Triassic in the context of Neopterygii

Bipedalism is a form of terrestrial locomotion where an animal moves by means of its two rear (or lower) limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped /ˈbaɪpɛd/, meaning 'two feet' (from Latin bis 'double' and pes 'foot'). Types of bipedal movement include walking or running (a bipedal gait) 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 such as australopithecines, including humans, as well as many other extinct groups evolving the trait independently.

Skanderbeg Mountains (Albanian: Vargmalet e Skënderbeut), also known as Vargmalet Perëndimore, are a prominent mountain range situated in the northwestern section of the Central Mountain Region of Albania. The range stretches approximately 100 km (62 mi), making it the longest in the country. It extends from the Gjadër river valley in the northwest to the Shkumbin river valley in the southeast; and from the trough of Mat in the east, to the plains between Lezhë, Tirana and Lower Shkodër in the west.

The eastern side of the range is composed primarily of limestone from the Triassic-Jurassic periods, separated into distinct blocks, while the western side is composed of limestone from the Ordovician and the Cretaceous-Paleogene periods, forming belts amid the Paleogene flysch. Ultrabasic rocks are also present, and the older flysch appears in the form of surface bands on the eastern side of the range.

The Jurassic (/dʒʊˈræsɪk/ juurr-ASS-ik) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 Ma (million years ago) to the beginning of the Cretaceous Period, 143.1 Ma. The Jurassic constitutes the second and middle period of the Mesozoic Era as well as the eighth period of the Phanerozoic Eon and is named after the Jura Mountains, where limestone strata from the period were first identified.

The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province (CAMP). The beginning of the Toarcian Age started around 183 Ma and is marked by the Toarcian Oceanic Anoxic Event, a global episode of oceanic anoxia, ocean acidification, and elevated global temperatures associated with extinctions, likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear, definitive boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined.

Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedimentation is any process that causes these particles to settle in place. Geological detritus originates from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus is formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies (marine snow). Sedimentation may also occur when dissolved minerals precipitate from water solution.

The sedimentary rock cover of the continents of the Earth's crust is extensive (73% of the Earth's current land surface), but sedimentary rock is estimated to be only 8% of the volume of the crust. Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks. Sedimentary rocks are deposited in layers as strata, forming a structure called bedding. Sedimentary rocks are often deposited in large structures called sedimentary basins. Sedimentary rocks have also been found on Mars.

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 a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and 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 11,000 living species, are among the most diverse groups of vertebrates. Using fossil evidence, paleontologists have identified over 900 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through most of the 20th century, before birds were recognized as dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some were herbivorous, others carnivorous. Evidence suggests that all dinosaurs were egg-laying, and that nest-building was a trait shared by many dinosaurs, both avian and non-avian.

Termites are a group of detritophagous eusocial cockroaches which consume a variety of decaying plant material, generally in the form of wood, leaf litter, and soil humus. They are distinguished by their moniliform antennae and the soft-bodied, unpigmented worker caste for which they have been commonly termed "white ants"; however, they are not ants but highly derived cockroaches. About 2,997 extant species are currently described, 2,125 of which are members of the family Termitidae.

Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattodea (the cockroaches). Termites were once classified in a separate order from cockroaches, but recent phylogenetic studies indicate that they evolved from cockroaches, as they are deeply nested within the group, and the sister group to wood-eating cockroaches of the genus Cryptocercus. Previous estimates suggested the divergence took place during the Jurassic or Triassic. More recent estimates suggest that they have an origin during the Late Jurassic, with the first fossil records in the Early Cretaceous.

The Permian–Triassic extinction event, colloquially known as the Great Dying, was an extinction event that occurred approximately 251.9 million years ago (mya), at the boundary between the Permian and Triassic geologic periods, and with them the Paleozoic and Mesozoic eras. It is Earth's most severe known extinction event, with the extinction of 57% of biological families, 62% of genera, 81% of marine species, and 70% of terrestrial vertebrate species. It is also the greatest known mass extinction of insects. It is the greatest of the "Big Five" mass extinctions of the Phanerozoic. There is evidence for one to three distinct pulses, or phases, of extinction.

The scientific consensus is that the main cause of the extinction was the flood basalt volcanic eruptions that created the Siberian Traps, which released sulfur dioxide and carbon dioxide, resulting in euxinia (oxygen-starved, sulfurous oceans), elevated global temperatures,and acidified oceans.The level of atmospheric carbon dioxide rose from around 400 ppm to 2,500 ppm with approximately 3,900 to 12,000 gigatonnes of carbon being added to the ocean-atmosphere system during this period.

The formation of the Gulf of Mexico, an oceanic rift basin located between North America and the Yucatan Block, was preceded by the breakup of the Supercontinent Pangaea in the Late-Triassic, weakening the lithosphere. Rifting between the North and South American plates continued in the Early-Jurassic, approximately 160 million years ago, and formation of the Gulf of Mexico, including subsidence due to crustal thinning, was complete by 140 Ma. Stratigraphy of the basin, which can be split into several regions, includes sediments deposited from the Jurassic through the Holocene, currently totaling a thickness between 15 and 20 kilometers.

A craton ( /ˈkreɪtɒn/ KRAYT-on, /ˈkrætɒn/ KRAT-on, or /ˈkreɪtən/ KRAY-tən; from Ancient Greek: κράτος kratos "strength") is an old and stable part of continental lithosphere (the Earth's two topmost layers, the crust and the lithospheric mantle). Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates; the exceptions occur where geologically recent rifting events have separated cratons and created passive margins along their edges. Cratons are composed of ancient crystalline basement rocks covered by younger sedimentary rocks. They have a thick crust and deep lithospheric roots extending several hundred kilometres into Earth's mantle.

Cratons contain the oldest continental crust rocks on Earth. They were formed in the Archaean (4 to 2.5 billion years ago) and the Proterozoic (2.5 billion- 538.8 million year ago) geologic eons. Most were formed in the Archaean.

A trace fossil, also called an ichnofossil (/ˈɪknoʊˌfɒsɪl/; from Ancient Greek ἴχνος (íkhnos) 'trace, track'), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or by mineralization. The study of such trace fossils is ichnology - the work of ichnologists.

Trace fossils may consist of physical impressions made on or in the substrate by an organism. For example, burrows, borings (bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints, feeding marks, and root cavities may all be trace fossils.

The most recent understanding of the evolution of insects is based on studies of the following branches of science: molecular biology, insect morphology, paleontology, insect taxonomy, evolution, embryology, bioinformatics and scientific computing. The study of insect fossils is known as paleoentomology. It is estimated that the class of insects originated on Earth about 480 million years ago, in the Ordovician, at about the same time terrestrial plants appeared. Insects are thought to have evolved from a group of crustaceans. The first insects were landbound, but about 400 million years ago in the Devonian period one lineage of insects evolved flight, the first animals to do so. The oldest insect fossil has been proposed to be Rhyniognatha hirsti, estimated to be 400 million years old, but the insect identity of the fossil has been contested. Global climate conditions changed several times during the history of Earth, and along with it the diversity of insects. The Pterygotes (winged insects) underwent a major radiation in the Carboniferous (358 to 299 million years ago) while the Endopterygota (insects that go through different life stages with metamorphosis) underwent another major radiation in the Permian (299 to 252 million years ago).

Most extant orders of insects developed during the Permian period. Many of the early groups became extinct during the mass extinction at the Permo-Triassic boundary, the largest extinction event in the history of the Earth, around 252 million years ago. The survivors of this event evolved in the Triassic (252 to 201 million years ago) to what are essentially the modern insect orders that persist to this day. Most modern insect families appeared in the Jurassic (201 to 145 million years ago).

In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leaves room for interpretation and is easier to apply to Precambrian times. To separate supercontinents from other groupings, a limit has been proposed in which a continent must include at least about 75% of the continental crust then in existence in order to qualify as a supercontinent.

Moving under the forces of plate tectonics, supercontinents have assembled and dispersed multiple times in the geologic past. According to modern definitions, a supercontinent does not exist today; the closest is the current Afro-Eurasian landmass, which covers approximately 57% of Earth's total land area. The last period in which the continental landmasses were near to one another was 336 to 175 million years ago, forming the supercontinent Pangaea. The positions of continents have been accurately determined back to the early Jurassic, shortly before the breakup of Pangaea. Pangaea's predecessor Gondwana is not considered a supercontinent under the first definition since the landmasses of Baltica, Laurentia and Siberia were separate at the time.

Gryphaea, one of the genera known as devil's toenails, is a genus of extinct oysters, marine bivalve mollusks in the family Gryphaeidae.

These fossils range from the Triassic period to the middle Paleogene period, but are mostly restricted to the Triassic and Jurassic. They are particularly common in many parts of Britain.

The Uralian orogeny refers to the long series of linear deformation and mountain building events that raised the Ural Mountains, starting in the Late Carboniferous and Permian periods of the Palaeozoic Era, c. 323–299 and 299–251 million years ago (Mya) respectively, and ending with the last series of continental collisions in Triassic to early Jurassic times.

The region affected by the orogeny, the Uralian orogenic belt or the Uralides, is usually thought of as the boundary between Europe and Asia. It extends from the Aral Sea to Novaya Zemlya, and it includes in addition to the Ural Mountains, the Pay-Khoy Ridge of northwest Russia and the Mugodzhar Hills of northwest Kazakhstan. Its total length is about 3,500 kilometres (2,200 mi), of which the Ural Mountains are about 2,500 km (1,600 mi).

The Siberian Traps (Russian: Сибирские траппы, romanized: Sibirskiye trappy) are a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. Large volumes of basaltic lava covered a large expanse of Siberia in a flood basalt event. The massive eruptive event that formed the traps is one of the largest known volcanic events in the last 500 million years. The eruptions continued for roughly two million years and spanned the Permian–Triassic boundary, or P–T boundary, which occurred around 251.9 million years ago. The Siberian Traps are believed to be the primary cause of the Permian–Triassic extinction event, the most severe extinction event in the geologic record. Subsequent periods of Siberian Traps activity have been linked to smaller biotic crises, including the Smithian-Spathian, Olenekian-Anisian, Middle-Late Anisian, and Anisian-Ladinian extinction events. Today, the area is covered by about 7 million km (3 million sq mi) of basaltic rock, with a volume of around 4 million km (1 million cu mi).

The Permian (/ˈpɜːrmi.ən/ PUR-mee-ən) is a geologic period and stratigraphic system which spans 47 million years, from the end of the Carboniferous Period 298.9 Ma (million years ago) to the beginning of the Triassic Period 251.902 Ma. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia.

The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids (reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors.