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Archive for October, 2008

Virgin Birth in Sharks

October 10th, 2008 No comments

There is a very interesting article today at MSNBC.com about virgin births in sharks. Yes, that’s correct…scientiests have found another instance where a pup carried by a female Atlantic blacktip shark contained absolutely no male genetic material at all.

This is the second documented case of parthenogenesis, or asexual reproduction, in sharks. The first instance occured at a zoo in Omaha, NE.

The medical mystery began 16 months ago after the death of the Atlantic blacktip shark named Tidbit at the Virginia Beach aquarium. No male blacktip sharks were present during her eight years at the aquarium.

In May 2007, the 5-foot, 94-pound shark died of stress-related complications related to her unknown pregnancy after undergoing a yearly checkup. The 10-inch shark pup was found during a necropsy of Tidbit, surprising aquarium officials. They initially thought the embryonic pup was either a product of a virgin birth or a cross between the blacktip and a male of another shark species — which has never been documented, Chapman said.

Tidbit’s pup was nearly full term, and likely would have been quickly eaten by “really big sand tiger sharks” that were in the tank, Chapman said in a telephone interview from Florida.

That is what happened to the tiny hammerhead pup in the Omaha case.

“By the time they could realize what they were looking at, something munched the baby,” he said of aquarium workers. The remains of the pup were used for the DNA testing.

Virgin birth has been proven in other species, including some bony fish, amphibians, reptiles and birds.

Absent the chromosomes present in the male sperm, the offspring of an asexual conception have reduced genetic diversity and, the scientists said, may be at a disadvantage for surviving in the wild. A pup, for instance, can be more susceptible to congenital disorders and diseases.

Scientists speculate that such births could become more common if population densities become so low that female sharks have problems finding partners.

Categories: Science, Weird Tags: , , ,

What Is The Law Of Parsimony?

October 9th, 2008 No comments

The law of parsimony, also called the law of economy or Ockham’s razor, proposes that a problem should be stated in its basic and simplest terms. In scientific terms, it states that the simplest theory that fits the facts of a problem should be the one selected. Credit for outlining the law is usually give to William of Ockham (1284? – 1347?), an English philosopher and theologian, who wrote that “entities must not be multiplied beyond what is necessary.”

[Source : The Handy Science Answer Book]

Categories: Science Tags: ,

When Did The Concept Of The Square Root Originate?

October 8th, 2008 No comments

The concept of the square root has been in existance for many thousands of years. Exactly how it was discovered is unknown, but several different methods of exacting square roots were used by early mathematicians. Babylonian clay tablets from 1900 to 1600 BCE contain the squares and cubes of integers 1-30. The early Egyptians used square roots around 1700 BCE, and during the Greek Classical Period (600-300 BCE) better arithmetic methods improved square root operations. The 16th century, French mathematician Rene Descartes was the first to use the square root symbol.

Categories: Science Tags: , ,

Who Invented Stainless Steel?

October 7th, 2008 No comments

Metallurgists in several countries developed stainless steel between 1903 and 1912. An American, Elwood Haynes, developed several alloy steels and in 1911 produced stainless steel. Harry Brearly of Great Britain receives most of the credit for its development. Frederick Beckett, a Canadian-American metallurgist and German scientists P. Monnartz and W. Borchers were amount early developers.

[Source : The Handy Science Answer Book]

Categories: Science Tags: , ,

Did Dinosaurs And Humans Ever Coexist?

October 6th, 2008 No comments

No. Dinosaurs first appeared during the Triassic Period (about 220 million years ago) and disappeared at the end of the Cretaceous Period (about 65 million years ago). Modern humans (Homo sapiens) appeared only about 25,000 years ago.

[Source : The Handy Science Answer Book]

Categories: Science Tags: , ,

How Many Species Of Insects Are There?

October 5th, 2008 No comments

Estimates of the number of recognized insect species range from about 750,000 to upward of one million – but some experts think that this represents less than half of the number that exists in the world. About 7,000 new species are described each year, but unknown numbers are lost annually from the destruction of their habitats, mainly tropical forests.

[Source : The Handy Science Answer Book]

Categories: Science Tags: , , ,

What Is The Basic Unit Of The Brain?

October 4th, 2008 No comments

Neurons are the nerver cells that are the major constituent of the brain. At birth the brain has the maximum number of neurons – 20 billion to 200 billions neurons. Thousands are lost daily, never to be replaced, and apparently not missed, until the cumulative loss builds up in very old age.

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Do All Animals Have Red Blood?

October 3rd, 2008 No comments

The color of blood is related to the compounds that transport oxygen. Hemoglobin, containing iron, is red and found in all vertebrates (animals having a backbone) and a few invertebrates (animals lacking a backbone). Annelids (segmented worms) have either a green pigment, chlorocruorin, or a red pigment, hemerythrin. Some crustaceans (arthropods having divided bodies and generally having gills) have a blue pigment, hemocyanin, in their blood.

[Source : The Handy Science Answer Book]

Why Is Seven A Magical Number?

October 2nd, 2008 No comments

In magical lore and mysticism, all numbers are ascribed certain properties and energies. Seven is a number of great power, a magical number, a lucky number, a number of psychic and mystical powers, of secrecy and the search for inner truth. The origin of belief in seven’s powers lies in the lunar cycle. Each of the moon’s four phases lasts about seven days. The Summerians, who based their calendar on the moon, gave the week seven days and declared the seventh and last day of each week to be uncanny. Life cycles on Earth also have phases demarcated by seven, there are said to be seven years to each stage of human growth, and there are seven colors to the rainbow, seven notes in the musical scale, seven petitions to the Lord’s Prayer, and seven deadly sins. The seventh son of a seventh son is said to be born with formidable magical and psychic powers. The number seven is widely held to be a lucky number, especially in matters of love and money.

[Source : The Handy Science Answer Book]

What Was The First Successful Video-Arcade Game?

October 1st, 2008 No comments

Pong, a simple electronic version of a tennis game, was the first successful video-arcade game. First marketed in 1972, Pong was actually invented 14 years earlier in 1958 by William Higinbotham, who headed instrumentation design at Brookhaven National Laboratory at the time. Invented to amuse visitors touring the laboratory, the game was so popular that visitors would stand in line for hours to play it. Higinbotham dismantled the system two years later, and, considering it a trifle, did not patent it. In 1972, Atari released Pong, an arcade version of Higinbotham’s game, and Magnavox released Odyssey, a version that could be played on home televisions.

Categories: Computing, Technology Tags: , ,