These two succulent plant Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climate or soil conditions. Succulent plants store water in their leaves, stems and/or roots. Geophytes survive unfavourable periods by dying back to underground storage organs . They can be regarded as succulents. Some plants are succulent genera, Euphorbia Euphorbia is a genus of plants belonging to the family Euphorbiaceae. Consisting of about 2160 species, Euphorbia is one of the most diverse genera in the plant kingdom, maybe exceeded only by Senecio . Members of the family and genus are sometimes referred to as Spurges. Euphorbia antiquorum and Euphorbia serrata are the type species for the and Astrophytum, are only distantly related, but have independently converged on a very similar body form.
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.
The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, birds Birds are winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 3 m (10 ft) Ostrich and bats Bats are flying mammals in the order Chiroptera . The forelimbs of bats are webbed and developed as wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums and colugos, glide rather than fly, and only for short distances. Bats do not flap do, and are capable of powered flight. The wings are similar in construction, due to the physical constraints imposed upon wing shape. Similarity can also be explained by shared ancestry, as evolution can only work with what is already there—thus wings were modified from limbs, as evidenced by their bone structure.[1]
Traits arising through convergent evolution are termed analogous Two structures in biology are said to be analogous if they perform the same or similar function by a similar mechanism but evolved separately. Similar structures may have evolved through different pathways, a process known as convergent evolution, or may be homologous structures, in contrast to homologous In evolutionary biology, homology refers to any similarity between characteristics of organisms that is due to their shared ancestry. The word homologous derives from the ancient Greek ομολογειν, 'to agree'. There are examples in different branches of biology. Anatomical structures that perform the same function in different biological structures, which have a common origin. Bat and pterodactyl Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period (220 to 65.5 million years ago). Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the legs wings are an example of analogous structures, while the bat wing is homologous to human Humans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. They are the only surviving members of the genus Homo. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving. This mental capability, combined with an erect body carriage that frees the and other mammal Mammals are a class of vertebrate, air-breathing animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair and/or fur, three middle ear bones used in hearing, and a neocortex region in the brain forearms, sharing an ancestral state despite serving different functions. Similarity in species of different ancestry which is the result of convergent evolution, is called homoplasy. The opposite of convergent evolution is divergent evolution Divergent evolution is the accumulation of differences between groups which can lead to the formation of new species, usually a result of diffusion of the same species adapting to different environments, leading to natural selection defining the success of specific mutations. Primarily difussion is the basis of molecular division can be seen in, whereby related species evolve different traits. On a molecular level, this can happen due to random mutation unrelated to adaptive changes; see long branch attraction Long branch attraction is a phenomenon in phylogenetic analyses (most commonly those employing maximum parsimony) when rapidly evolving lineages are inferred to be closely related, regardless of their true evolutionary relationships. For example, in DNA sequence-based analyses, the problem arises when sequences from two (or more) lineages evolve. Convergent evolution is similar to, but distinguishable from, the phenomena of evolutionary relay and parallel evolution Parallel evolution is the development of a similar trait in different not closely related species , but descending from the same ancestor. Evolutionary relay describes how independent species acquire similar characteristics through their evolution in similar ecosystems, at different times: for example the dorsal fins A dorsal fin is a polyphyletic fin located on the backs of some fish, whales, dolphins, and porpoises, as well as the ichthyosaurs. Depending on the species, an animal can have up to three of them. The bones that support the dorsal fin are called Pterygiophore of extinct ichthyosaurs Ichthyosaurs were giant marine reptiles that resembled fish and dolphins. Ichthyosaurs thrived during much of the Mesozoic era; based on fossil evidence, they first appeared approximately 245 million years ago (mya) and disappeared about 90 million years ago, about 25 million years before the dinosaurs became extinct. During the middle Triassic and sharks Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago, before the time of the dinosaurs. Parallel evolution occurs when two independent species evolve together at the same time in the same ecospace and acquire similar characteristics—for instance extinct browsing-horses The evolution of the horse involves the gradual development of the modern horse from the fox-sized, forest-dwelling Hyracotherium. Paleozoologists have been able to piece together a more complete picture of the modern horse's evolutionary lineage than that of any other animal and paleotheres.
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With their Convergence Center of Excellence (CCE) already operating in full swing, located in Noblesville, Ind., Stanley Convergent Security Solutions (CSS) ...
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Sun, 13 Sep 2009 21:54:15 GM
He commented that the Spice Girl and I were products of . convergent evolution. two people from completely unrelated backgrounds who had serendipitously developed similar tastes and interests. This was brought home when we passed a ...
