Sunday, 6 November 2011

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate (or craniate) animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups.



Birds

Know About Birds

We can see birds in all parts of the world. They can be found in rainforests, oceans and desserts. Most birds can soar up in the sky, while penguins may dive to the depth of over 250 metres. the eating habits vary from bird to bird. Some of them eat only plants and some only feed on only fresh meat.











Birds (class Aves) are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. 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 now extinct flightless Moa of New Zealand was the only exception. Wings are evolved forelimbs, and most bird species can fly, with some exceptions, including ratites, penguins, and a number of diverse endemic island species. 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.




Seabirds

Seabirds (also known as marine birds) are birds that have adapted to life within the marine environment. In general, seabirds live longer, breed later and have fewer young than other birds do, but they invest a great deal of time in their young. Most species nest in colonies, which can vary in size from a few dozen birds to millions. Many species are famous for undertaking long annual migrations, crossing the equator or circumnavigating the Earth in some cases. They feed both at the ocean's surface and below it, and even feed on each other. Seabirds can be highly pelagic, coastal, or in some cases spend a part of the year away from the sea entirely.













Hunting birds

Hunting birds are also known as 'birds of prey'. Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh. In most cases, the females are considerably larger than the males.
Using this cluster of anatomical and behavioural features, the species listed below are usually known to be birds of prey in ornithology. They can be divided into species that hunt during daylight, the raptors, and into species that hunt during the night, the owls. The raptors and the owls are distantly related and are classified in separate orders; however, their evolution has been convergent, both groups of birds adapting to a predatory lifestyle.



Saturday, 5 November 2011

Invertebrates are animals without backbones such as :

Insects
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body, three pairs of jointed legscompound eyes, and two antennae. They are among the most diverse groups of animals on the planet, including more than a million described species and represent more than half of all known living organisms. The number of extant species is estimated at between six and ten million. Insects may be found in nearly all environments, although only a small number of species occur in the oceans, a habitat dominated by another arthropod group, the crustaceans.





Squids
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles. Squid are strong swimmers and certain species can 'fly' for short distances out of the water. 








Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snailsland snails and freshwater snails. The word snail without any qualifier is however more often applied to land snails than to those from the sea or freshwater. Snail-like animals that naturally lack a shell, or have only an internal shell, are often called slugs, and land species that have only a very small shell (that they cannot retract into) are called semislugs. The three species of the Giant African land snail Achatina fulica can grow to be 15 in (38 cm) from snout to tail, and weigh 1 kilogram (2 lb). The largest living species of sea snail is Syrinx aruanus which has a shell that can measure up to 90 cm (35 in) in length, and the whole animal with the shell can weigh up to 18 kg (40 lb)
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Earthworm
Earthworm is the common name for the largest members of Oligochaeta (which is either a class or subclass depending on the author) in the phylumAnnelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female. Theoretical cladistic studies have placed them instead in the suborder Lumbricina of the order Haplotaxida, but this may again soon change. 




Sea Cucumber
Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. There are a number of holothurian species and genera, many of which are targeted for human consumption. The harvested product is variously referred to as trepang, bĂȘche-de-mer or balate.Like all echinoderms, sea cucumbers have an endoskeleton just below the skin, calcified structures that are usually reduced to isolated microscopic ossicles (or sclerietes) joined by connective tissue.



Jellyfish
Jellyfish (also known as jellies or sea jellies or a stage of the life cycle of Medusozoa) are free-swimming members of the phylum Cnidaria. Medusa is another word for jellyfish, and refers to any free-swimming jellyfish stages in the phylum Cnidaria. Jellyfish have several different morphologies that represent several different cnidarian classes including the Scyphozoa (over 200 species), Staurozoa (about 50 species), Cubozoa (about 20 species), and Hydrozoa(about 1000–1500 species that make jellyfish and many more that do not).
Jellyfish are found in every ocean, from the surface to the deep sea. Some hydrozoan jellyfish, or hydromedusae, are also found in fresh water; freshwater jellyfish are less than an inch (25 mm) in diameter, are colorless and do not sting. Large, often colorful, jellyfish are common in coastal zones worldwide. Scientists have evidence of jellyfish roaming the seas for about 500 million years.
In its broadest sense, the term jellyfish also generally refers to members of the phylum Ctenophora. Although not closely related to cnidarian jellyfish, ctenophores are also free-swimming planktonic carnivores, are generally transparent or translucent, and exist in shallow to deep portions of all the world's oceans.
Alternative names for groups of jellyfish are scyphomedusae, stauromedusae, cubomedusae, and hydromedusae. These may relate to an entire order or class.