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Bipeds
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' and ''pes'' 'foot'). Types of bipedal movement include walking, running, and hopping. Several groups of modern species are habitual bipeds whose normal method of locomotion is two-legged. In the Triassic period some groups of archosaurs (a group that includes crocodiles and dinosaurs) developed bipedalism; among the dinosaurs, all the early forms and many later groups were habitual or exclusive bipeds; the birds are members of a clade of exclusively bipedal dinosaurs, the theropods. Within mammals, habitual bipedalism has evolved multiple times, with the macropods, kangaroo rats and mice, springhare, hopping mice, pangolins and hominin apes (australopithecines, including humans) as well as various other extinct groups evolving the trait ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together with Saur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrestrial Locomotion
Terrestrial locomotion has evolved as animals adapted from aquatic to terrestrial environments. Locomotion on land raises different problems than that in water, with reduced friction being replaced by the increased effects of gravity. As viewed from evolutionary taxonomy, there are three basic forms of animal locomotion in the terrestrial environment: * legged – moving by using appendages *limbless locomotion – moving without legs, primarily using the body itself as a propulsive structure. *rolling – rotating the body over the substrate Some terrains and terrestrial surfaces permit or demand alternative locomotive styles. A sliding component to locomotion becomes possible on slippery surfaces (such as ice and snow), where location is aided by potential energy, or on loose surfaces (such as sand or scree), where friction is low but purchase (traction) is difficult. Humans, especially, have adapted to sliding over terrestrial snowpack and terrestrial ice by means of ice ska ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosaur
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian dinosaurs, pterosaurs, and extinct relatives of crocodilians. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants. The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives, and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, possessed these features yet originated pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Pangolin
The giant pangolin (''Smutsia gigantea'') is the largest species in the family of pangolins. Members of the species inhabit Africa with a range stretching along the equator from West Africa to Uganda. It subsists almost entirely on ants and termites. The species was first described by Johann Karl Wilhelm Illiger in 1815. Description The giant pangolin is the largest of all pangolin species. While its average mass has not been measured, one specimen was found to weigh 33 kg (72.6 lb). Males are larger than females, with male body lengths about 140 cm (4.6 ft) and females about 125 cm (4.1 ft). Like all pangolins, the species is armored with large, brown to reddish-brown scales formed from keratin. Curiously, it also has eyelashes. The giant pangolin has a long snout, a long, thick tail, and large front claws. The animal has a strong sense of smell and large anal glands. Its secretions may be significant to animal communication. The species walks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrupedalism
Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor'' for "four", and ''pes'', ''pedis'' for "foot"). Quadruped animals are found among both vertebrates and invertebrates. Quadrupeds vs. tetrapods Although the words ‘quadruped’ and ‘tetrapod’ are both derived from terms meaning ‘four-footed’, they have distinct meanings. A tetrapod is any member of the taxonomic unit Tetrapoda (which is defined by descent from a specific four-limbed ancestor), whereas a quadruped actually uses four limbs for locomotion. Not all tetrapods are quadrupeds and not all entities that could be described as ‘quadrupedal’ are tetrapods. This last meaning includes certain artificial objects; almost all quadruped ''organisms'' are tetrapods (with the exception of some raptorial arthropods adapted fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indriidae
The Indriidae (sometimes incorrectly spelled Indridae) are a family of strepsirrhine primates. They are medium- to large-sized lemurs, with only four teeth in the toothcomb instead of the usual six. Indriids, like all lemurs, live exclusively on the island of Madagascar. Classification The 19 living species in the family are divided into three genera. Family Indriidae *Genus ''Indri'' **Indri, ''Indri indri'' *Genus '' Avahi'', woolly lemurs **Bemaraha woolly lemur, ''Avahi cleesei'' **Eastern woolly lemur, ''Avahi laniger'' **Moore's woolly lemur, ''Avahi mooreorum'' **Western woolly lemur, ''Avahi occidentalis'' **Sambirano woolly lemur, ''Avahi unicolor'' **Peyrieras's woolly lemur, ''Avahi peyrierasi'' **Southern woolly lemur, ''Avahi meridionalis'' **Ramanantsoavana's woolly lemur, ''Avahi ramanantsoavani'' **Betsileo woolly lemur, ''Avahi betsileo'' *Genus ''Propithecus'', sifakas **''Propithecus diadema'' group ***Diademed sifaka, ''Propithecus diadema'' ***Silky sifaka, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gibbon
Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforest from eastern Bangladesh to Northeast India to southern China and Indonesia (including the islands of Sumatra, Borneo and Java). Also called the lesser apes, gibbons differ from great apes ( bonobos, chimpanzees, gorillas, orangutans and humans) in being smaller, exhibiting low sexual dimorphism, and not making nests. Like all apes, gibbons are tailless. Unlike most of the great apes, gibbons frequently form long-term pair bonds. Their primary mode of locomotion, brachiation, involves swinging from branch to branch for distances up to , at speeds as fast as . They can also make leaps up to , and walk bipedally with their arms raised for balance. They are the fastest of all tree-dwelling, nonflying mammals. Depending on the species and sex, gibbons' fur coloration varies from dar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia although some lizards are more closely related to these two excluded groups than they are to other lizards. Lizards range in size from chameleons and geckos a few centimeters long to the 3-meter-long Komodo dragon. Most lizards are quadrupedal, running with a strong side-to-side motion. Some lineages (known as "legless lizards"), have secondarily lost their legs, and have long snake-like bodies. Some such as the forest-dwelling ''Draco'' lizards are able to glide. They are often territorial, the males fighting off other males and signalling, often with bright colours, to attract mates and to intimidate rivals. Lizards are mainly carnivorous, often being sit-and-wait predators; many smaller species eat insects, while the Komodo eats mammals a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dipodomyinae
Dipodomyinae is a subfamily of heteromyid rodents, the kangaroo rats and mice. Dipodomyines, as implied by both their common and scientific names, are bipedal; they also jump exceptionally well. Kangaroo rats and mice are native to desert and semidesert ecosystems of western North America from southern Canada to central Mexico. They are generally herbivorous foragers, and dig and live in burrows. Taxonomy Dipodomyinae is the sister group of a Perognathinae-Heteromyinae clade; the two are estimated to have split about 22-24 million years ( Ma) ago. The most recent common ancestor of extant dipodomyines is thought to have lived 15-16 Ma ago, when the two genera split. The most recent common ancestors of extant members of ''Dipodomys'' and ''Microdipodops'' are thought to have lived 10-11 and 7-8 Ma ago, respectively. *Subfamily Dipodomyinae **Genus ''Dipodomys'' — kangaroo rats *** Agile kangaroo rat, ''Dipodomys agilis'' ***California kangaroo rat, ''Dipodomys californicus'' * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australopithecines
Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally ''Australopithecus'' (cladistically including the genera ''Homo'', '' Paranthropus'', and ''Kenyanthropus''), and it typically includes the earlier ''Ardipithecus'', ''Orrorin'', ''Sahelanthropus'', and ''Graecopithecus''. All these closely related species are now sometimes collectively termed australopiths or homininians. They are the extinct, close relatives of humans and, with the extant genus ''Homo'', comprise the human clade. Members of the human clade, i.e. the Hominini after the split from the chimpanzees, are now called Hominina (''see Hominidae; terms "hominids" and hominins''). While none of the groups normally directly assigned to this group survived, the australopiths do not appear to be literally extinct (in the sense of having no living descendants) as the genera ''Kenyanthropus'', ''Paranthropus'' and ''Homo'' probably emerged as sister of a late ''Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hominin
The Hominini form a taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and '' Pan'' (chimpanzees and bonobos) and in standard usage excludes the genus ''Gorilla'' (gorillas). The term was originally introduced by Camille Arambourg (1948). Arambourg combined the categories of ''Hominina'' and ''Simiina'' due to Gray (1825) into his new subtribe. Traditionally, chimpanzees, gorillas and orangutans were grouped together as pongids. Since Gray's classification, evidence has accumulated from genetic phylogeny confirming that humans, chimpanzees, and gorillas are more closely related to each other than to the orangutan. The former pongids were reassigned to the subfamily Hominidae ("great apes"), which already included humans, but the details of this reassignment remain contested; within Hominini, not every source excludes gorillas, and not every source includes chimpanzees. Humans are the only extant species in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
