Friday, December 31, 2010

insect pictures

Insects (from Latin insectum, a calque of Greek ἔντομον [éntomon], “cut into sections”) are a class within the arthropods that have a chitinous exoskeleton, a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes, and two antennae. They are among the most diverse group of animals on the planet and include more than a million described species and represent more than half of all known living organisms.[2][3] The number of extant species is estimated at between six and ten million,[2][4][5] and potentially represent over 90% of the differing metazoan life forms on Earth.[6] 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.

The life cycles of insects vary but most hatch from eggs. Insect growth is constrained by the inelastic exoskeleton and development involves a series of molts. The immature stages can differ from the adults in structure, habit and habitat and can include a passive pupal stage in those groups that undergo complete metamorphosis. Insects that undergo incomplete metamorphosis lack a pupal stage and adults develop through a series of nymphal stages.[7] The higher level relationship of the hexapoda is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm (22–28 in). The most diverse insect groups appear to have coevolved with flowering plants.

Insects typically move about by walking, flying or occasionally sinking and swimming at the same time. Because it allows for rapid yet stable movement, many insects adopt a tripedal gait in which they walk with their legs touching the ground in alternating triangles. Insects are the only invertebrates to have evolved flight. Many insects spend at least part of their life underwater, with larval adaptations that include gills and some adult insects are aquatic and have adaptations for swimming. Some species, like water striders, are capable of walking on the surface of water.

Insects are mostly solitary, but some insects, such as certain bees, ants, and termites are social and live in large, well-organized colonies. Some insects, like earwigs, show maternal care, guarding their eggs and young. Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over distances of many kilometers. Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyridae in the beetle order Coleoptera communicate with light.

Humans regard certain insects as pests and attempt to control them using insecticides and a host of other techniques. Some insects damage crops by feeding on sap, leaves or fruits, a few bite humans and livestock, alive and dead, to feed on blood and some are capable of transmitting diseases to humans, pets and livestock. Many other insects are considered ecologically beneficial and a few provide direct economic benefit. Silkworms and bees have been domesticated by humans for the production of silk and honey, respectively.
General body plan
Insects have segmented bodies supported by an exoskeleton, a hard outer covering made mostly of chitin. The segments of the body are organized into three distinctive but interconnected units, or tagmata: a head, a thorax, and an abdomen.[8] The head supports a pair of sensory antennae, a pair of compound eyes, and, if present, one to three simple eyes (or ocelli) and three sets of variously modified appendages that form the mouthparts. The thorax has six segmented legs—one pair each for the prothorax, mesothorax and the metathorax segments making up the thorax—and, if present in the species, two or four wings. The abdomen consists of eleven segments, though in a few species of insects these segments may be fused together or reduced in size. The abdomen also contains most of the digestive, respiratory, excretory and reproductive internal structures.[9]:22–48 There is considerable variation and many adaptations in the body parts of insects especially wings, legs, antenna, mouth-parts etc.

[edit] Exoskeleton
Insect outer skeleton, the cuticle, is made up of two layers: the epicuticle, which is a thin and waxy water resistant outer layer and contains no chitin, and a lower layer called the procuticle. The procuticle is chitinous and much thicker than the epicuticle and has two layers: an outer layer known as the exocuticle and an inner layer known as the endocuticle. The tough and flexible endocuticle is built from numerous layers of fibrous chitin and proteins, criss-crossing each others in a sandwich pattern, while the exocuticle is rigid and hardened.[9]:22–24 The exocuticle is greatly reduced in many soft-bodied insects (e.g., caterpillars), especially during their larval stages.
Insects are the only invertebrates to have developed active flight capability, and this has played an important role in their success.[9]:186 These muscles are able to contract multiple times for each single nerve impulse, allowing the wings to beat faster than would ordinarily be possible. Having their muscles attached to their exoskeletons is more efficient and allows more muscle connections; crustaceans also use the same method, though all spiders use hydraulic pressure to extend their legs, a system inherited from their pre-arthropod ancestors. Unlike insects, though, most aquatic crustaceans are biomineralized with calcium carbonate extracted from the water.[10][11]
[edit] Nervous system
The nervous system of an insect can be divided into a brain and a ventral nerve cord. The head capsule, made up of six fused segments, each with a pair of ganglia, or a cluster of nerve cells outside of the brain. The first three pairs of ganglia are fused into the brain, while the three following pairs are fused into a structure of three pairs of ganglia under the insect's esophagus, called the subesophageal ganglion.[9]:57





Sunday, December 26, 2010

snakes pictures

snakes pictures
snakes pictures
snakes pictures
snakes pictures
snakes pictures
snakes pictures
snakes pictures

Friday, December 24, 2010

cassowary birds world most dangerous birds

The cassowary (genus Casuarius) is a very large flightless bird native to the tropical forests of New Guinea, nearby islands and northeastern Australia.[2]

The Southern Cassowary is the third tallest and second heaviest living bird, smaller only than the ostrich and emu.

Cassowaries feed mainly on fruits, though all species are truly omnivorous and will take a range of other plant food including shoots, grass seeds, and fungi in addition to invertebrates and small vertebrates.

Cassowaries are very shy, but when disturbed, they are capable of inflicting serious injuries to dogs and children
cassowary birds
cassowary birds
cassowary birds
Cassowaries (from the Malay name kesuari)[3] are part of the ratite group, which also includes the Emu, rheas, ostriches, and kiwis, and the extinct moas and elephant birds. There are three extant species recognized today and one extinct:

Casuarius casuarius, Southern Cassowary or Double-wattled Cassowary, found in southern New Guinea, northeastern Australia, and the Aru Islands,[2] mainly in lowlands.
Casuarius bennetti, Dwarf Cassowary or Bennett's Cassowary, found in New Guinea, New Britain, and on Yapen,[2] mainly in highlands.
Casuarius unappendiculatus, Northern Cassowary or Single-wattled Cassowary, found in the northern and western New Guinea, and Yapen,[2][4] mainly in lowlands.
Casuarius lydekki Extinct[1]
Presently, most authorities consider the above monotypic, but several subspecies have been described of each (some have even been suggested as separate species, e.g., C. (b) papuanus).[4] It has proven very difficult to confirm the validity of these due to individual variations, age-related variations, the relatively few available specimens (and the bright skin of the head and neck–the basis of which several subspecies have been described–fades in specimens), and that locals are known to have traded live cassowaries for hundreds, if not thousands, of years, some of which are likely to have escaped or deliberately introduced to regions away from their origin.[4]
cassowary birds
cassowary birds
cassowary birds
cassowary birdsThe Northern and Dwarf Cassowaries are not well known. All cassowaries are usually shy birds of the deep forest, adept at disappearing long before a human knows they are there. Even the more accessible Southern Cassowary of the far north Queensland rain forests is not well understood.

Females are bigger and more brightly coloured. Adult Southern Cassowaries are 1.5 to 1.8 metres (59–71 in) tall, although some females may reach 2 metres (79 in),[5] and weigh 58.5 kilograms (129 lb).[6]
All cassowaries have feathers that consist of a shaft and loose barbules. They do not have retrices (tail feathers) or a preen gland. Cassowaries have small wings with 5-6 large remeges. These are reduced to stiff, keratinous quills, like porcupine quills, with no barbs.[6] A claw is on each second finger.[7] The furcula and coracoid are degenerate, and their palatal bones and sphenoid bones touch each other.[8] These, along with their wedge-shaped body, are thought to be adaptations to ward off vines, thorns and saw-edged leaves, allowing them to run quickly through the rainforest.[
cassowary birds
cassowary birds
cassowary birds

Tuesday, December 21, 2010

tiger snakes pictures

tiger snakes pictures
tiger snakes pictures
tiger snakes pictures
tiger snakes pictures
tiger snakes pictures
tiger snakes pictures
tiger snakes pictures
tiger snakes pictures
tiger snakes pictures
tiger snakes pictures

Sunday, December 19, 2010

dangerous animals

Which animals kill the most people in the wild?
by Debra Ronca

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Ronca, Debra. "Which animals kill the most people in the wild?" 15 December 2008. HowStuffWorks.com. 19 December 2010.
Inside this Article
Which animals kill the most people in the wild?
The Most Deadly Animals: Mosquitoes
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Sources

"A-Z Animal Directory." National Geographic. 2008. (Dec. 4, 2008)
http://animals.nationalgeographic.com/animals/a-to-z
Bailey, Ronald. "North America's Most Dangerous Mammal." Reason Online. Nov. 21, 2001. (Dec. 4, 2008)
http://www.reason.com/news/show/34914.html
"Bear Attack Statistics for USA & Canada." Black Bear Heaven. 2008. (Dec. 4, 2008)
http://www.blackbearheaven.com/bear-attack-statistics.htm
"CDC Activities." Centers for Disease Control and Prevention. Jun. 2, 2006. (Dec. 4, 2008)
http://www.cdc.gov/malaria/cdcactivities/index.htm
"Dengue and dengue haemorrhagic fever." World Health Organization. May 2008. (Dec. 4, 2008)
http://www.who.int/mediacentre/factsheets/fs117/en/
"Destinations." Centers for Disease Control and Prevention. Nov. 5, 2008. (Dec. 4, 2008)
http://wwwn.cdc.gov/travel/destinationList.aspx
"Eradication of Malaria in the United States (1947-1951). Centers for Disease Control and Prevention. April 23, 2004. (Dec. 4, 2008)
http://www.cdc.gov/malaria/history/eradication_us.htm
"Hippopotamus." Destination Kruger Park. 2008. (Dec. 4, 2008)
http://www.krugerpark.co.za/africa-hippopotamus.html
"Hippopotamus." How Stuff Works. April 23, 2008. (Dec. 4, 2008)
http://animals.howstuffworks.com/mammals/hippopotamus-info.htm
Long, Dr. Douglas. "The Great White Shark." University of California Museum of Paleontology. 2008. (Dec. 4, 2008)
dangerous animals
dangerous animals
dangerous animals
dangerous animals
dangerous animals

Saturday, December 18, 2010

sun bears pictures

sun bears pictures
sun bears pictures
sun bears pictures
sun bears pictures
sun bears pictures
sun bears
sun bears
sun bears
sun bears

Monday, December 13, 2010

devils flowers mantis

Flower Mantis is a common name given to various species of praying mantis that mimic flowers including:

Acromantis formosana (Taiwan flower mantis[1])
Blepharopsis mendica (devil's flower mantis[2], Egyptian flower mantis [3])
Chloroharpax modesta (Nigerian flower mantis [4] )
Creobroter gemmatus (jewelled flower mantis [5][6])
Creobroter pictipennis (Indian flower mantis [5][6])
Idolomantis diabolica (giant devil's flower mantis [7])
Pseudoharpax Virescens (Gambian spotted-eye flower mantis [8])
Theopropus elegans (banded flower mantis[2][9])
devils flowers mantis
devils flowers mantis
devils flowers mantis
devils flowers mantis
devils flowers mantis
devils flowers mantis
devils flowers mantis
devils flowers mantis
devils flowers mantis

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