Tuesday 15 October 2013
Birds Picture Collection I
Birds Picture Collection I
INFORMATION :
Birds (class Aves or clade Avialae) are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. With around 10,000 living species, they are the most speciose class of tetrapod vertebrates. All present species belong to the subclass Neornithes, and inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) Ostrich. Thefossil record indicates that birds emerged within theropod dinosaurs during the Jurassic period, around 150 million years ago. Birds are the only members of the clade originating with the earliest dinosaurs to have survived the Cretaceous–Paleogene extinction event 66 million years ago.
Modern birds are characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All living species of birds have wings; the most recent species without wings was the moa, which is generally considered to have become extinct in the 16th century. Wings are evolved forelimbs, and most bird species can fly. Flightless birds include ratites, penguins, and a number of diverse endemic island species. Some species of birds, particularly penguins and members of the Anatidae family, are adapted to swim. Birds also have unique digestive and respiratory systems that are highly adapted for flight. Some birds, especially corvids and parrots, are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.
Many species undertake long distance annual migrations, and many more perform shorter irregular movements. Birds are social; they communicate using visual signals and through calls and songs, and participate in social behaviours, including cooperative breeding and hunting, flocking, and mobbingof predators. The vast majority of bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, but rarely for life. Other species have polygynous ("many females") or, rarely, polyandrous ("many males") breeding systems. Eggs are usually laid in a nest andincubated by the parents. Most birds have an extended period of parental care after hatching.
Many species are of economic importance, mostly as sources of food acquired through hunting or farming. Some species, particularly songbirds andparrots, are popular as pets. Other uses include the harvesting of guano (droppings) for use as a fertiliser. Birds figure prominently in all aspects of human culture from religion to poetry to popular music. About 120–130 species have become extinct as a result of human activity since the 17th century, and hundreds more before then. Currently about 1,200 species of birds are threatened with extinction by human activities, though efforts are underway to protect them.
Monday 14 October 2013
Pet Animals Cat Picture Collection I
Pet Animals CAT Picture Collection I
INFORMATION ABOUT CAT:
The domestic cat (Felis catus or Felis
silvestris catus) is a small, usually furry, domesticated,
and carnivorous mammal. It is often called
the housecat when kept as an indoor pet, or simply the cat when there is no need to distinguish
it from other felids and felines. Cats are often
valued by humans for companionship and their ability to hunt vermin and household pests.
Cats are
similar in anatomy to the other felids, with strong,
flexible bodies, quick reflexes, sharp retractable claws, and teeth adapted to
killing small prey. Cat senses fit a crepuscular and predatory ecological niche.
Cats can hear sounds too faint or too high in frequency for human ears, such as those made by
mice and other small animals. They can see in near darkness. Like most other
mammals, cats have poorer color visionand
a better sense of smell than humans.
Despite
being solitary hunters, cats are a social species, and cat
communication includes
the use of a variety of vocalizations (meowing, purring,trilling,
hissing, growling and grunting) as well as cat pheromones and types of cat-specific
body language.
Cats have
a rapid breeding rate. Under controlled breeding, they can be bred and shown as registered pedigree pets, a hobby known as cat fancy.
Failure to control the breeding of pet cats by spaying and neutering, and the abandonment of former
household pets, has resulted in large numbers of feral cats worldwide, requiring population control.
Since
cats were cult animals in ancient Egypt, they were
commonly believed to have been domesticated there, but there may have been instances of
domestication as early as the Neolithic from around 9500 years ago (7500 BC).
A genetic
study in 2007 revealed that domestic cats are descended from African wildcats (Felis silvestris lybica) c.
8000 BC, in the Middle East. According to Scientific American, cats are the most
popular pet in the world, and are now found almost every place where people
live.