Life originated in the early seas less than a billion years after Earth was formed.
Yet another three billion years were to pass before the first
plants and animals appeared
on the continents. Life's transition from the sea to the land was
perhaps as much of an
Line evolutionary challenge as was the genesis of life.
(5) What forms of life were able to
make such a drastic change in lifestyle ? The
traditional view of the first terrestrial organisms is based on
megafossils ― relatively
large specimens of essentially whole plants and animals. Vascular
plants, related to
modern seed plants and ferns, left the first comprehensive
megafossil record. Because
of this, it has been commonly assumed that the sequence of
terrestrialization reflected
(10) the evolution of modern terrestrial ecosystems. In this view,
primitive vascular plants
first colonized the margins of continental waters, followed by
animals that fed on the
plants, and lastly by animals that preyed on the plant-eaters.
Moreover, the megafossils
suggest that terrestrial life appeared and diversified explosively
near the boundary
between the Silurian and the Devonian periods, a little more than
400 million
(15) years ago.
Recently, however,
paleontologists have been taking a closer look at the sediments
below this Silurian-Devonian geological boundary. It turns out
that some fossils can be
extracted from these sediments by putting the rocks in an acid
bath.The technique has
uncovered new evidence from sediments that were deposited near the
shores of the
(20) ancient oceans ― plant microfossils and
microscopic pieces of small animals. In many
instances the specimens are less than one-tenth of a millimeter in
diameter. Although
they were entombed in the rocks for hundreds of millions of years,
many of the fossils
consist of the organic remains of the organism.
These newly discovered fossils
have not only revealed the existence of previously
(25) unknown organisms, but have also pushed back these dates for the invasion of
land by multicellular organisms. Our views about the nature of the early plant and
animal communities are now being revised. And with those revisions come new
speculations about the first terrestrial life-forms.
Questions
28. The word “drastic” in line 5 is closest
in meaning to
(A) widespread
(B) radical
(C) progressive
(D) risky
29. According to the theory that the author calls “the traditional
view,” what was the
first form of life to appear on
land?
(A)
Bacteria
(B) Meat-eating animals
(C) Plant-eating animals
(D) Vascular plants
30. According to the passage, what happened about 400 million
years ago?
(A) Many terrestrial life-forms
died out.
(B) New life-forms on land
developed at a rapid rate.
(C) The megafossils were
destroyed by floods.
(D) Life began to develop in
the ancient seas.
31. The word “extracted” in line 18 is closest in meaning to
(A) located
(B) preserved
(C) removed
(D) studied
32. What can be inferred from the passage about the fossils
mentioned in lines 17-20 ?
(A) They have not been helpful
in understanding the evolution of terrestrial life.
(B) They were found in
approximately the same numbers as vascular plant fossils.
(C) They are older than the
megafossils.
(D) They consist of modern
life-forms.
33. The word “instances” in line 21 is closest in meaning to
(A) methods
(B) processes
(C) cases
(D) reasons
34. The word “they” in line 22 refers to
(A) rocks
(B) shores
(C) oceans
(D) specimens
35. The word “entombed” in lime 22 is closest in meaning to
(A) crushed
(B) trapped
(C) produced
(D) excavated
36. Which of the following resulted from the discovery of
microscopic fossils?
(A) The time estimate for the
first appearance of terrestrial life-forms was revised.
(B) Old techniques for
analyzing fossils were found to have new uses.
(C) The origins of primitive
sea life were explained.
(D) Assumptions about the
locations of ancient seas were changed.
37. With which of the following conclusions would the author
probably agree?
(A) The evolution of
terrestrial life was as complicated as the origin of
life itself.
(B) The discovery of
microfossils supports the traditional view of how terrestrial
life evolved.
(C) New species have appeared
at the same rate over the course of the last
400 million years.
(D) The technology used by
paleontologists is too primitive to make accurate
determinations about ages of fossils.
Answers Please tally your answer with the below provided
answers and then comment here how much you got!
28. B 29. D 30. B 31. C 32. C 33. C 34. D 35. B 36. A 37. A
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