The Dugong, often referred to as the sea cow, is actually more closely related to elephants than to the bovine namesake. Throughout much of their range, the Dugong has...
FluorineLast Updated on 2014-09-13 19:14:38Fluorine is a highly reactive chemical element with atomic symbol F. Having the atomic number nine, fluorine is the lightest halogen. Fluorine is a yellow-green gas which does not occur as a free, unreacted element in the natural environment. Under conditions of standard temperature and pressure, elemental fluorine forms a diatomic molecule with chemical formula F2. Chemically, fluorine is one of the strongest known oxidizing agents, and even more reactive and hazardous than chlorine. Its very high electron affinity causes fluorine to react directly with almost all other elements except for several of the Noble gases.
Previous Element: Oxygen
Next Element: Neon
Phase at Room Temp.
Density... More »
Sundarbans National Park, IndiaLast Updated on 2014-09-09 11:56:45
Sundarbans National Park (21°31'-21°53'N, 88°37'-89°09'E) is a World Heritage Site that lies southeast of Calcutta in the 24-Paraganas District of West Bengal and forms part of the Gangetic Delta, which borders on the Bay of Bengal. Consists of Matla, Goashaba, Chhotahardi, Mayadwip, Chamta, Gona and Baghmara forest blocks, which are bounded by the Matla/Bidya and Haribhanga/Raimangal rivers to the east and west, respectively. The northern boundary is buffered by Netidhopani and Chandkhali forest blocks.
Established as a national park on 4 May 1984 (Notification No. 2867-For). Previously created a wildlife sanctuary in 1977, having been designated as the core area of Sundarbans Tiger Reserve in December 1973. All forest in 24-Paraganas District was first notified as protected forest on 7 December 1878. Much of this was subsequently leased out by... More »
ReptileLast Updated on 2014-09-09 11:10:24
Reptiles do not form a distinct evolutionary group as birds and mammals do. Rather, the Class Reptilia consists of four orders which are very different from each other. For example, lizards are more closely related to birds than to turtles!
As a result, reptiles are as easily defined by what they aren't as by what they are.
As opposed to mammals and birds, reptiles have neither fur nor feathers, but scales. Reptiles can not be confused with amphibians because reptiles have dry, water-proof skin and eggs, as well as internal fertilization and more advanced circulatory, respiratory, excretory, and nervous systems.
Reptiles evolved from labyrinthodont amphibians 300 million years ago. The success of this terrestrial vertebrate group is due in large part to the evolution of shelled, large-yolked eggs in which the embryo has an independent water supply. This advance, as... More »
AmphibianLast Updated on 2014-09-09 10:57:59
The term amphibian comes from the Greek amphibios meaning "both lives". This is an apt description because most adult amphibians are better adapted to life on land than in water, while their larval phases are entirely aquatic.
For much of their lives, which may last a couple of months or several years depending on the species, larval amphibians bear little resemblance to their adult forms. Then something miraculous happens. In a matter of weeks or even days, the once fish-like larvae metamorphose into terrestrial, air-breathing quadrupeds!
There are three extant orders in the Class Amphibia: Anura (frogs and toads), Caudata (salamanders), and Apoda (caecilians). The order Anura has the most extant species, with 4000 members worldwide. Of Caudata, 390 salamander species exist worldwide. The third amphibian group, the caecilians, is smaller still with a total of only 162... More »
MutualismLast Updated on 2014-09-09 10:48:53
Mutualisms are ecological interactions between two species in which both benefit. Many mutualisms involve species living closely together (symbiosis); a species may be so dependent that it cannot live without its mutualistic partner (obligate mutualism). In other cases, a species can interact mutualistically with more than one partner (diffuse mutualism) or even live without its partner(s) under certain conditions (facultative mutualism). Although all species involved in a mutualistic relationship contribute to the partnership, we still expect each species to be "selfish" and to evolve traits that provide the maximum possible fitness benefit while minimizing cost.
1. Trophic mutualisms are interactions in which both species receive a benefit of resources. Organisms require both nutrients and energy to survive. In many trophic mutualisms, a plant provides energy... More »
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