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3. GWD-1-Q25 to Q28生理因素和环境因素对硅藻生物钟产生的影响
Recently biologists have been 近期生物家对HV硅藻的与潮汐关联的周期
interested in a tide-associated 行为感兴趣。这种藻是显微可见的金棕色
periodic behavior displayed by 藻,栖于潮水冲刷的海岸线(潮间带)。
Line the diatom Hantzschia virgata, a
(5) microscopic golden-brown alga that
inhabits that portion of a shoreline
washed by tides (the intertidal zone).
Diatoms of this species, sometimes 被称为“通勤者”的硅藻高潮挖坑,日间低
called “commuter” diatoms, remain 潮时出洞。
(10) burrowed in the sand during high
tide, and emerge on the sand sur-
face during the daytime low tide.
Just before the sand is inundated by 在潮水上升淹没沙前它又再挖洞。
the rising tide, the diatoms burrow
(15) again. Some scientists hypothesize 一些科学家假设通勤者知道低潮,因为它
that commuter diatoms know that it 感知环境变化,如潮汐运动导致的温度改
is low tide because they sense an 变或压力变化。
environmental change, such as an
alteration in temperature or a change
(20) in pressure caused by tidal move-
ment. However, when diatoms are 但是,当硅藻在实验室稳定环境下,在数
observed under constant conditions 周内仍表现周期行为,继续挖洞。
in a laboratory, they still display
periodic behavior, continuing to bur-
(25) row on schedule for several weeks.
This indicates that commuter diatoms, 这表明硅藻并非依赖环境信号来定时间,
rather than relying on environmental 而是拥有一个内在的生物钟,让它预计环
cues to keep time, possess an inter- 境的周期变化。
nal pacemaker or biological clock
(30) that enables them to anticipate peri-
odic changes in the environment.
A commuter diatom has an unusu- 残酷环境压力造就了硅藻异常准确的生
ally accurate biological clock, a 物钟;
consequence of the unrelenting
(35) environmental pressures to which
it is subjected; any diatoms that do 未在潮到前挖洞的硅藻会被冲走。
not burrow before the tide arrives
are washed away.提出现象及其研究
This is not to suggest that the 这并不是说生物钟周期一成不变。
(40) period of this biological clock is
immutably fixed. Biologists have 生物家指出,虽然硅藻不靠环境定时间,
concluded that even though a 环境因素- 包括潮水流体静力压力、盐度
diatom does not rely on the envi- 和机械刺激及温度- 能让硅藻按照潮汐
ronment to keep time, environmental 周期改变生物钟周期。
(45) factors—including changes in the
tide’s hydrostatic pressure, salin-
ity, mechanical agitation, and
temperature—can alter the period
of its biological clock according to
(50) changes in the tidal cycle. In short, 简而言之,机体生物钟与环境的关系就
the relation between an organism’s 像腕表和它主人的关系。
biological clock and its environment
is similar to that between a wristwatch
and its owner: the owner cannot 主人不能让表走快或走慢,但可以重置
(55) make the watch run faster or slower, 指针。
but can reset the hands. However, 但是这种关系在高低潮线间居民如通
this relation is complicated in intertidal 勤者硅藻中是复杂的,因为这些机体
dwellers such as commuter diatoms 受到太阳日周期和潮汐周期等的影响,
by the fact that these organisms are 有时在单独行为中同时表现两种周期。
(60) exposed to the solar-day cycle as
well as to the tidal cycle, and some-
times display both solar-day and
tidal periods in a single behavior.
Commuter diatoms, for example, 例如通勤者只在日间低潮时出现。
(65) emerge only during those low tides
that occur during the day.环境因素对其生物钟的影响
现象解释
逻辑简图:
1P: recently biologist interested in T behavior of HV. Some hypothesis… however… indicate, rather than, possess..
2P: not suggest fix. Biologist conclude environmental factors can alter
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GWD-1-Q25:
The passage suggests which of the following about the accuracy of the commuter diatom’s biological clock?
A. The accuracy of the commuter diatom’s biological clock varies according to changes in the tidal cycle.反
B. The unusual accuracy that characterizes the commuter diatom’s biological clock is rare among intertidal species.
C. The commuter diatom’s biological clock is likely to be more accurate than the biological clock of a species that is subject to less intense environmental pressures.定位32-36
D. The commuter diatom’s biological clock tends to be more accurate than the biological clocks of most other species because of the consistency of the tidal cycle.
E. The accuracy of the commuter diatom’s biological clock tends to fluctuate when the diatom is observed under variable laboratory conditions.
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GWD-1-Q26:
The author of the passage compares the relationship between an organism’s biological clock and its environment to the relation between a wristwatch and its owner most probably in order to
A. point out a fundamental difference between the function of biological clocks in organisms and the use of mechanical clocks by humans
B. illustrate the way in which the period of an organism’s biological clock can be altered by environmental factors
C. suggest that there are important similarities between the biological clock in organisms such as the commuter diatom and the biological clock in humans
D. support an argument regarding the methods used by certain organisms to counteract the influence of the environment on their biological clocks
E. question the accuracy of the biological clock in organisms such as the commuter diatom
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GWD-1-Q27:
According to the passage, the periodic behavior displayed by commuter diatoms under constant laboratory conditions is characterized by which of the following?
A. Greater unpredictability than the corresponding behavior under natural conditions
B. A consistent periodic schedule in the short term定位第一段 39-41
C. No difference over the long term from the corresponding behavior under natural conditions
D. Initial variability caused by the constant conditions of the laboratory
E. Greater sensitivity to environmental factors than is the case under natural conditions
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GWD-1-Q28:
The primary purpose of the passage is to
A. dispute the influence of environmental factors on the tide-associated behavioral rhythms displayed by the diatom Hantzschia virgata
B. describe how certain tide-associated behavioral rhythms displayed by the diatom Hantzschia virgata have changed over time
C. compare tide-associated behavioral rhythms to solar-day behavioral rhythms in the diatom Hantzschia virgata
D. examine how certain biological and environmental influences affect the tide-associated behavioral rhythms displayed by the diatom Hantzschia virgata
E. identify certain environmental factors that limit the effectiveness of the biological clock in the diatom Hantzschia virgata
注意文章的进展,前面说了HV所表现的现象,后面说环境因素对其生物钟的影响
GWD18-Q23
Which of the following can be inferred from the passage about the effect of the solar-day cycle on the tide-associated periodic behavior displayed by commuter diatoms?
A. The solar-day cycle makes this behavior less advantageous to the commuter diatoms at certain times of the year.
B. The solar-day cycle makes this behavior somewhat more erratic.
C. The solar-day cycle makes this behavior less important to the survival of the commuter diatoms.
D. Because of the solar-day cycle, this behavior is forced to proceed at a more rapid pace at certain times during the 24-hour day.
E. Because of the solar-day cycle, this behavior is not expressed at certain times during the 24-hour day.
Q25:
According to the passage, each of the following is characteristic of the tide-associated periodic behavior of commuter diatoms EXCEPT:
A. It is triggered when the diatoms are inundated by the tide.
B. It is correlated with the rise and fall of the tide.
C. It adjusts to changes in the tidal cycle.
D. It is influenced by the solar-day cycle.
E. It is regulated by an innate time-keeping mechanism. |
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