolutionary Research| volume = 43| pages = 61–71| year = 2005| last1 = Mayr| first1 = G.| access-date = July 8, 2006| archive-url=https://web.archive.org/web/20061013085236/http://www.senckenberg.de/files/content/forschung/abteilung/terrzool/ornithologie/plotopteridae.pdf| archive-date = October 13, 2006| url-status = live}}</ref>

A 2014 analysis of whole genomes of 48 representative bird species has concluded that penguins are the [[sister group]] of Procellariiformes,<ref name = "Jarvis2014">{{Cite journal| doi = 10.1126/science.1253451| pmid = 25504713|url=https://pgl.soe.ucsc.edu/jarvis14.pdf| title = Whole-genome analyses resolve early branches in the tree of life of modern birds| journal = Science| volume = 346| issue = #6215| pages = 1320–1331| date = 2014| last1 = Jarvis| first1 = E. D.| author1-link = Erich Jarvis| last2 = Mirarab| first2 = S.| last3 = Aberer| first3 = A. J.| last4 = Li| first4 = B.| last5 = Houde| first5 = P.| last6 = Li| first6 = C.| last7 = Ho| first7 = S. Y. W.| last8 = Faircloth| first8 = B. C.| last9 = Nabholz| first9 = B.| last10 = Howard| first10 = J. T.| last11 = Suh| first11 = A.| last12 = Weber| first12 = C. C.| last13 = Da Fonseca| first13 = R. R.| last14 = Li| first14 = J.| last15 = Zhang| first15 = F.| last16 = Li| first16 = H.| last17 = Zhou| first17 = L.| last18 = Narula| first18 = N.| last19 = Liu| first19 = L.| last20 = Ganapathy| first20 = G.| last21 = Boussau| first21 = B.| last22 = Bayzid| first22 = M. S.| last23 = Zavidovych| first23 = V.| last24 = Subramanian| first24 = S.| last25 = Gabaldon| first25 = T.| last26 = Capella-Gutierrez| first26 = S.| last27 = Huerta-Cepas| first27 = J.| last28 = Rekepalli| first28 = B.| last29 = Munch| first29 = K.| last30 = Schierup| first30 = M.| display-authors = 29| pmc = 4405904| bibcode = 2014Sci...346.1320J| hdl = 10072/67425| access-date = August 28, 2015| archive-url=https://web.archive.org/web/20150224020622/http://pgl.soe.ucsc.edu/jarvis14.pdf| archive-date = February 24, 2015| url-status = dead}}</ref> from which they diverged about 60 million years ago (95% CI, 56.8–62.7).<ref name = "LiC2014">{{Cite journal | doi = 10.1186/2047-217X-3-27| title = Two Antarctic penguin genomes reveal insights into their evolutionary history and molecular changes related to the Antarctic environment| journal = GigaScience| volume = 3| issue = #1| pages = 27| date = December 12, 2014| last1 = Li | first1 = C. | last2 = Zhang | first2 = Y. | last3 = Li | first3 = J. | last4 = Kong | first4 = L. | last5 = Hu | first5 = H. | last6 = Pan | first6 = H. | last7 = Xu | first7 = L. | last8 = Deng | first8 = Y. | last9 = Li | first9 = Q. | last10 = Jin | first10 = L. | last11 = Yu | first11 = H. | last12 = Chen | first12 = Y. | last13 = Liu | first13 = B. | last14 = Yang | first14 = L. | last15 = Liu | first15 = S. | last16 = Zhang | first16 = Y. | last17 = Lang | first17 = Y. | last18 = Xia | first18 = J. | last19 = He | first19 = W. | last20 = Shi | first20 = Q. | last21 = Subramanian | first21 = S. | last22 = Millar | first22 = C. D. | last23 = Meader | first23 = S. | last24 = Rands | first24 = C. M. | last25 = Fujita | first25 = M. K. | last26 = Greenwold | first26 = M. J. | last27 = Castoe | first27 = T. A. | last28 = Pollock | first28 = D. D. | last29 = Gu | first29 = W. | last30 = Nam | first30 = K. | display-authors = 29 | pmid=25671092 | pmc=4322438| doi-access = free}}</ref>

The distantly related [[Puffin]]s, which live in the North Pacific and North Atlantic, developed similar characteristics to survive in the Arctic and sub-Arctic environments. Like the penguins, puffins have a white chest, black back and short stubby wings providing excellent swimming ability in icy water. But, unlike penguins, puffins can fly, as flightless birds would not survive alongside land-based predators such as polar bears and foxes; there are no such predators in the Antarctic. Their similarities indicate that similar environments, although at great distances, can result in similar evolutionary developments, i.e. [[convergent evolution]].<ref>{{Cite book |title=Introduction to Marine Biology |last=Karleskint |first=George |publisher=Cengage Publishing |year=2012 |isbn=978-1285402222 |pages=30 |url=https://books.google.com/books?id=9fEKAAAAQBAJ |access-date=August 15, 2018 |archive-date=July 21, 2020 |archive-url=https://web.archive.org/web/20200721052701/https://books.google.com/books?id=9fEKAAAAQBAJ |url-status=live }}</ref>