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Typically mammalian skin consists of collagen fibers arranged in a felt-work pattern, with no preferential fiber orientation. [12] However, the structures of skin in bats, birds, and gliding lizards are very different from those of typical mammalian skin. The structural arrangement of the fibers within bat wing skin enables the bat to act like ...
All mammals have some hair on their skin, even marine mammals like whales, dolphins, and porpoises that appear to be hairless. The skin interfaces with the environment and is the first line of defense from external factors. For example, the skin plays a key role in protecting the body against pathogens [3] and excessive water loss. [4]
Among mammals, there is a marked tendency in equatorial and tropical regions to have a darker skin color than poleward relatives. In this case, the underlying cause is probably the need to better protect against the more intense solar UV radiation at lower latitudes.
Allen's rule - Hare and its ears on the Earth [1]. Allen's rule is an ecogeographical rule formulated by Joel Asaph Allen in 1877, [2] [3] broadly stating that animals adapted to cold climates have shorter and thicker limbs and bodily appendages than animals adapted to warm climates.
Adaptation is an observable fact of life accepted by philosophers and natural historians from ancient times, independently of their views on evolution, but their explanations differed. Empedocles did not believe that adaptation required a final cause (a purpose), but thought that it "came about naturally, since such things survived."
Unlike Benton, for example, Jacques Gauthier and colleagues forwarded a definition of Amniota in 1988 as "the most recent common ancestor of extant mammals and reptiles, and all its descendants". [26] As Gauthier makes use of a crown group definition, Amniota has a slightly different content than the biological amniotes as defined by an ...
Cutaneous respiration, or cutaneous gas exchange (sometimes called skin breathing), [1] is a form of respiration in which gas exchange occurs across the skin or outer integument of an organism rather than gills or lungs. Cutaneous respiration may be the sole method of gas exchange, or may accompany other forms, such as ventilation.
Mammalian xerocoles sweat much less than their non-desert counterparts. For example, the camel can survive ambient temperatures as high as 49 °C (120 °F) without sweating, [6] and the kangaroo rat lacks sweat glands entirely. [7] Both birds and mammals in the desert have oils on the surface of their skin to "waterproof" it and inhibit ...