Note: I decided to provide the information from this site because it gave the history as well as other pertinent information. I watched a documentary covering very interesting information about frogs on PBS. Their mating rituals, the way they change to adjust to their environment from the coloring of their skin to the way their eyes work to enable them to adapt to their environment is very interesting. They have been around for a very long time.
Frogs are tail-less amphibians (class Amphibia, order Anura). With some 3,500 living species, frogs are the most numerous and best known of amphibians. They are found on all continents except Antarctica and are common on many oceanic islands. The terms "frog" and "toad" are derived from early usage in England and northern Europe, where two families of the order Anura occur. One includes slender, long-legged, smooth-skinned animals that live near water: frogs; the other includes short-legged warty animals that live in fields and gardens: toads. When other kinds of animals of this group were discovered elsewhere, such as tree-frogs, fire-bellied toads, and others, it was realized that these various forms actually represented one major group. This group, the anurans, is now commonly referred to as frogs.
Frogs are amphibians, a term derived from two Greek words: amphi meaning double and bios meaning life. The double life of frogs involves living in water and also on land. Because of this amphibious habit, they must have adaptations for each environment. As in other animals that have a separate larval stage and a complex life cycle, frogs have two extremely different morphologies.
Frogs are tail-less amphibians (class Amphibia, order Anura). With some 3,500 living species, frogs are the most numerous and best known of amphibians. They are found on all continents except Antarctica and are common on many oceanic islands. The terms "frog" and "toad" are derived from early usage in England and northern Europe, where two families of the order Anura occur. One includes slender, long-legged, smooth-skinned animals that live near water: frogs; the other includes short-legged warty animals that live in fields and gardens: toads. When other kinds of animals of this group were discovered elsewhere, such as tree-frogs, fire-bellied toads, and others, it was realized that these various forms actually represented one major group. This group, the anurans, is now commonly referred to as frogs.
Frogs are amphibians, a term derived from two Greek words: amphi meaning double and bios meaning life. The double life of frogs involves living in water and also on land. Because of this amphibious habit, they must have adaptations for each environment. As in other animals that have a separate larval stage and a complex life cycle, frogs have two extremely different morphologies.
species calls eggs rana
Like other amphibians,
such as salamanders (order Caudata) and caecilians (order Gymnophiona), most
frogs hatch from a shell-less egg into a gilled, water-dwelling, larval stage
(a tadpole). After a period of growth they metamorphose into the adult form.
Most species of tadpoles are vegetarians, feeding upon algae and
other plant material. All adult frogs,
however, are carnivores, most of them feeding upon insects and other invertebrates.
In the temperate zones
of the world the breeding season begins in the spring, but the precise time depends
upon the species of frog. In much of temperate North America, for example, the beginning
of springtime is proclaimed by the breeding calls of chorus frogs (Pseudacris spp.).
Their high trills are soon followed by the calls of the spring peeper (Hyla
crucifer). These may be followed by the rasping calls of the wood frog
(Rana sylvatica), the leopard frog (Rana pipiens), and the green
frog (Rana clamitans). Then the American toad (Bufo americanus)
trills in, and when the larger ponds eventually warm up, the bullfrog (Rana
catesbeiana) begins its booming jug-of-rum calls. As many as 16 different
species of frogs have been found calling at various times at a single pond in
Florida.
The males of each frog species have their own distinctive call. It has recently been found that the ear of the female is "tuned" to the call of her own species, so that not only is she not attracted to the calls other species, she may not even hear them! A female carrying eggs will typically approach a calling male of her choice (and of her species), and nudge him. He immediately ceases calling and grasps her around the waist. They enter the water (if they are not already in it), and as she expels eggs from her cloaca, the male sprays sperm over them. Depending upon the species, the eggs may appear in strings, in clusters, or as individual ova.
The males of each frog species have their own distinctive call. It has recently been found that the ear of the female is "tuned" to the call of her own species, so that not only is she not attracted to the calls other species, she may not even hear them! A female carrying eggs will typically approach a calling male of her choice (and of her species), and nudge him. He immediately ceases calling and grasps her around the waist. They enter the water (if they are not already in it), and as she expels eggs from her cloaca, the male sprays sperm over them. Depending upon the species, the eggs may appear in strings, in clusters, or as individual ova.
The eggs are enclosed in
a protective jelly coating, and will develop over several days to a week into a
tadpole. The tadpole will grow over a period of time (weeks, months, or years,
depending upon the species), and ultimately sprouts legs, changes other
elements of its external and internal morphology, and emerges as a small
replica of the adult.
This sequence is typical
of frogs living in temperate regions. In the tropics breeding is often
initiated by a change in weather (such
as dry to wet), the calling males may be on the moist forest floor or in a tree, theA lesser
gray treefrog (Hyla versicolor) at Mahn-Go-Ta-See Camp, Michigan. The
lesser gray is the most widely distributed of the 13 species of North American
tree frogs. Photograph by Robert J. Huffman. Field Mark Publications.
Reproduced by permission.eggs may be laid on foliage or beneath a rock or in a
pond, and the tadpole stage may be completed inside the egg capsule, so that
froglets appear directly from the egg. In other words, there is enormous
variation in breeding habits, particularly in the tropics.
Source:
<a href="http://science.jrank.org/pages/2864/Frogs-Life-history-behavior.html">Frogs - Life History And Behavior</a>
<a href="http://science.jrank.org/pages/2864/Frogs-Life-history-behavior.html">Frogs - Life History And Behavior</a>
Read more: Frogs - Life History And Behavior - Species, Calls, Eggs, and Rana - JRank Articles http://science.jrank.org/pages/2864/Frogs-Life-history-behavior.html#ixzz4V1Nlkhqi-Life-history-behavior.html#ixzz4V1NUSJGL
rticles http://science.jrank.org/pages/2868/Frogs.html#ixzz4V1Qo2BbF
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