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The development of the kidney proceeds through a series of successive phases, each marked by the development of a more advanced kidney: the archinephros, pronephros, mesonephros, and metanephros. [1] The pronephros is the most immature form of kidney, while the metanephros is most developed. The metanephros persists as the definitive adult kidney.
The unipapillary kidney with a single renal pyramid is the simplest type of kidney in mammals, from which the more structurally complex kidneys are believed to have evolved. [ 17 ] [ 6 ] [ 18 ] Differences in kidney structure are the result of adaptations during evolution to variations in body mass and habitats (in particular, aridity ) between ...
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs [1] that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. [ 2 ] [ 3 ] They are located on the left and right in the retroperitoneal space , and in adult humans are about 12 centimetres ( 4 + 1 ⁄ 2 inches) in ...
Scientists have grown kidneys containing mostly human cells inside pig embryos, an important step toward growing kidneys and potentially other human organs.
The granular poison frog (Oophaga granulifera) is typical of a number of tree frogs in the poison dart frog family Dendrobatidae. Its eggs are laid on the forest floor and when they hatch, the tadpoles are carried one by one on the back of an adult to a suitable water-filled crevice such as the axil of a leaf or the rosette of a bromeliad .
Frogs are valued as food by humans and also have many cultural roles in literature, symbolism and religion. They are also seen as environmental bellwethers, with declines in frog populations often viewed as early warning signs of environmental damage. Frog populations have declined significantly since the 1950s.
Tyrone B. Hayes (born July 29, 1967) is an American biologist and professor of integrative biology at the University of California, Berkeley.He is known for his research in frogs, concluding that the herbicide atrazine is an endocrine disruptor that demasculinizes male frogs, causing them to display female characteristics.
A Cuban tree frog explored in Lake Worth, Florida in 2010. According to the University of Florida, the frogs are an invasive species.