Convergent evolution - the evolution of similar traits in unrelated lineages - is rife in nature, as illustrated by the examples below.
In animals
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.1
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.
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, 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, very similar to those of humans.
The Australian honey possums acquired a long tongue for taking nectar from flowers, a structure similar to that of butterflies, some moths, and hummingbirds, and used to accomplish the very same task.
The North American kangaroo rat, Australian hopping mice, 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.
Both the aye-aye lemur and the striped possum have an elongated finger used to get bugs from trees. There are no woodpeckers in Madagascar or Australia where the species evolved, so the supply of bugs in trees was large.
Castorocauda and beaver both have webbed feet and a flattened tail, but are not related.
Ornithischian (bird-hipped) dinosaurs had a pelvis shape similar to that of birds, or avian dinosaurs, which evolved from saurischian (lizard-hipped) dinosaurs.
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.
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.
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 whaleAmbulocetus. 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 particuler species in both groups.
Cichlids of South America and the "sunfish" of North America are strikingly similar in morphology, ecology and behavior. The Peacock Bass and Largemouth Bass are excellent examples.
Two lineages of frogs among the Neobatrachia are due to convergent evolution.
The Neotropicalpoison 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).
Arthropods
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.
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
The brachiopods (non-molluscs) and bivalve molluscs 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.
Clamlike shells – Phylum Mollusca like clams and oysters and the Phylum Brachiopoda like brachiopods and lampshells, independent have invented paired shells for protection. The anatomy of their soft body parts is so dissimilar, however, that they are regarded as separate, independent phyla. Biologists think that clams are more closely related to earthworms than they are to brachiopods.
Jet propulsion of squids and scallops, although both mollusks have independent very different ways of squeezing water through their bodies to power their movement through a fluid. Dragonfly larvae in the aquatic stage, use an anal jet to propel them. Jellyfish have had jet propulsion a long time.
Prickles, thorns and spines are all modified plant tissues that have evolved to prevent or limit herbivory, these structures have evolved independently a number of times.
Hallucinogenic toxins: Plants as diverse as the peyotyl cactus and the ayahuascavine produce the same form of chemical toxin to deter predators.
The aerial rootlets found in ivy (Hedera) are similar to those of the 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 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.
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).
The biosynthesis of plant hormones such as gibberellin and abscisic acid by different biochemical pathways in plants and fungi.23
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.