LIFE ON EARTH ... BUT NOT AS WE KNOW IT

“Never mind aliens in outer space. Some scientists believe we may be sharing the planet with ‘weird’ life forms that are so different from our own that they are invisible to us”

By: Robin McKie

Published: The Observer, Sunday 14 April 2013; www.observer.co.uk or www.guardian.co.uk

Level of Difficulty: ** Note to the student: this a difficult level **so do it after you have done the others in the file.

BEFORE YOU READ

• Do you believe there are other life forms in space or on our planet?
• Do you believe all life forms have the same biological make up as our own?
• Do you believe there may be such life forms on earth?

QUESTIONS

1. What does “They” refer to in the phrase “They can make the desert glitter”?
2. Prof. Carol Cleland doesn’t share the accepted explanations that desert varnish…………………………………………………………………………………………………………
3. What does “It” refer to in the phrase “It is a striking idea…”? The fact that………………………………………………………………………………………………………………
4. What is the possible implication of the shadow biosphere theory for space research?
5. The existence of the shadow biosphere would also mean that we would have to reconsider…………………………………………………………………………………………………………
6. What does “This point” in the sentence “This point is stressed by the US biologist Craig Venter refer to? The fact that we are going to have trouble …………………………………………
7. What scientific fact makes the creation of life forms with a very different biochemistry to our own perfectly feasible?
8. Our failure to discover weird life is mainly due to tunnel vision because …………………………………
9. Dimitar Sasselov feels he has found a possible clue to the existence of the shadow biosphere. It is the fact that  …………………………………………………………………………………………………………………….
10. It is widely believed that the shadow biosphere would be carbon based because …………………
11. Read the paragraph beginning “Billions of years ago” and complete the following sentence to form the main idea: Just because life forma on earth are based on DNA and on proteins made from 20 amino acids doesn’t mean ………………………………………………………………………………
12. Weird life could be discovered in extreme environments via …………………………………………………

TRUE, FALSE OR DON’T KNOW?

Test your comprehension of the text: decide which of the above categories the following sentences fall into according to the information in the text without referring back. When you have decided, look back at the text to see if you were right.

1. The deposits of weird life form desert sheen.
2. Right handed life forms could be led to reveal themselves via honey traps
3. Weird life is made up of right handed amino acids.
4. We are incapable of discovering weird life forms with current methods.
5. The microbial life forms termed the shadow biosphere have a completely different biosphere.
6. Bacteria have not thus far produced desert sheen.
7. All researchers support the view that chemical reactions and ecological processes produce desert varnish

     WRITING TASK

 Write a brief summary of the text to print on the back page of a popular daily. Remember, you have limited space.

LIFE ON EARTH… BUT NOT AS WE KNOW IT KEY AND TEACHER’S NOTES

This fascinating science text is guaranteed to tickle the fancy of even the most adamant opponents of science. I have added some true false questions along the lines of IELTS for variation. Another plus is that this text lends itself to summary practice because it is so easy to weed out the actual facts and write a short but concise summary.

1. These layers of manganese, arsenic and silica (known as desert varnish). Careful! There is no “are” in the answer.
2. Is produced by chemical reactions that act over thousands of years or by ecological processes yet to be determined.
3. We may be co-inhabiting with microbial life forms that have a completely different biochemistry from the one shared by life as we currently know it.
4. Its existence would greatly boost expectations of finding life elsewhere in the cosmos.
5. The way we hunt for life on other worlds.
6. Detecting alien entities if the mass laboratories of modern science have not yet spotted them on our planet.
7. The fact that there are up to a hundred amino acids in nature
8. The methods that we use to detect micro organisms are based entirely on our own biochemistry. This is the minimum required. If you add the rest it is not wrong but it is unnecessary.
9. There is slightly too much carbon dioxide in the atmosphere than can be explained by the emissions of standard life forms on earth.
10. Carbon can create a vast range of organic materials.
11. Life forms based on different bases and proteins don’t exist.
12. Microscopic studies.

TRUE, FALSE OR DON’T KNOW KEY

1. Don’t know
2. True
3. Don’t know
4. True
5. Don’t know
6. True
7. False

Remember there is a lot of conjecture in the text!