|
Veiled Chameleon
The veiled chameleon (''Chamaeleo calyptratus'') is a species of chameleon (family Chamaeleonidae) native to the Arabian Peninsula in Yemen and Saudi Arabia. Other common names include cone-head chameleon, Yemen chameleon, and Yemeni chameleon. They are born pastel green and without their distinctive casques on their head. As they mature, their casque develops along with more vibrant coloring, as well as a dramatic gular fold that will protrude from their throat and chin. They are known for their variable color changes due to a variety of factors, including to show aggression, social status, reproduction, and stress. Female lifespan is around five years while male lifespan is around eight, and they breed a few times a year. Etymology The term 'veiled chameleon' refers to the species ''Chamaeleo calyptratus''. 'Veiled' describes their distinctive casque on the head, resembling a veil. This term highlights the species' unique feature. The generic term 'chameleon' is derived f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
André Marie Constant Duméril
André Marie Constant Duméril (1 January 1774 – 14 August 1860) was a French zoologist. He was professor of anatomy at the National Museum of Natural History (France), Muséum national d'histoire naturelle from 1801 to 1812, when he became professor of herpetology and ichthyology. His son Auguste Duméril was also a zoologist, and the author citation (zoology), author citation Duméril is used for both André and his son. Life André Marie Constant Duméril was born on 1 January 1774 in Amiens and died on 14 August 1860 in Paris. He became a doctor at a young age, obtaining, at 19 years, the ''prévot'' of anatomy at the medical school of Rouen. In 1800, he left for Paris and collaborated in the drafting of the comparative anatomy lessons of Georges Cuvier. He replaced Cuvier at the Central School of the Panthéon, Paris, Panthéon and had, as his colleague, Alexandre Brongniart. In 1801, he gave courses to the medical school of Paris. Under the Bourbon Restoration in Fran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casque (anatomy)
A casque is an anatomical feature found in some species of birds, reptiles, and amphibians. In birds, it is an enlargement of the bones of the upper mandible or the skull, either on the front of the face, the top of the head, or both. The casque has been hypothesized to serve as a visual cue to a bird's sex, state of maturity, or social status; as reinforcement to the beak's structure; or as a resonance chamber, enhancing calls. In addition, they may be used in combat with other members of the same species, in the gathering of food, or in thermoregulation. Birds Structure Casques are found in a number of species, including most hornbills, all cassowaries, the maleo, the horned guan, the helmeted guineafowl and several species of curassow. In most of these species, the casque is a bony extension of the or skull that is covered with a cornified layer of skin. However, in cassowaries, a foamy, elastic layer of collagen sits between the bone and the skin. Hornbill casques grow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrulation
Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells), or in mammals, the blastocyst, is reorganized into a two-layered or three-layered embryo known as the gastrula. Before gastrulation, the embryo is a continuous epithelial sheet of cells; by the end of gastrulation, the embryo has begun differentiation to establish distinct cell lineages, set up the basic axes of the body (e.g. dorsal–ventral, anterior–posterior), and internalized one or more cell types, including the prospective gut. Gastrula layers In triploblastic organisms, the gastrula is trilaminar (three-layered). These three germ layers are the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer).Mundlos 2009p. 422/ref>McGeady, 2004: p. 34 In diploblastic organisms, such as Cnidaria and Ctenophora, the gastrula has only ectoderm and endoderm. The two layers are also sometimes referred to as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryonic Development
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm, sperm cell (spermatozoon). Once fertilized, the ovum becomes a single diploid cell known as a zygote. The zygote undergoes mitosis, mitotic cell division, divisions with no significant growth (a process known as cleavage (embryo), cleavage) and cellular differentiation, leading to development of a multicellular embryo after passing through an organizational checkpoint during mid-embryogenesis. In mammals, the term refers chiefly to the early stages of prenatal development, whereas the terms fetus and fetal development describe later stages. The main stages of animal embryonic development are as follows: * The zygote undergoes a series of cell divisions (called cleavage) to form a structure called a morula. * The morula develops into a structure called a bla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diapause
In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It is a physiological state with very specific initiating and inhibiting conditions. The mechanism is a means of surviving predictable, unfavorable environmental conditions, such as temperature extremes, drought, or reduced food availability. Diapause is observed in all the life stages of arthropods, especially insects. Activity levels of diapausing stages can vary considerably among species. Diapause may occur in a completely immobile stage, such as the pupae and eggs, or it may occur in very active stages that undergo extensive migrations, such as the adult monarch butterfly, ''Danaus plexippus''. In cases where the insect remains active, feeding is reduced and reproductive development is slowed or halted. Embryonic diapause, a somewhat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clutch (eggs)
A clutch of eggs is the group of eggs produced by birds, amphibians, or reptiles, often at a single time, particularly those laid in a nest. In birds, destruction of a clutch by predators (or removal by humans, for example the California condor breeding program) results in ''double-clutching''. The technique is used to double the production of a species' eggs, in the California condor case, specifically to increase population size. Size Clutch size differs greatly between species, sometimes even within the same genus. It may also differ within the same species due to many factors including habitat, health, nutrition, predation pressures, and time of year. Clutch size variation can also reflect variation in optimal reproduction effort. In birds, clutch size can vary within a species due to various features (age and health of laying female, ability of male to supply food, and abundance of prey), while some species are determinant layers, laying a species-specific number of egg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insectivore
file:Common brown robberfly with prey.jpg, A Asilidae, robber fly eating a hoverfly An insectivore is a carnivore, carnivorous animal or plant which eats insects. An alternative term is entomophage, which can also refer to the Entomophagy in humans, human practice of eating insects. The first vertebrate insectivores were amphibians. When they evolved 400 million years ago, the first amphibians were piscivores, with numerous sharp conical teeth, much like a modern crocodile. The same tooth arrangement is however also suited for eating animals with exoskeletons, thus the ability to eat insects can stem from piscivory. At one time, insectivorous mammals were scientific classification, scientifically classified in an order (biology), order called Insectivora. This order is now abandoned, as not all insectivorous mammals are closely related. Most of the Insectivora taxa have been reclassified; those that have not yet been reclassified and found to be truly related to each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valley
A valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a very long period. Some valleys are formed through erosion by glacial ice. These glaciers may remain present in valleys in high mountains or polar areas. At lower latitudes and altitudes, these glacially formed valleys may have been created or enlarged during ice ages but now are ice-free and occupied by streams or rivers. In desert areas, valleys may be entirely dry or carry a watercourse only rarely. In areas of limestone bedrock, dry valleys may also result from drainage now taking place underground rather than at the surface. Rift valleys arise principally from earth movements, rather than erosion. Many different types of valleys are described by geographers, using terms that may be global in use or else applied only locally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountain
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher than a hill, typically rising at least above the surrounding land. A few mountains are inselberg, isolated summits, but most occur in mountain ranges. mountain formation, Mountains are formed through tectonic plate, tectonic forces, erosion, or volcanism, which act on time scales of up to tens of millions of years. Once mountain building ceases, mountains are slowly leveled through the action of weathering, through Slump (geology), slumping and other forms of mass wasting, as well as through erosion by rivers and glaciers. High elevations on mountains produce Alpine climate, colder climates than at sea level at similar latitude. These colder climates strongly affect the Montane ecosystems, ecosystems of mountains: different elevations hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plateau
In geology and physical geography, a plateau (; ; : plateaus or plateaux), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides have deep hills or escarpments. Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Plateaus are classified according to their surrounding environment as intermontane, piedmont, or continental. A few plateaus may have a small flat top while others have wider ones. Formation Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, plate tectonics movements, and erosion by water and glaciers. Volcanic Volcanic plateaus are produced by volcanic activity. They may be formed by upwelling of volcanic magma or extrusion of lava. The underlining mechanism in forming p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arboreal Locomotion
Arboreal locomotion is the animal locomotion, locomotion of animals in trees. In habitats in which trees are present, animals have evolution, evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The habitats pose numerous mechanical challenges to animals moving through them and lead to a variety of anatomical, behavioral and ecological consequences as well as variations throughout different species.Matt Cartmill, Cartmill, M. (1985). "Climbing". pp. 73–88 ''In'': Hildebrand, Milton; Bramble, Dennis M.; species:Karel Frederik Liem, Liem, Karel F.; David B. Wake, Wake, David B. (editors) (1985). ''Functional Vertebrate Morphology''. Cambridge, Massachusetts: Harvard University Press, Belknap Press. 544 pp. . Furthermore, many of these same principles may be applied to climbing without trees, such as on rock piles or mountains. Some animals are exclusively arboreal in habitat, such as tree snails. Biomechanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Peters
Wilhelm Karl Hartwich (or Hartwig) Peters (22 April 1815 – 20 April 1883) was a German natural history, naturalist and explorer. He was assistant to the anatomist Johannes Peter Müller and later became curator of the Natural History Museum, Berlin, Berlin Zoological Museum. Encouraged by Müller and the explorer Alexander von Humboldt, Peters travelled to Mozambique via Angola in September 1842, exploring the coastal region and the Zambesi River. He returned to Berlin with an enormous collection of natural history specimens, which he then described in ''Naturwissenschaftliche Reise nach Mossambique... in den Jahren 1842 bis 1848 ausgeführt'' (1852–1882). The work was comprehensive in its coverage, dealing with mammals, birds, reptiles, amphibians, river fish, insects and botany. He replaced Martin Lichtenstein as curator of the museum in 1858, and in the same year he was elected a foreign member of the Royal Swedish Academy of Sciences. In a few years, he greatly increased ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
