TIL – A (3)

Other life-forms

The origin of life is one of the great unsolved problems of science. Nobody knows how, where or when life originated. About all that is known for certain is that microbial life had established itself on Earth by about three and a half billion years ago. In the absence of hard evidence of what came before, there is plenty of scope for disagreement. Thirty years ago the prevailing view among biologists was that life resulted from a chemical fluke so improbable it would be unlikely to have happened twice in the observable universe. That conservative position was

exemplified by Nobel Prize–winning French biologist Jacques Monod, who wrote in 1970: “Man at last knows that he is alone in the unfeeling immensity of the universe, out of which he emerged only by chance.” In recent years, however, the mood has shifted dramatically. In 1995

renowned Belgian biochemist Christian de Duve called life “a cosmic imperative” and declared “it is almost bound to arise” on any Earth-like planet. De Duve’s statement reinforced the belief among astrobiologists that the universe is teeming with life. Dubbed biological determinism by

Robert Shapiro of New York University, this theory is sometimes expressed by saying that “life is written into the laws of nature.” How can scientists determine which view is correct? The most direct way is to seek evidence for life on another planet, such as Mars. If life originated

from scratch on two planets in a single solar system, it would decisively confirm the hypothesis of biological determinism. Unfortunately, it may be a long time before missions to the Red Planet are sophisticated enough to hunt for Martian life-forms and, if they indeed exist, to study such extraterrestrial biota in detail. An easier test of biological determinism may be possible, however. No planet is more Earthlike than Earth itself, so if life does emerge readily

under terrestrial conditions, then perhaps it formed many times on our home planet. To pur sue this tantalizing possibility, scientists have begun searching deserts, lakes and caverns for evidence of “alien” life-forms—organisms that would differ fundamentally from all known living

creatures because they arose independently. Scientists have yet to reach a consensus on a strict definition of life, but most would agree that two of its hallmarks are an ability to metabolize (to draw nutrients from the environment, convert those nutrients into energy and excrete waste products) and an ability to reproduce. The orthodox view of biogenesis holds that if life on Earth originated more than once, one form would have swiftly predominated and eliminated all the others. This extermination might have happened, for example, if one form quickly appropriated all the available resources or “ganged up” on a weaker form of life by swapping successful genes exclusively with its own kind. But this argument is weak. Bacteria and archaea, two very different types of microorganisms that descended from a common ancestor more than three billion years ago, have peacefully coexisted ever since, without one eliminating the other. Moreover, alternative forms of life might not have directly competed with known organisms, either because the aliens occupied extreme environments where familiar microbes could not survive or because the two forms of life required different resources. Even if alternative life does not exist now, it might have flourished in the distant past before dying out for some reason. In that case, scientists might still be able to find markers of their extinct biology in the geologic record. If alternative life had a distinctively different metabolism, say, it might have altered rocks or created mineral deposits in a way that cannot be explained by the activities of known organisms. Biomarkers in the form of distinctive organic molecules that could not have been created by familiar life might even be hiding in ancient microfossils, such as those found in rocks dating from the Archean era (more than 2.5 billion years ago). A more exciting but also more speculative possibility is that alternative life-forms have survived and are still present in the environment, constituting a kind of shadow biosphere. At first this idea might seem preposterous; if alien organisms thrived right under our noses (or even in our noses), would not scientists have discovered them already? It turns out that the answer is no. The vast majority of organisms are microbes, and it is almost impossible to tell what they are simply by looking at them through a microscope. Microbiologists must analyze the genetic sequences of an organism to determine its location on the tree of life—the phylogenetic grouping of all known creatures—and researchers have classified only a tiny fraction of all observed microbes.

We speak of life: (see text )

An alien life-form is: (see text )Deselect Answer

The studies on the most ancient geological strata: (see text)Deselect Answer

According to biological determinism, life: (see text )Deselect Answer

Arnold Schwarzenegger was the governor of which American state?

Which actor played Rocky?

Which building was not attacked on 9/11?

What is the capital city of Australia?

A robot is programmed to apply the following instructions in order to move through a maze:

• If it is possible to move forwards, then move one space forwards
• If it is not possible to move forwards, then keep turning right until it is possible to move forwards again.

The robot is placed in the square at the bottom left of the maze (marked R on the diagram).

How many of the squares will the robot move through before leaving the maze?

The table below shows the prices that a supplier charges for exercise books. For each size of the price per book depends on the total number in order.

How much would it cost to buy 300 medium exercise books?

The picture below shows a tiled floor where 24 individual tiles with different printing on them are used to make up the overall pattern.

How many different patterns of tile are needed to make up the overall pattern?

A word game involves making words from random letters. Letters in a word can score 1, 2, 3, 4 or 5 points.

• STALE scores 15 points
• CHEAT scores 15 points
• CHEST scores 19 points
• CHASE scores 16 points

My tablet computer can fit 20 apps on the screen. When I hold the tablet in a landscape orientation there are five apps going across and four going downwards. When I rotate the tablet so it is portrait there are four apps going across and five going downwards. The icons then shuffle themselves so they are in the same order, reading from the top left of the screen. Which two icons stay in the same spot on the screen?Deselect Answer

There are four cards, all of which have a number on one side and a colour on the other side. They are placed on the table like this:

Which cards do you need to turn over to check whether the following statement is true?
'If there is an even number on one side of the card then the other side is red.'Deselect Answer

Marco Polo, Venetian traveller, travelled from Venice to China and Japan inDeselect Answer

The world’s oldest continuously inhabited city is 

The island of Corsica is associated with

Marx belonged toDeselect Answer

Napoleon got finally overthrown in the Battle of Waterloo in the yearDeselect Answer

The Declaration of the Rights of Man is related withDeselect Answer

Which U.S. President announced the “New Deal” for economic recovery in the aftermath of the Great Depression?

From which language, has the term ‘democracy’ been derived?

The world’s first drainage system was build by the people ofDeselect Answer

‘Liberty, Equality and Fraternity’ is the call associated withDeselect Answer

Hitler became the Chancellor of Germany inDeselect Answer

Which decade is called as the “Era of Decolonisation”?

If these solid bodies have the same base area, which other feature do they have in common?
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Consider the following roof top views, characterized by horizontal eaves lines. Determine the only one where NOT EVERY roof pitch have the same slope.
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Consider the plants of a building and their orientation. Associate to each elevation view shown below the correct orientation with respect to the cardinal points.

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Of the perspective views shown below, which one is coherent with the orthographic projection?




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Given the front and right views of a solid, what is its correct three-dimensional representation?
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Which of the following solid figures from 1 to 5 completes the solid (U) in such a way to obtain a cube regular?
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Solve the equation
(log)₂ (x-3)+(log)₂ (x-2)=1
for x.Deselect Answer

If 2x + 3 as a divisior of 2x³ + 7x² + 8x + c with a remainder of 0, c isDeselect Answer

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What must be the value of k if the lines 3x - y = 9 and kx + 3y= 5 are to be perpendicular?Deselect Answer

A 15kg wagon is pulled to the rigth with a force of  45 mewtons. The wagon accelerates at 2 meters per second squared. What is the net (unbalanced) force accelerating the wagon?Deselect Answer

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Two small objects of masses M₁ and M₂ are suspended from massless, unstretchable strings. of equal length. The object with mass M₁ is raised through a height h as shown above and released. If the objects stick together after colliding, they will swing on the other side to a height that isDeselect Answer

A rock weighing 10 newtons is lifted a distance d from the ground. The work done by the force that lifts the rock is 10 joules. The rock is then dropped on a wooden stake, thus driving the stake into the ground.
The distance d is most nearlyDeselect Answer