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Undichna Simplicitas
''Undichna'' is a fish-fin, or fish-swimming fossil trail left as a fossil impression on a substrate, or the opposite impression on an overlying substrate; this type of fossil is an ichnofossil, in this case a specific ichnogenus, ''Undichna''; the term "undichna" is composed of the words: 'und'–'ichna', for "wave-trace". At present, the oldest known ''Undichna'' were made by cephalaspids, that only had presumptive motion scenarios, due to the physiological form of the cephalaspids as predating the teleosts, (bony fishes). The trails are from the border of England and Wales, from 400 mya, in an ancient riverbed environment. See also *Lateral undulation, a type of undulation for fish, sea animals, and snakes *Trace fossil *Fossil trackway A fossil track or ichnite ( Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of the Paleozoic Era, and the third of twelve periods of the Phanerozoic Eon. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods ( myriapods, arachnids and hexapods) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teleost
Teleostei (; Ancient Greek, Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts (), is, by far, the largest group of ray-finned fishes (class Actinopterygii), with 96% of all neontology, extant species of fish. The Teleostei, which is variously considered a Division (zoology), division or an infraclass in different taxonomic systems, include over 26,000 species that are arranged in about 40 order (biology), orders and 448 family (biology), families. Teleosts range from giant oarfish measuring or more, and ocean sunfish weighing over , to the minute male anglerfish ''Photocorynus spiniceps'', just long. Including not only torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and seahorses. The difference between teleosts and other bony fish lies mainly in their jaw bones; teleosts have a movable premaxilla and corresponding modifications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Trackway
A fossil track or ichnite ( Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the years, many ichnites have been found, around the world, giving important clues about the behaviour (and foot structure and stride) of the animals that made them. For instance, multiple ichnites of a single species, close together, suggest 'herd' or 'pack' behaviour of that species. Combinations of footprints of different species provide clues about the interactions of those species. Even a set of footprints of a single animal gives important clues, as to whether it was bipedal or quadrupedal. In this way, it has been suggested that some pterosaurs, when on the ground, used their forelimbs in an unexpected quadrupedal action. Special conditions are required, in order to preserve a footprint made in soft ground (such as an alluvial plain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trace Fossil
A trace fossil, also called an ichnofossil (; ), 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 term in its broadest sense also includes the remains of other organic material produced by an organism; for example coprolites (fossilized droppings) or chemical markers (sedimentological structures produced by biological means; for example, the formation of stromatolites). However, most sedimentary struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snake
Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have skulls with several more joints than their lizard ancestors and relatives, enabling them to swallow prey much larger than their heads ( cranial kinesis). To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most only have one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. Lizards have independently evolved elongate bodies without limbs or with greatly reduced limbs at least twenty-five times via convergent evolution, leading to many lineages of legless lizards. These resemble snakes, but several common groups of legless lizards have eyelids and external ears, which snakes lack, althoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Undulation
Undulatory locomotion is the type of motion characterized by wave-like movement patterns that act to propel an animal forward. Examples of this type of gait include crawling in snakes, or swimming in the lamprey. Although this is typically the type of gait utilized by limbless animals, some creatures with limbs, such as the salamander, forgo use of their legs in certain environments and exhibit undulatory locomotion. In robotics this movement strategy is studied in order to create novel robotic devices capable of traversing a variety of environments. Environmental interactions In limbless locomotion, forward locomotion is generated by propagating flexural waves along the length of the animal's body. Forces generated between the animal and surrounding environment lead to a generation of alternating sideways forces that act to move the animal forward. These forces generate thrust and drag. Hydrodynamics Simulation predicts that thrust and drag are dominated by viscous forces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mya (unit)
Mya or MYA may refer to: Brands and product names * Mya (TV channel), an Italian Television channel * Mya (program), an intelligent personal assistant created by Motorola * Midwest Young Artists, a comprehensive youth music program Codes * Burmese language (ISO 639-3: ) * Moruya Airport (IATA code: MYA), New South Wales, Australia * The IOC, license plate, and UNDP country code for Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ... People * Mya (given name) * Mya (singer) (Mya Marie Harrison, born 1979), American R&B singer-songwriter and actress * Bo Mya (1927–2006), Myanmar rebel leader and chief commander of the Karen National Union Other uses * ''Mýa'' (album), a 1998 album by Mýa * ''Mya'' (bivalve), a genus of soft-shell clams * Million years a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wales
Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic Sea to the south-west. , it had a population of 3.2 million. It has a total area of and over of Coastline of Wales, coastline. It is largely mountainous with its higher peaks in the north and central areas, including Snowdon (), its highest summit. The country lies within the Temperate climate, north temperate zone and has a changeable, Oceanic climate, maritime climate. Its capital and largest city is Cardiff. A distinct Culture of Wales, Welsh culture emerged among the Celtic Britons after the End of Roman rule in Britain, Roman withdrawal from Britain in the 5th century, and Wales was briefly united under Gruffudd ap Llywelyn in 1055. After over 200 years of war, the Conquest of Wales by Edward I, conquest of Wales by King Edward I o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
England
England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It shares Anglo-Scottish border, a land border with Scotland to the north and England–Wales border, another land border with Wales to the west, and is otherwise surrounded by the North Sea to the east, the English Channel to the south, the Celtic Sea to the south-west, and the Irish Sea to the west. Continental Europe lies to the south-east, and Ireland to the west. At the 2021 United Kingdom census, 2021 census, the population was 56,490,048. London is both List of urban areas in the United Kingdom, the largest city and the Capital city, capital. The area now called England was first inhabited by modern humans during the Upper Paleolithic. It takes its name from the Angles (tribe), Angles, a Germanic peoples, Germanic tribe who settled du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physiology
Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organ (biology), organs, cell (biology), cells, and biomolecules carry out chemistry, chemical and physics, physical functions in a living system. According to the classes of organisms, the field can be divided into clinical physiology, medical physiology, Zoology#Physiology, animal physiology, plant physiology, cell physiology, and comparative physiology. Central to physiological functioning are biophysics, biophysical and biochemical processes, homeostasis, homeostatic control mechanisms, and cell signaling, communication between cells. ''Physiological state'' is the condition of normal function. In contrast, ''pathology, pathological state'' refers to abnormality (behavior), abnormal conditions, including human diseases. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undichna Britannica
''Undichna britannica'' is a fish-fin, or fish-swimming fossil trackway left as a fossil impression on a substrate; this type of fossil is an ichnofossil, and in this case an ichnospecies. The ''U. britannica'' fish-fin tracks, or trackways are often associated with current or wave ripple marks, probably shallow water, near-shoreline. Other deep water varieties may be less common, or associated with narrowed current flow between obstructions. The sinusoidal high points of the ripple marks may lend itself to the formation of the trackways. See also *Trace fossil *Fossil trackway A fossil track or ichnite ( Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the ye ... External linksPhoto-(non-ripple mark associated) [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalaspid
Cephalaspidida is an extinct order of jawless fish in the subclass Cornuata. See also * ''Undichna ''Undichna'' is a fish-fin, or fish-swimming fossil trail left as a fossil impression on a substrate, or the opposite impression on an overlying substrate; this type of fossil is an ichnofossil, in this case a specific ichnogenus, ''Undichna''; ...'', a fish-fin, or fish-swimming fossil trail left as a fossil impression on a substrate, or the opposite impression on an overlying substrate * Anatol Heintz (1898–1975), a Norwegian palaeontologist who published in 1939 ''Cephalaspida from Downtonian of Norway'', about cephalaspida excavated at Ringerike. References * J. A. Moy-Thomas and R. S. Mile. 1971. ''Palaeozoic Fishes'' External links * Cephalaspidida at fossilworks.org(retrieved 16 April 2016) Osteostraci Prehistoric jawless fish orders {{Paleo-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
