ANSWER KEY> Will We Know Alien Life When We See It?
by Tina Hesman Saey 2017
1. RI.2
PART A: Which statement best expresses the central idea of the text?
Astrobiologists know that life exists on other planets, but they don’t think that we will ever
be able to recognize or study it.
While astrobiologists suspect that there may be alien life on other planets, they
believe it might exist or develop in a way that is unfamiliar to us.
In order to identify and study life on other planets, scientists must better understand the
strange life hiding on our own planet first.
Astrobiologists’ definition of living and nonliving things are too vague and need to be
made more specific before they can identify living things on other planets.
2. RI.1
PART B: Which detail from the text best supports the answer to Part A?
“But recognizing life on different worlds isn’t likely to be this simple. It could prove
especially hard if the recipe for life elsewhere does not include familiar
ingredients.” (Paragraph 3)
“Many insist that certain features must be present for any type of life, including aliens.
These include an active metabolism, reproduction and evolution.” (Paragraph 7)
“In recent years, more than 1,000 planets have been spotted outside our solar system.
With their discovery, the odds favoring the existence of alien life are better than ever.”
(Paragraph 14)
“‘We have an assumption that life on Earth has a pace,’ she says. Some shadow life may
instead grow far more leisurely.” (Paragraph 26)
3. RI.5
How does the author’s discussion of Star Trek contribute to the development of ideas in the text
(Paragraphs 1-2)?
It provides readers with an example of an unfamiliar way that an organism likely exists on
another planet.
It provides a fictional example in which life was not initially identified as alive on
another planet because of its form.
It shows readers how the idea that life exists in a different form on other planets has been
popular for a while.
It proves that there is likely life on other planets that we have come in contact with but did
not recognize as alive.
4. RI.6
What is the author’s main purpose in the text?
to reassure readers that life on other planets exists, even if we can’t see it
to criticizes how astrobiologists’ definition of life is too focused on Earth-life
to explain to readers why life on other planets may be difficult for scientists to
recognize
to describe how life on other planets would be able to survive in different conditions
5. RI.3
What is the relationship between scientists’ definition of life and their ability to identify it on other
planets? Use details from the text in your response.
Answers will vary; students should discuss how scientists’ definition of life guides
them in their search for life, and can limit what they consider to be alive. The author
discusses some of the criteria used to identify something as alive, such as “active
metabolism, reproduction and evolution” and “the requirement that life must have
cells big enough to contain protein-building machines called ribosomes
(RY-boh-soams)” (Paragraph 7). However, some scientists believe that the criteria are
too limiting, and may exclude things that should be considered alive. For instance,
some scientists argue whether or not viruses are alive, stating, “viruses aren’t alive
because they rely on their host cells to reproduce” (Paragraph 9). While establishing
criteria for life might help scientists better make sense of other planets and the
potential life that inhabits it, this criteria could also give them “tunnel vision”
(Paragraph 8). In all, how scientists define life plays an important role in shaping their
views and ability to identify alien life at all.
Explanation:
