A cobra is a venomous snake, which is a member of the family Elapidae (elapids). The name is short for cobra de capelo (or cobra di capello), which is Portuguese for "snake with hood," or "hood-snake."[1] When disturbed, most of these snakes can rear up and spread their neck (or hood) in a characteristic threat display. However, not all snakes referred to as cobras are of the same genus, or even of the same family.
Cobra may refer to:
Any member of the genus Naja, a.k.a. typical cobras (with the characteristic ability to raise the front quarters of their bodies off the ground and flatten their necks in a threatening gesture), a group of venomous elapids found in Africa and Asia.
Any member of the genus Boulengerina, a.k.a. water cobras, a group of venomous elapids found in Africa.
Any member of the genus Aspidelaps, a.k.a. shield-nosed cobras or coral snakes, a group of venomous elapids found in Africa.
Any member of the genus Pseudohaje, a.k.a. tree cobras, a group of venomous elapids found in Africa.
Paranaja multifasciata, a.k.a. the burrowing cobra, a venomous elapid species found in Africa.
Ophiophagus hannah, a.k.a. the king cobra, a venomous elapid species found in India and southern Asia.
Hemachatus haemachatus, a.k.a. the spitting cobra or ringhals, a venomous elapid species found in Africa.
Micrurus fulvius, a.k.a. the American cobra or eastern coral snake, a venomous elapid species found in the southeastern United States.
Hydrodynastes gigas, a.k.a. the false water cobra, a mildly venomous colubrid species found in South America.
A taxonomic synonym for the genus Bitis, a.k.a. puff adders, a group of venomous vipers found in Africa and in the south of the Arabian Peninsula.
Tuesday, September 15, 2009
A white tiger is a tiger with a recessive gene that creates the pale coloration.
A white tiger is a tiger with a recessive gene that creates the pale coloration. Another genetic characteristic makes the stripes of the tiger very pale; white tigers of this type are called snow-white or "pure white". This occurs when a tiger inherits two copies of the recessive gene for the paler coloration, which is rare. They have a pink nose, pink paw pads, grey-mottled skin, ice-blue eyes, and white to cream-coloured fur with black, ash grey, or chocolate-coloured stripes. Mr. H.E. Scott of the Indian police gave this description of a captive white tiger's eyes: "The colourings of the eyes are very distinct. There is no well defined division between the yellow of the comex and the blue of the iris. The eyes in some lights are practically colourless merely showing the black pupil on a light yellow background."[1]
White tigers are not albinos and do not constitute a separate subspecies of their own and can breed with orange ones, although all of the resulting offspring will be heterozygous for the recessive white gene, and their fur will be orange. The only exception would be if the orange parent was itself already a heterozygous tiger, which would give each cub a 50% chance of being either double-recessive white or heterozygous orange. If two heterozygous tigers, or heterozygotes, breed on average 25% of their offspring will be white, 50% will be heterozygous orange (white gene carriers) and 25% will be homozygous orange, with no white genes. In the 1970s a pair of heterozygous orange tigers named Sashi and Ravi produced 13 cubs in Alipore Zoo, of which 3 were white.[2] If two white tigers breed, 100% of their cubs will be homozygous white tigers. A tiger which is homozygous for the white gene may also be heterozygous or homozygous for many different genes. The question of whether a tiger is heterozygous (a heterozygote) or homozygous (a homozygote) depends on the context of which gene is being discussed. Inbreeding promotes homozygosity and has been used as a strategy to produce white tigers.
Compared to orange tigers without the white gene, white tigers tend to be larger both at birth and at full adult size.[3] This may have given them an advantage in the wild despite their unusual coloration. Heterozygous orange tigers also tend to be larger than other orange tigers. Kailash Sankhala, the director of the New Delhi Zoo in the 1960s, said "One of the functions of the white gene may have been to keep a size gene in the population, in case it's ever needed."[4]
Dark-striped white individuals are well-documented in the Bengal Tiger subspecies, also known as the Royal Bengal or Indian tiger, (Panthera tigris tigris or P. t. bengalensis), may also have occurred in captive Siberian Tigers (Panthera tigris altaica), and may have been reported historically in several other subspecies. White pelage is most closely associated with the Bengal, or Indian subspecies. Currently, several hundred white tigers are in captivity worldwide with about 100 of them in India, and their numbers are on the increase. The modern population includes both pure Bengals and hybrid Bengal–Siberians, but it is unclear whether the recessive gene for white came only from Bengals, or from any of the Siberian ancestors as well.
The unusual coloration of white tigers has made them popular in zoos and entertainment that showcases exotic animals. The magicians Siegfried & Roy are famous for having bred and trained two white tigers for their performances, referring to them as "royal white tigers" perhaps from the white tiger's association with the Maharaja of Rewa.
White tigers are not albinos and do not constitute a separate subspecies of their own and can breed with orange ones, although all of the resulting offspring will be heterozygous for the recessive white gene, and their fur will be orange. The only exception would be if the orange parent was itself already a heterozygous tiger, which would give each cub a 50% chance of being either double-recessive white or heterozygous orange. If two heterozygous tigers, or heterozygotes, breed on average 25% of their offspring will be white, 50% will be heterozygous orange (white gene carriers) and 25% will be homozygous orange, with no white genes. In the 1970s a pair of heterozygous orange tigers named Sashi and Ravi produced 13 cubs in Alipore Zoo, of which 3 were white.[2] If two white tigers breed, 100% of their cubs will be homozygous white tigers. A tiger which is homozygous for the white gene may also be heterozygous or homozygous for many different genes. The question of whether a tiger is heterozygous (a heterozygote) or homozygous (a homozygote) depends on the context of which gene is being discussed. Inbreeding promotes homozygosity and has been used as a strategy to produce white tigers.
Compared to orange tigers without the white gene, white tigers tend to be larger both at birth and at full adult size.[3] This may have given them an advantage in the wild despite their unusual coloration. Heterozygous orange tigers also tend to be larger than other orange tigers. Kailash Sankhala, the director of the New Delhi Zoo in the 1960s, said "One of the functions of the white gene may have been to keep a size gene in the population, in case it's ever needed."[4]
Dark-striped white individuals are well-documented in the Bengal Tiger subspecies, also known as the Royal Bengal or Indian tiger, (Panthera tigris tigris or P. t. bengalensis), may also have occurred in captive Siberian Tigers (Panthera tigris altaica), and may have been reported historically in several other subspecies. White pelage is most closely associated with the Bengal, or Indian subspecies. Currently, several hundred white tigers are in captivity worldwide with about 100 of them in India, and their numbers are on the increase. The modern population includes both pure Bengals and hybrid Bengal–Siberians, but it is unclear whether the recessive gene for white came only from Bengals, or from any of the Siberian ancestors as well.
The unusual coloration of white tigers has made them popular in zoos and entertainment that showcases exotic animals. The magicians Siegfried & Roy are famous for having bred and trained two white tigers for their performances, referring to them as "royal white tigers" perhaps from the white tiger's association with the Maharaja of Rewa.
Wednesday, September 2, 2009
How to Reset an iPod
Is your iPod frozen and you can't get it to work? Want to change that? Here's how.
[edit] Steps
- Toggle the Hold switch. On most iPods you can just toggle the Hold switch backwards and forwards three times in rapid succession. This snaps your iPod out of a minor freeze.
- Plug it in. Plugging it into a computer or A/C power outlet can snap an iPod out of a freeze.
- Reset the iPod. You can reset your iPod by holding down the Center button and the Select button (at the bottom of the wheel) or if your using an ipod nano, use the center button and the menu button. Hold it for about 10 seconds. iPod should power down, and then start back up again. Restarting takes a few moments, so be patient. If it doesn't work the first time, try it again. Laying it down flat map help it to reset. Also make sure that you are not touching any part of the Click-Wheel except the button you're pressing. This does not erase the contents of your iPod, it only reboots it.
- Try a different USB hub. If your computer is not recognizing that you've plugged an iPod into it, just try a different USB port, or a different cable.
- Make sure to try all the above steps. If nothing works, put it somewhere you will remember, plug in some speakers and leave it. Within a couple of hours it will run out of power. When it does, do not try to turn it back on. Plug it into a power source. This will restart the iPod completely, and you will have it back.
- Restore the iPod. If even that last step doesn't work, plug it in to a computer and Restore it to factory settings. This will wipe your iPods contents, and replace them with a blank iPod. If you have no back-ups, then this is not a preferable situation.
- If you wish to restore your iPod, however it will not connect to the computer...
- Hold down menu and the center key until the Apple logo comes up on screen
- Immediately when the Apple logo comes up on the screen, hold down the play key and the center key together. This puts your iPod in to DISK MODE.
- You should now be able to connect your iPod to the computer. Open iTunes, select the iPod in the left hand menu then select the restore function
- Also, for nano video, press and hold the middle button and the menu button together, it will go black, then keep holding it down, until you see a gray apple logo, then wait for it to go back to the menu page.
[edit] Tips
- None of the above steps (Except Restore) will wipe any information off your iPod. If your iPod is corrupted, it will be because of something either you did wrong or some corrupted file you put on it.
- If you plug in your iPod and it says "iPod is corrupt, you may need to restore it", do not restore it. Unplug it and try to reset it. Restoring it will wipe your iPod, and you won't have a chance to back-up the files.
- Always keep back-ups of all your music. That way you can just restore your iPod when something goes haywire, and it you can put it all back on there.
- Make sure the iPod is frozen. Normally if an iPod isn't starting up, it's just out of power. Plug it in to charge. If it freezes while you use it, or when you remove it or plug it in to a computer, then you have a freeze.
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