86 Percent of Earth's Species Still Unknown?

 

Even after centuries of effort, some 86 percent of Earth's species have yet to be fully described, according to new study that predicts our planet is home to 8.7 million species.
That means scientists have cataloged less than 15 percent of species now alive—and current extinction rates mean many unknown organisms will wink out of existence before they can be recorded.
The study was driven by a simple question: "Are we within reach of finding all species, or are we way off?" said study co-author Boris Worm of Canada's Dalhousie University.
"The answer is, we are way off."
Two hundred and fifty years after Swedish botanist Carl Linnaeus devised a formal system for classifying the diversity of nature, the catalog for some classes of living things—such as mammals and birds—is nearly complete, the study says. But the inventories for other classes are woefully sparse.
For instance, only 7 percent of the predicted number of fungi—which includes mushrooms and yeasts—has been described, and less than 10 percent of the life-forms in the world's oceans has been identified.
What's been discovered so far are "those things that are easy to find, that are conspicuous, that are relatively large," Worm said.
"There is an age of discovery ahead of us when we could find out so much more of what lives with us on this planet."
Counting Earth's Millions
So far, some 1.2 million species are known to science. To calculate the percentage of unknown species, Worm and colleagues first had to answer one of the great questions of ecology: How many species live on the Earth?
Previous guesses ranged from three million all the way to a hundred million. (See "'Encyclopedia of Life' to Catalog All Species on Earth.")
To gain a more precise answer, the authors examined the categories into which all species are grouped.
Scientists lump similar species together into a broader grouping called a genus, similar genera into a still broader category called a family, and so on, all the way up to a supercategory called a kingdom. (See photos of species classification in National Geographic magazine.)
There are five kingdoms: animals, plants, fungi, chromists—including one-celled plants such as diatoms—and protozoa, or one-celled organisms.
Worm's team estimated the total number of genera, families, orders, classes, and phyla—a designation above class—in each kingdom. That's a relatively easy task, since the number of new examples in these categories has leveled off in recent decades.
By contrast, the number of newly discovered species continues to rise sharply.
Using complex statistics, Worm and colleagues used the number of genera, families, and so on to predict Earth's number of unknown species, and their calculations gave them a number: 8.7 million.
An Issue of Statistics
Some experts called the research, published August 23 in the journal PLoS Biology, reasonable.
The new study "takes a hugely clever approach, and I think it's going to turn out to be a pretty important study," said Lucas Joppa, a conservation ecologist at Microsoft Research, the research branch of the software giant.
"If I asked you to count out 8.7 million pennies, that would take you a while, even if you had a whole lot of people doing it."
But Dan Bebber, an ecologist at the environmental group Earthwatch Institute, said the study relies on improper statistical methods.
The study team used a method called linear regression to calculate the number of Earth's species. But Bebber thinks this method is the wrong one for the data, and that the team should have used a technique known as ordinal regression.
As a result, the true number of species could be much higher or lower than 8.7 million, he said.
Nature's Library Disappearing
Overall, formally categorizing a new organism is a lot more complicated than discovering one, study co-author Worm said. Scientists must compare their specimen to museum samples, analyze its DNA, and complete reams of paperwork.
"It's a long process," he said. Most scientists "will describe dozens of species in their lifetime, if they're really lucky."
Unfortunately, extinction rates have accelerated to ten to a hundred times their natural level, Worm added.
(See "Extinctions Overestimated by 160 Percent?")
The information to be gained when new species are discovered "is nature's library, and we've only begun to decipher the first ten books," Worm said.
"We're throwing out entire books without having a look at them."

Source: National Geographical

Our children - Our responsibility

Are you watching your children?

87% of the parents don't know what their children doing online.

Thought the internet is a fascinating place where children learn, discover and have fun, it can also be a
place that is extremely dangerous in a few clicks away.

It seems 66% of children aged between 10-19 exposed to online pornography.

Excessive computer viewing can contribute to poor grades, sleep problems, behaviors problems, obesity and risky behavior.



As parents, it's our responsibility to make sure our children are safe online.

Our children - Our responsibility

How does a mongoose kill a snake?

When it comes to killing snakes. the mongoose is the world's champ. Let’s watch the scrappy fellow go through a bout. Our champ is the Indian mongoose. a relative of the Rikki tikki tavi in the Kipling Jungle Book story. It is early morning and time for breakfast. Mr. Mongoose. wearing a dark grey fur coat. sallies forth from his burrow. In looks you might mistake him for a kind of weasel„
He walks along gracefully. stopping to listen and stare around with bright red eyes' Ahl He sees a scorpion. Pounce. Mr. Mongoose is licking his chops! On he goes. hoping to find  snakes for he is very hungry: Shi Over there is just what our champ needs to start off his day:
It is a deadly. seven‑foot cobra. And our champ is no bigger than a house cat. The snake senses trouble and gets ready to strike. But Mr Mongoose has a trick ready. He fuzzes up the hair of his coat. This makes him look twice as big as he really is. The cobra doesn’t mind where he strikes so long as his fangs sink into meat. But with the mongoose he stands a good chance of grabbing only a mouthful of fur.
What’s more. his chances of getting even that are very slim. For our mongoose is very. very agile. His reactions are faster than those of the snake. He can leap out of range quicker than the snake can plan. The snake strikes and misses. He flops full length to the ground with a mouthful of empty air. Now the mongoose moves with a flash. He springs onto the prone snake and tries to sink his sharp teeth into the back of the head. He bites and springs back. Again the snake strikes short of his mark. Again he is rewarded for his trouble with a bite in the back of the neck.
The strikes go on and the bites begin to tell. Sooner or later the mongoose inflicts a mortal wound. He then begins to eat his fallen enemy. head first. poison glands and all. All that snake meat may be too much for one sitting. The mongoose may stuff himself curl up and take a snooze.
It takes time and a lot of effort for the snake to launch himself for each strike. Meantime the little mongoose is plotting the moves and getting set to spring nimbly out of the way. The little pink mouth is always open ready to take a nip and goad the snake into one useless lunge after another. After each strike. the snakes head and neck are flat on the ground. This is when the mongoose leaps in to take a nip at the back of his enemy’s head. The duel ends when the snake is so tired he can strike no more. Then the mongoose gives a killing bite and starts his dinner. He begins with the snake's head. devouring poison glands and all. After a while  he takes a nap then wakes up and goes right on with the feast.
As a mortal enemy of snakes the little mongoose is a valuable animal in his native lands. He also destroys rats. mice and other rodent pests. He can live in the wild or share life with a human family. In either case like a good farm cat  much of his time is spent fighting the enemies of his human friends.