Editing Convergent evolution (section)

===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>