List of examples of convergent evolution

[Note: This is the EDU Community version of the Wikipedia page, List of examples of convergent evolution].

Overview

Convergent evolution (CE) is evidence or argument for physical attractors in the phase space of dynamical possibility which guide and constrain contingently adaptive evolutionary processes into statistically predictable future-specific structure or function, in a variety of physical and informational environments. When we look at evolutionary history, the dynamics of several species morphology or function is seen to converge to particular "archetypal forms and functions" in a variety of environments.

Such attractors have been called deep structure, guiding evolutionary process in predictable ways, regardless of local environmental differences. Organismic development depends on specific initial conditions (developmental genes in the "seed"), the emergence of hierarchies of modular structure and function in the unfolding organism, and persistent constancies (physical and chemical laws, stable biomes) in the environment. Likewise, some examples of convergent evolution may be best characterized as ecological, biogeographical, stellar-planetary, or universal evolutionary development (ED) if their emergence can modeled, after adjusting for observer selection, to depend on specific universal initial conditions, emergent hierarchies, and environmental constancies.

A famous example of convergence is found in eyes, which appear to have evolved on Earth from different genetic lineages to work similarly (function) in all species, and in the case of camera eyes, to also look very similar (form) in both vertebrate and invertebrate species, like humans and octopi. One can easily advance the argument that, in universes of our type, eyes, though first created by a process of evolutionary contingency, become an archetype, a kind of general optimization for almost all eye-possessing multicelluar species in Earth-like environments, once they exist. Presumably, the previously rapidly-changing "evolutionary" gene groups that led to eye creation become part of the "developmental" genetic toolkit for eye-possessing species. Such developmental features should become increasingly strongly conserved and eventually, due to path dependency and emergent hierarchies, incapable of being changed without preventing development itself. Proving such genetic convergence arguments with evidence and theory is of course more difficult, yet it is a fertile area of investigation today.

For the best website on convergent evolution in biological systems that we know of, see Simon Conway-Morris's team's excellent Map of Life: Convergent Evolution Online.

Less-optimizing convergence (LOC) vs. optimizing convergence (OC)

In our mostly chaotic, contingent, and deeply nonlinear universe, we can predict that many, perhaps even the vast majority, of examples of CE will not be driven by the evolving system's discovery of some hidden general optimization function, like the discovery of the eye archetype. To understand convergence, we will need some kind of general optimization theory. Let's consider two necessary features of that theory now.

1. We can predict that any optimization that occurs must be on a continuum, from highly-optimizing convergence, which we will refer to simply as optimizing convergence (OC), conferring advantage in all the most competitive and complex environments, to a wide variety of other cases, which we can refer to collectively as less-optimizing convergence (LOC). LOC cases would include convergence that offers only some temporary or local adaptive advantage, to just a few specific species, or in some subset of specialized or less-complex environments, convergence that offers no advantage, or convergence that is deleterious but not fatal. Names for a few general classes of LOC cases have been offered by scholars, including passive convergence, parallel evolution, etc.
2. Optimizing convergence can occur via both physical and informational processes. Physically, we might see greater efficiency of employment of physical resources, as in Bejan's constructal law, or greater density of employment of physical resources for offense or defense, the escalation hypothesis (Vermeij 1987). Informationally, we might see efficiency or density gains via informational substitution for physical processes, what Fuller called ephemeralization, or greater general intelligence (modeling ability), greater immunity, or a more useful collective morality, offering more general and persistent adaptation to a wider range of environments than previous strategies. Intelligence also offers the ability to modify environments to suit the organism, what biologists call niche-construction, as humans extensively do today. To understand OC, we will need a theory of optimization that tells us when a physical or informational advantage is likely to be more generally adaptive, particularly in the most complex, competitive and rapidly-changing environments. We also need to know whether there are any other paths that can lead, in a competitive timeframe, toward a competitively superior new form of adaptiveness. If not, then we may have discovered a developmental portal, a global optimum that represents a bottleneck, a singular pathway toward greater adaptation at the leading edge of local complexity. Organic chemistry, RNA, photosynthesis, and oxidative phosphorylation are all potential examples of portals that all universal life must pass through first, on the way toward greater adaptive complexity. They may be the only global optima on their landscapes, at the relevant timeframes, that will allow the creation of vastly greater adaptive complexity. For more on developmental portals, see our page on evolutionary development.

Consider eyes again. For their time, eyes were "the leading edge" of general optimization, for animals, in the most morphologically complex (multicellular) environments on Earth. Andrew Parker's light switch theory (In the Blink of an Eye, 2003) proposes that the development of vision in Precambrian animals directly caused the Cambrian explosion. This is a fascinating theory, implying an intelligence-driven optimization and acceleration of morphological and functional complexity. It proposes that eyes created a vastly more competitive, discriminatory, and intelligent evolutionary environment (set of selection pressures) in multicellular evolutionary space. Once they emerged, it is easy to argue that all visible animals in that intelligence-leading environment needed eyes, or other highly effective defensive strategies, to survive. Intelligence, in this case, and perhaps generally, appears to be part of a physical and informational optimization function, in the most morphologically and functionally complex environments.

Many other examples of OC can be proposed, in the most physically and informationally complex, and rapidly changing, environments on Earth, including the necessary emergence of eukaryotes, oxidative phosphorylation, multicellularity, nervous systems, bilateral symmetry, jointed limbs, opposable thumbs, tool and language use on land (much faster-improving than aqueous environments), culture, and technology, including machine intelligence. Future science will need better theories of complexity, complexification, and optimization, to deeply understand convergence, and to distinguish the much greater variety of examples of less-optimized convergence from the most highly optimized forms.

Optimizing convergence as evolutionary development (ED)

Embryogenesis is an evo devo process.

When convergence is viewed from the perspective not of the evolving species, but from some larger systems level (the biogeography, the planet, the universe) we can view optimizing convergent evolution as a process of not simply evolution, but of evolutionary development (ED).

Evo-devo biology offers us the canonical example of evolutionary development, at the organismic system level. In organisms, most molecular and cellular processes operate chaotically, contingently, and locally adaptively, a process with many dynamical similarities to species evolution. Yet a special few of these molecular and cellular processes, driven by developmental genes and environmental constancies, are chaos-reducing, convergent, constraining, and statistically predictable, or developmental. We can generalize from organismic evo-devo to construct a general theory of ED for any replicating system.

When we claim a convergence process is an example of ED, we are not only claiming that some kind of general optimization is occurring. We are also claiming that some kind of evolutionary developmental process, with both "random" and creative evolutionary search, and predictable convergence, directionality, hierarchy, modularity, life cycle, and perhaps other features found in biological development, is being followed, at some larger systems level. We see both mostly stochastic and contingent processes, along with a few convergent and hierarchical processes, in such evolutionary and developmental phenomena as embryogenesis. Evo devo models assume such a process is going on even at the universal scale, and thus that some examples of convergence can be better understood in complex systems theory as not simply evolution, but evolutionary development.

• Ecology offers several examples of not only evolutionary but apparent developmental change. When we look above the level of species change to ecologies, we can identify predictable patterns of ecological change, including ecological succession.
• Biogeography offers more examples. When we look above ecologies to biogeography, we find scaling laws, like Copes rule, and biogeographic laws like Foster’s rule and Bergmann’s rule, with their predictable processes of convergent and optimizing CE, or evolutionary development. The famous convergence of form seen in placental and marsupial mammals, on separate continents, offers another example of not just evolution, but biogeographic ED. For many more examples, including convergence in intelligence traits, see Conway-Morris (2004,2015) and McGhee (2011) and our list of examples of convergent evolution in species morphology and function below.
• Culture change offers more examples. When we look above individual cultures and do cross-cultural comparisons, we find many examples of developmental features at the leading edge of competitiveness, including inventions like fire, language, stone tools, clubs, sticks, levers, written language, hydraulic empires for our first great cities, wheels, electricity, computers. etc. In each of these cases, a high-order convergence has occurred. These and other specific examples of cultural change look not only evolutionary, but evolutionary developmental (ED). Once they exist, there's no going back, for any culture seeking to stay on the leading edge of physical and informational complexification, and general adaptiveness. We also find many examples of constraint laws that operate in social and economic systems, like physicist and EDU scholar Adrian Bejan’s constructal law, and more generally, the least action principle.
• Stellar-Planetary change offers more examples. When we look above human culture to our planet and its star, astrophysical theory tells us that the way stars have replicated, and chemically complexified, through three different populations over billions of years, has been not only evolutionary (a variety of randomly arrived at star and planet types and distributions) but evolutionary developmental, involving a progressive drive to complexification in a predictable subset of types. Many astrobiologists and planetologists argue that a subset of chaotic and nonlinear (“evolutionary”) stellar-planetary change has reliably led, with high probability and massive parallelism, to M-class stars and Earth-like planets that are biochemically and geohomeostatically ideal for the development of archaebacterial (geothermal vent) life, and from there to prokaryotes and eukaryotes. See Nick Lane's The Vital Question (2016) for one such story.
• Universal change offers more examples. When we look beyond stars to galaxies (which do not replicate within this universe) and to the universe as a system, several cosmologists propose that it has not only much change that is evolutionary (random, contingent, experimental), but a large subset that appears developmental. If the universe and its galaxies are a replicative system in the multiverse, as some cosmologists have proposed, such special initial conditions and constancies may have themselves self-organized in an iterative and selective process, just as biological developmental parameters have self-organized, in biological systems over multiple replications. For more on the latter idea, see our wiki page cosmological natural selection (fecund universes). The fine-tuned universe hypothesis also offers one of several examples that the initial conditions of our universe seem self-organized for the emergence of internal complexity and its persistence over billions of years. As in biological genes, only a handful of which are developmental, highly conserved, and finely-tuned, only a handful of these universal parameters seem improbably finely tuned, to a degree far beyond that we would expect through obvious observer-selection effects. See Martin Rees, Just Six Numbers, 1999 for one such account.

If universal evolutionary development is occurring, future science must show that each successive environment in the developmental hierarchy inherits certain initial conditions and physical constancies from the environment that preceded it, back to the birth of the universe, and that some of these initial conditions and constancies act to predictably constrain the future dynamics of each successive environment, to some degree. These constraints have been called developmental portals by some scholars. M-class stars and organic chemistry may be necessary portals to planets capable of generating life. Fats, proteins, and nucleic acids may be necessary portals to cells. Eyes may be necessary portals to higher nervous systems, etc. These portals must also work together to periodically produce a metasystem transition (a higher level of order or control), a new level of ED hierarchy.

Another example of predictable developmental signal, across all of these environments, may be the ever-faster complexification we see in the historical record of the most physically and informationally complex locations in our universe, since the emergence of M-class stars, Earth-like planets, and almost simultaneously, on our planet, life. This acceleration was famously summarized in Carl Sagan's metaphor of the Cosmic Calendar. Ever since August, on this calendar metaphor, leading-edge complexity environments have become exponentially faster, more complex, and more intelligent, on average, on Earth. Sagan said this phenomenon, which we can call acceleration studies, was an understudied area of science, in need of better understanding. See Sagan's The Dragons of Eden (1977) for his original account. It our hope that better models of early universe, astrophysical, chemical, biological, psychological, social, economic, technological, and other evolutionary development will help us understand our universe's emergence record of ever faster and more physically- and informationally-complex local environments.

For a deeper introduction to this topic, see our wiki page, evolutionary development.

Examples of convergent evolution (roughly scale and complexity ranked at each level of scale)

Convergent evolution—the evolutionary emergence of similar traits (forms or functions) in unrelated lineages—is rife in nature, as illustrated by the examples below. Convergence occasionally even creates cryptic species, organisms so similar in appearance that their uniqueness can only be discerned by discovering their separate breeding lineages, or analyzing their genes.

The most common cause of convergence is a similar evolutionary biome, as similar environments select for similar traits in many species occupying the same ecological niche, even when those species are only distantly related. Environmental convergence causes can be both physical and informational in nature. Species convergence on the archetypal shape of fish fins seems a primarily due to physical functional constraints (streamlining reduces drag in water). The convergence on eyes, of which there are eight major optical types in animals, apparently happened at least a dozen times in evolutionary history, presumably due to informational functional constraints (seeing allows better navigation of the environment). Synapses, which emerged at least three independent times, clearly offer additional informational advantages (storing memories, thinking), in adapting to complex and competitive environments. Certain forms of convergence (eyes, synapses) are particularly advantageous for surviving in informationally-complex environments, and completing against other informationally-complex species. Not simply local adaptation, but some general optimization function may exist for such environments.

Cultural convergence on particular human-technological traits (forms and functions), as seen in the use and inevitable improvement and radiation of opposable thumbs, rocks, clubs, language, levers, ropes, pulleys, wheels, math, plant and animal domestication, architecture, cities, warmaking technologies, engines, electricity, computers, etc. in cultural evolution offers clear physical and informational advantages to the humans using those technologies, in sufficiently complex environments. Again, some general optimization function, involving convergence in environments of escalating innovation and competition, seems likely to exist. Models of social development, using traits like energy capture per capita, information technology, war-making capacity, and organization, offer convergence variables that are proposed to predict the competitiveness and longevity of social groups. We are early in such work, but it seems the direction we must go, to better understand cultural convergence.

Unlike Wikipedia's list of convergence examples, which are offered in no particularly useful order, as they adhere to the standard "random" and "blind" view of evolutionary process, we list our collection of convergence examples from smaller to larger in scale (molecular to ecosystem) and from less physically and informationally complex (in morphology, function, and intelligence) to more complex--a much more useful categorization scheme. While standard evolutionary theory continues to dismiss the idea that our universe appears biased to produce accelerating complexity, there is an obvious trend of accelerating complexification in the most complex of Earth's environments. In our view, this predictable complexification can be understood best by proposing that our universe appears not only to be evolving, but to be developing, a model of change we call evolutionary development.

In proteins, including enzymes and biochemical pathways

• The existence of distinct families of carbonic anhydrase is believed to illustrate convergent evolution.
• The use of (Z)-7-dodecen-1-yl acetate as a sex pheromone by the Asian elephant (Elephas maximus) and by more than 100 species of Lepidoptera.
• The independent development of the catalytic triad in serine proteases independently with subtilisin in prokaryotes and the chymotrypsin clan in eukaryotes.
• The repeated independent evolution of nylonase in two different strains of Flavobacterium and one strain of Pseudomonas.
• The biosynthesis of plant hormones such as gibberellin and abscisic acid by different biochemical pathways in plants and fungi.
• ABAC is a database of convergently evolved protein interaction interfaces. Examples comprise fibronectin/long chain cytokines, NEF/SH2, cyclophilin/capsid proteins. Details are described here.
• The independent development of three distinct hydrogenases exemplifies convergent evolution.
• The protein prestin that drives the cochlea amplifier and confers high auditory sensitivity in mammals, shows numerous convergent amino acid replacements in bats and dolphins, both of which have independently evolved high frequency hearing for Animal echolocation|echolocation. This same signature of convergence has also been found in other genes expressed in the mammalian cochlea.

In bacteria

• The archaeal bacteria in the family Halobacteriaceae, and the non-archael bacterium Salinibacter ruber are both halophiles adapted to live in very high salt environments.
• Bioluminescence: A symbiotic partnerships with light-emitting bacteria developed many times independently in deep-sea fish, jellyfish, and in fireflies and glow worms.

In functional anatomy (general)

• Venomous sting: To inject poison with a hypodermic needle, a sharp pointed tube, has emerged and persisted independently 10+ times: jellyfish, spiders, scorpions, centipedes, various insects, cone shell, snakes, stingrays, stonefish, the male duckbill platypus, and stinging nettles plant.
• Parthenogenesis: Some lizards and insects have independent the capacity for females to produce live young from unfertilized egg (biology)|eggs. Some species are entirely female.

In functional anatomy (nervous systems)

• The notochords in chordates are like the stomochords in hemichordates.
• Eyes, of which there are eight major optical types in animals, apparently emerged at least a dozen independent ways and times in evolutionary history, presumably due to their impressive informational functional constraints (seeing allows predictably superior navigation of the environment, in almost all environments).
• Synapses emerged at least three independent times, with three somewhat different molecular-genetic structures, in ctenophora (comb jellies), cnidaria (jellyfish) and bilateria (bilaterally symmetric animals). Synapses offer constraining informational advantages (storing memories, thinking), in adapting to complex and competitive environments.
• Bioluminescence: A symbiotic partnerships with light-emitting bacteria developed many times independently in deep-sea fish, jellyfish, and in fireflies and glow worms.

In plants

• Leaves have evolved multiple times - see Evolutionary history of plants.
• Spine (botany)|Prickles, Spine (botany)|thorns and Spine (botany)|spines are all modified plant tissues that have evolved to prevent or limit herbivory, these structures have evolved independently a number of times.
• Stimulant toxins: Plants which are only distantly related to each other, such as coffee and tea, produce caffeine to deter predators.
• The aerial rootlets found in ivy (Hedera) are similar to those of the Hydrangea petiolaris|climbing hydrangea (Hydrangea petiolaris) and some other vines. These rootlets are not derived from a common ancestor but have the same function of clinging to whatever support is available.
• Flowering plants (Delphinium, Aerangis, Tropaeolum and others) from different regions form tube-like spur (botany)|spur which contains nectar (that's why insect from one place sometimes can feed on plant from other which has such structure like the flower which is the traditional source of food for the animal).
• Both some dicots (Anemone) and monocots (Trillium) in inhospitable environments are able to form underground organs such as corms, bulbs and rhizomes for reserving of nutrition and water till the conditions become better.
• Insectivorous plants: Nitrogen-deficient plants have in at least 7 distinct times become insectivorous, like: flypaper traps\sundew, spring traps-Venus fly trap, and pitcher traps in order to capture and digest insects to obtain scarce nitrogen.
• Similar-looking rosette succulents have arisen separately among plants in the families Asphodelaceae (formerly Liliaceae) and Crassulaceae.
• The Orchids, the Birthwort family and Stylidiaceae have evolved independently the specific organ known as gynostemium, more popular as gynostemium|column.
• The Euphorbia of deserts in Africa and southern Asia, and the Cactaceae of the New World deserts have similar modifications (see picture below for one of many possible examples).
• Sunflower: some types of Sunflower and Pericallis are due to convergent evolution.

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  Euphorbia obesa

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  Astrophytum asterias

In animals

Arthropods

Pill bugs look like pill millipedes, but are actually wood lice that have converged on the same defenses, until they are difficult to tell apart

• Assassin spiders comprise two lineages that evolved independently. They have very long necks and fangs proportionately larger than those of any other spider, and they hunt other spiders by snagging them from a distance.
• The smelling organs of the terrestrial coconut crab are similar to those of insects.
• Pill bugs and pill millipedes have evolved not only identical defenses, but are even difficult tell apart at a glance.
• Silk: Spiders, silk moths, larval caddis flies, and the weaver ant all produce silken threads.
• The praying mantis body type – raptorial forelimb, prehensile neck, and extraordinary snatching speed - has evolved not only in mantid insects but also independently in neuropteran insects Mantispidae.
• Agriculture: Some kinds of ants, termites, and ambrosia beetles have for a long time cultivated and tend fungi for food. These insects sow, fertilize, and weed their crops. A damselfish also takes care of red algae carpets on its piece of reef; the damselfish actively weeds out invading species of algae by nipping out the newcomer.

Molluscs

• Bivalves and the gastropods in the family Juliidae have very similar shells.
• There are limpet-like forms in several lines of gastropods: "true" limpets, pulmonate siphonariid limpets and several lineages of pulmonate freshwater limpets.
• Cuttlefish show similarities between cephalopod (nautili, octopods and squid) and vertebrate (Mammalia...) eyes.
• Swim bladders – Buoyant bladders independently evolved in fishes, female octopus and siphonophores such as the Portuguese Man o' War.
• The phylum Mollusca members such as bivalves, and phylum Brachiopoda members, the brachiopods aka lampshells, independently evolved paired hinged shells for protection. The anatomy of their soft body parts is so dissimilar, however, that they are classified in separate, independent phyla. Biologists think that clams are more closely related to earthworms than they are to brachiopods.
• Jet propulsion in squids and in scallops: these two groups of mollusks have very different ways of squeezing water through their bodies in order to power rapid movement through a fluid. (Dragonfly larvae in the aquatic stage also use an anal jet to propel them, and Jellyfish have used jet propulsion for a very long time.)

Fish

• Goby dorsal finned like the lumpsuckers, yet they are not related.
• Sandlance fish and chameleons have independent eye movements and focusing by use of the cornea.
• Cichlids of South America and the "Centrarchidae|sunfish" of North America are strikingly similar in morphology, ecology and behavior.
• The Peacock Bass and Largemouth Bass are excellent examples.
• The Antifreeze_proteins#Evolution|Antifreeze protein of fish in the arctic and Antarctic, came about independently.
• Eel form are independent in the North American brook lamprey, neotropical eels, and the African spiny eel.
• Stickleback fish, there is widespread convergent evolution in Sticklebacks.
• Flying fish can fly up to 400 m (1,300 ft) at speeds of more than 70 kilometres per hour (43 mph) at a maximum altitude of more than 6 m (20 ft), much like other flying birds, bats and other gliders.
• The Cleaner Wrasse Labroides dimidiatus of the Indian Ocean is a small, longitudinally-striped black and bright blue cleaning symbiosis|cleaner fish, just like the Cleaner Goby Elacatinus|Elacatinus evelynae of the Western Atlantic.

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  Cleaner wrasse Labroides dimidiatus servicing a Bigeye squirrelfish

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  Caribbean cleaning goby Elacatinus evelynae

Amphibians

• Plethodontid salamanders and Chameleons have evolved a harpoon-like tongue to catch insects.
• The Neotropical poison dart frog and the Mantella of Madagascar have independently developed similar mechanisms for obtaining alkaloids from a diet of mites and storing the toxic chemicals in skin glands. They have also independently evolved similar bright skin colors that warn predators of their toxicity (by the opposite of crypsis, namely aposematism).
• Caecilian are Lissamphibians that secondarly lost their limbs, resembling snakes

Prehistoric reptiles

• Ornithischian (bird-hipped) dinosaurs had a pelvis shape similar to that of birds, or avian dinosaurs, which evolved from saurischian (lizard-hipped) dinosaurs.
• The Heterodontosauridae evolved a tibiotarsus which is also found in modern birds. These groups aren't closely related.
• Ankylosaurs and glyptodont mammals both had spiked tails.
• Horned snouts independently is on non-related dinosaurs like ceratopsians and Triceratops, also Rhinoceros|rhinos and the brontotheres of the Cenozoic.
• Billed snouts on the duck-billed dinosaurs hadrosaurs strikingly convergent with ducks and duck-billed platypus.
• Ichthyosaurs a marine reptile of the Mesozoic era looked strikingly like dolphins.
• Beaks are independent in ceratopsian dinosaurs like Triceratops, birds and marine mollusks like squid and octopus.
• The Pelycosauria and the Ctenosauriscide beared striking resemblance to each other because they both had a sail-like fin on their back. The Pelycosaurs are more closely related to mammals while the Ctenosauriscids are closely related to pterosaurs and dinosaurs. Also, the Spinosaurids had sail-like fins on their backs, when they were not closely related to either.
  • Also, Acrocanthosaurus and Ouranosaurus, which are not closely related to either Pelycosaurs, Ctenosauriscids or Spinosaurids, also had similar, but thicker, spines on their vertebrae, and thus have humps, like the unrelated, mammalian camels and bison.
• Noasaurus, Baryonyx, and Megaraptor, all unrelated, all had an enlarged hand claw that were originally thought to be placed on the foot, as in dromaeosaurs. A similarly modified claw (or in this case, finger) is on the hand of Iguanodon.
• The Ornithopods had feet and beaks that resembled that of birds, but are only distantly related.
• Three groups of dinosaurs, the Tyrannosauridae, Ornithomimosauria, and the Troodontidae, all evolved an arctometatarsus, independently.

Extant reptiles

• The thorny devil (Moloch horridus) is similar in diet and activity patterns to the Texas horned lizard (Phrynosoma cornutum), although the two are not particularly closely related.
• Modern Crocodilians resemble prehistoric phytosaurs, champsosaurs, certain labyrinthodont amphibians, and perhaps even the early Cetacea|whale Ambulocetus. The resemblance between the crocodilians and phytosaurs in particular is quite striking; even to the point of having evolved the graduation between narrow- and broad-snouted forms, due to differences in diet between particular species in both groups.
• The body shape of the prehistoric fish-like reptile Opthalmosaurus is similar to those of other ichthyosaurians, dolphins (aquatic mammals), and tuna (scombrid fish).
• Acanthophis|Death Adders strongly resemble true Viperidae|vipers, but are Elapidae|elapids.
• The Glass Snake is actually a lizard but is mistaken as a snake .
• Large Tegu lizards of South America have converged in form and ecology with Varanidae|monitor lizards, which are not present in the Americas.
• legless lizards-Pygopodidae are snake-like lizards that are much like true snakes.
• Mosasaurs of the Mesozoic era are like whales but are closely related to living monitor lizards and the Komodo Dragon.
• Anolis lizards are one of the best examples of both adaptive radiation and convergent evolution.
• Tuataras resemble lizards but in fact are in an order of their own, the Rhynchocephalia. The Tuatara has the sockets behind the eyes and has jagged extensions of the jaws instead of teeth.

Avian

• Ostriches are large ratites specialised to cursoriality, having lost the first and second toes. Eogruids were crane relatives that also specialised for cursoriality in the same way, showing a reduction in the second toe's trochea, culminating in its disappearance in more derived taxa.
• The Little Auk of the north Atlantic Ocean|Atlantic (Charadriiformes) and the diving-petrels of the southern oceans (Procellariiformes) are remarkably similar in appearance and habits.
• The Eurasian magpie is a corvid, the Australian magpie is not.
• Penguins in the Southern Hemisphere evolved similarly to flightless wing-propelled diving auks in the Hemisphere Northern Hemisphere: the Atlantic Great Auk and the Pacific Mancallinae|mancallines.
• Vultures are a result of convergent evolution: both Old World vultures and New World vultures eat carrion, but Old World vultures are in the eagle and hawk family (Accipitridae) and use mainly eyesight for discovering food; the New World vultures are of obscure ancestry, and some use the sense of smell as well as sight in hunting. Birds of both families are very big, search for food by soaring, circle over sighted carrion, flock in trees, and have unfeathered heads and necks.

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  Nubian Vulture, an Old World vulture

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  Turkey Vulture, a New World vulture

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  Hummingbird, a New World bird, with a sunbird, an Old World bird

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  Comparison of an ostrich and the eogruid Ergilornis (to scale), combined with the closest living relatives, a tinamou and a trumpeter respectively (not to scale).

• Hummingbirds resemble sunbirds. The former live in the Americas and belong to an order or superorder including the swifts, while the latter live in Africa and Asia and are a family in the order Passeriformes.
• 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 the above mentioned birds.
• Flightless bird|Flightlessness has evolved in many different birds independently. However, taking this to a greater extreme, the terror birds, Gastornithiformes and dromornithidae|dromornithids (ironically all extinct) all evolved the similar body shape (flightlessness, long legs, long necks, big heads), yet none of them were closely related. They also share the trait of being giant, flightless birds with vestigial wings, long legs, and long necks with the ratites, although they are not related.
• Certain longclaws (Macronyx) and meadowlarks (Sturnella) have essentially the same striking plumage pattern. The former inhabit Africa and the latter the Americas, and they belong to different lineages of Passerida. While they are ecologically quite similar, no satisfying explanation exists for the convergent plumage; it is best explained by sheer chance.
• Resemblances between swifts and swallows is due to convergent evolution.
• Downy Woodpecker and Hairy Woodpecker look almost the same, as do some Chrysocolaptes and Dinopium flamebacks, the Smoky-brown Woodpecker and some Veniliornis species, and other Veniliornis species and certain "Picoides" and piculus. In neither case are the similar species particularly close relatives.
• Many birds of Australia, like wrens and Petroicidae|robins, look like northern hemisphere birds but are not related.
• Oilbird like microbats and toothed whales developed sonar-like animal echolocation|echolocation systems used for locating prey.
• The brain structure, forebrain, of hummingbirds, songbirds, and parrots responsible for vocal learning (not by instinct) is very similar. These types of birds are not closely related.
• Seriemas and Secretary Birds very closely resemble the ancient dromaeosaurid and troodontid dinosaurs. Both have evolved a retractable sickle-shaped claw on the second toe of each foot, both have feathers, and both are very similar in their overall physical appearance and lifestyle.
• Migrating birds like, Swainson's thrushes can have half the brain sleep, while the other half remains awake. Dolphins, whales, Amazonian manatees and pinnipeds (seals) can do the same. Called Unihemispheric slow-wave sleep.
• Brood parasitism, laying eggs in the nests of birds of other species, happens in types of birds that are not closely related.

Mammals

The skulls of the Thylacine (left) and the Grey Wolf, Canis lupus, are almost identical, although the species are only very distantly related (different infraclasses). The skull shape of the Red Fox, Vulpes vulpes, is even closer to that of the Thylacine.

• Dugongs and whales have very similar-looking tail flukes.
• Several groups of ungulates have independently reduced or lost side digits on their feet, often leaving one or two digits for walking. That name comes from their hooves, which have evolved from claws several times. Among familiar animals, horses have one walking digit and domestic bovines two on each foot. Various other land vertebrates have also reduced or lost digits.
• Similarly, laurasiathere, perissodactyls and afrothere paenungulates have several features in common, to the point of there being no obvious distinction among basal taxa of both groups.
• The pronghorn of North America, while not a true antelope and only distantly related to them, closely resembles the true antelopes of the Old World, both behaviorally and morphologically. It also fills a similar ecological niche and is found in the same biomes.
• Members of the two clades Australosphenida and Theria evolved tribosphenic molars independently.
• The marsupial thylacine (Tasmanian tiger) had many resemblances to the placental canids.
• Several mammal groups have independently evolved prickly protrusions of the skin – echidnas (monotremes), the insectivorous hedgehogs, some tenrecs (a diverse group of shrew-like Madagascan mammals), Old World porcupines (rodents) and New World porcupines (another biological family of rodents). In this case, because the two groups of porcupines are closely related, they would be considered to be examples of parallel evolution; however, neither echidnas, nor hedgehogs, nor tenrecs are close relatives of the Rodentia. In fact, the last common ancestor of all of these groups was a contemporary of the dinosaurs. The eutriconodont Spinolestes that lived in the Early Cretaceous Period represents an even earlier example of a spined mammal, unrelated to any modern mammal group.
• Cat-like sabre-toothed predators evolved in three distinct lineages of mammals – sabre-toothed cats, nimravids ("false" sabre-tooths), and Sparassodonta Thylacosmilus. Gorgonopsids and creodonts also developed long canine teeth, but with no other particular physical similarities.
• A number of mammals have developed powerful fore claws and long, sticky tongues that allow them to open the homes of social insects (e.g., ants and termites) and consume them (myrmecophagy). These include the four species of anteater, more than a dozen armadillos, eight species of pangolin (plus fossil species), the African aardvark, short-beaked echidna|one echidna (an egg-laying monotreme), the enigmatic Fruitafossor, the singular Australian marsupial known as the numbat, the aberrant aardwolf, and possibly also the sloth bear of South Asia, all not related.
• Koalas of Australasia have evolved fingerprints, indistinguishable from those of humans. Apes' fingerprints are very similar to those too.
• The Australian honey possums acquired a long tongue for taking nectar from flowers, a structure similar to that of Lepidoptera|butterflies, some moths, and hummingbirds, and used to accomplish the very same task.
• Marsupial sugar glider and squirrel glider of Australia are like the placental flying squirrel.
• The North American kangaroo rat, Australian hopping mouse, and North African and Asian jerboa have developed convergent adaptations for hot desert environments; these include a small rounded body shape with very large hind legs and long thin tails, a characteristic bipedal hop, and nocturnal, burrowing and seed-eating behaviours. These rodent groups fill similar niches in their respective ecosystems.
• Opossums have evolved an Opposable thumb, a feature which is also commonly found in the non-related primates.
• Marsupial mole has many resemblances to the placental Mole (animal)|mole.
• Marsupial mulgara has many resemblances to the placental mouse.
• Planigale has many resemblances to the deer mouse.
• Marsupial Tasmanian devil has many resemblances to the placental hyena. Similar skull morphology, large canines and crushing carnasial molars.
• Kangaroo has many resemblances to the Patagonian cavy .
• The Marsupial lion had retractable claws, the same way the placental felines (cats) do today.
• Microbats, toothed whales and shrews developed sonar-like animal echolocation|echolocation systems used for orientation, obstacle avoidance and for locating prey. Modern DNA phylogenies of bats have shown that the traditional suborder of echolocating bats (Microchiroptera) is not a true clade, and instead some echolocating bats are more related to non-echolocating Old World fruit bats than to other echolocating species. The implication is that Animal echolocation#Bats|echolocation in at least two lineages of bats, Megachiroptera and Microchiroptera has evolved independently or been lost in Old World fruit bats.
• Animal echolocation|Echolocation in bats and whales also both necessitate high frequency hearing. The protein prestin, which confers high hearing sensitivity in mammals, shows molecular convergence between the two main clades of echolocating bats, and also between bats and dolphins.. Other hearing genes also show convergence between echolocating taxa
• Both the aye-aye lemur and the striped possum have an elongated finger used to get invertebrates from trees. There are no woodpeckers in Madagascar or Australia where the species evolved, so the supply of invertebrates in trees was large.
• Castorocauda and beaver both have webbed feet and a flattened tail, but are not related.
• Prehensile tails came in to a number of unrelated species New World monkeys, kinkajous, porcupines, tree-anteaters, marsupial opossums, and the salamander Bolitoglosssa pangolins, treerats, skinks and chameleons.
• Pig form, large-headed, pig-snouted and hoofs are independent in true pigs in Eurasia and Peccary and Entelodonts.
• Plankton feeding filters, baleen: Whale sharks and baleen whales, like the humpback whale|humpback and blue whale independent have very sophisticated ways of sifting plankton from marine waters.
• There are five species of River dolphin|river/freshwater dolphins, which are not closely related.
• Platypus have what looks like a bird's Beak (hence its scientific name “Ornithorhynchus”), but is a mammal.
• Red blood cells in mammals lack a cell nucleus. In comparison, the red blood cells of other vertebrates have nuclei; the only known exceptions are salamanders of the Batrachoseps genus and fish of the Maurolicus genus.

In humans (biology)

• Andeans and Tibetans living at high elevations independently developed genetic traits that let their hemoglobin bind more oxygen than sea-level humans. Ethiopians took a non-genetic route to high-altitude adaptation.

In ecosystems

• Ecological succession offers many predictably convergent patterns of ecosystem change.

In biogeographies

• Scaling laws, like Copes rule, and biogeographic laws like Foster’s rule and Bergmann’s rule offer many predictable processes of convergence.
• The famous convergence of form seen in the species distributions and types among placental and marsupial mammals, on separate continents
• For examples of biogeographic convergence in intelligence traits, see Conway-Morris (2004) and McGhee (2011).

In humans (culture, technology)

• When we look above individual cultures and do cross-cultural comparisons, we find many examples of developmental features at the leading edge of competitiveness, including inventions like fire, language, stone tools, clubs, sticks, levers, written language, hydraulic empires for our first great cities, wheels, electricity, computers. etc. In each of these cases, a high-order convergence has occurred. These and other specific examples of cultural change look not only evolutionary, but evolutionary developmental (ED). Once they exist, there's no going back, for any culture seeking to stay on the leading edge of physical and informational complexification, and general adaptiveness.
• We also find many examples of constraint laws that operate in social and economic systems, like physicist and EDU scholar Adrian Bejan’s constructal law, and the least action principle (Georgiev Georgi Y. et al. 2015).

Research questions

• How can we better develop a general theory of both optimizing convergence (OC) and less-optimizing convergence (LOC) so we can reliably differentiate between the two?
• How much more common is LOC than OC, in various complex systems?
• When are physical and when are informational forms of optimization more important, in various complex systems?
• Can a general theory of optimizing convergence (OC) be created without the metaphor of evolutionary development (ED)?
• How can we better test and develop theories of evolutionary development (ED) at all scales, from organisms to universes?
• In the theory of evolutionary development (ED), when comparing successively emergent environments (early universe, astrophysics, chemistry, biology, psychology, and societal systems, technological systems), what are the similarities and differences between contingently adaptive ("evolutionary") processes?
• In the theory of evolutionary development (ED), when comparing successively emergent environments , what are the similarities and differences in processes of apparent high optimization ("developmental") processes?

Books

• Lane, Nick (2016) The Vital Question, W.W. Norton.
• Conway-Morris, Simon (2004) Life's Solution: Inevitable Humans in a Lonely Universe, Cambridge U. Press.
• —————— (2015) The Runes of Evolution: How the Universe Became Self-Aware, Templeton Press.
• McGhee, George R (2011) Convergent Evolution: Limited Forms Most Beautiful, MIT Press.
• Parker, Andrew (2003) In the Blink of an Eye, Basic Books.
• Rees, Martin (1999) Just Six Numbers, Basic Books.
• Sagan, Carl (1977) The Dragons of Eden, Ballantine Books.
• Sanderson, M and Hufford, L (eds.) (1996) Homoplasy: The Recurrence of Similarity in Evolution, Academic Press.
• Vermeij, Geerat (1987) Evolution and Escalation, Princeton U. Press.