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【单选题】
Disaster struck 250 million years ago, when the worst devastation in the earth's history occurred. Called the end-Permian mass extinction, it marks a fundamental change in the development of life. The history of life on the earth is replete with catastrophes of varying magnitudes. The one that has captured the most attention is the extinction of the dinosaurs and other organisms 65 million years ago—between the Cretaceous and Tertiary periods—which claimed up to half of all species. As severe as that devastation was, it pales in comparison to the greatest disaster of them all: the mass extinction some 250 million years ago, at the end of the Permian period. Affectionately called 'the mother of mass extinctions' among paleontologists (with apologies to Saddam Hussein), it yielded a death toll that is truly staggering. About 90 percent of all species in the oceans disappeared during the last several million years of the Permian. On land, more than two thirds of reptile and amphibian families vanished. Insects, too, did not escape the carnage: 30 percent of insect orders ceased to exist, marking the only mass extinction insects have ever undergone. But from catastrophes, opportunities arise. For several hundred million years before the end-Permian event, the shallow seas had been dominated by life-forms that were primarily immobile. Most marine animals lay on the seafloor or were attached to it by stalks, filtering the water for food or waiting for prey. In the aftermath of the extinction, many once minor groups-active, predatory relatives of modern-day fish, squids, snails and crabs—were able to expand. Some completely new lineages appeared. This ecological reorganization was so dramatic that it forms a fundamental boundary in the history of life. Not only does it demarcate the Permian and Triassic periods, it also establishes the close of the Paleozoic era and the start of the Mesozoic era. The modern tidal pool reflects what lived and what died 250 million years ago. Over the past few years, exciting new insights into the causes and consequences of the end-Permian mass extinction have poured in from virtually every branch of the earth sciences. Some of these findings include detailed studies of rapid changes in ocean chemistry, more thorough documentation of extinction patterns and new analyses showing that large volcanic eruptions occurred at the Permo Triassic boundary. How much do mass extinctions contribute to the evolution of a group as compared with long-term adaptive trends? For examples sea urchins are ubiquitous in modern oceans but were relatively uncommon during the Permian. Only a single genus, Miocidaris, is known for certain to have survived the extinction. Did Miocidaris survive by pure chance, or was it better adapted? Would sea urchins today look any different had it not been for the end Permian extinction? To resolve such questions, we need to learn more about the causes of the catastrophe and how those species that survived differed from those that disappeared. The key sources for this information are rock layers and fossils. Unfortunately, samples from the late Permian and early Triassic are notoriously difficult to come by. The fossil record across the boundary is plagued by poor preservation, a lack of rock to sample and other problems, including access. An extensive drop in sea level during the late Permian limited the number of marine rocks deposited on land, and many areas where the best rocks were preserved (most notably, in southern China) have been relatively hard for some geologists to reach. As such, it has proved difficult to ascertain just how quickly life was snuffed out or if the deaths were subject to any regional variations. Some creatures, especially those sensitive to changes in the environment, died off rapidly, as shown by Erik Flugel and his colleagues at the University of Erlangen, who arrive
A.
two thirds
B.
half
C.
90%
D.
30%
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【单选题】患者,男,68岁。因慢性阻塞性肺部疾病,肺部感染入院,经吸氧、抗炎、祛痰、平喘等治疗后,患者近日出院,护士对其进行腹式呼吸的指导,不正确的是
A.
用鼻吸气,口呼气
B.
吸气时腹部鼓起,呼气时腹部下陷
C.
呼与吸时间比2:1-3:1
D.
每次30分钟
E.
深而慢的呼吸模式
【判断题】由欧氏几何知识可知:空间中直线有方向向量(平行公理),没有法向量;平面没有方向向量,有法向量
A.
正确
B.
错误
【单选题】患者男性,68岁,因\"慢性阻塞性肺疾病,肺部感染\"收入院,经吸氧、抗炎、祛痰平喘
A.
患者男性,68岁,因/"慢性阻塞性肺疾病,肺部感染/"收入院,经吸氧、抗炎、祛痰平喘等治疗后,患者近日出院,护士对其进行腹式呼吸指导不正确的是( ) A.用鼻吸气,口呼气
B.
吸气时腹部鼓起,呼气时腹部下陷
C.
呼与吸时间比为2:1~3:1
D.
每次30分钟
E.
深而慢的呼吸模式
【单选题】89书法家颜真卿的楷书代表作是( )
A.
《神策军碑》
B.
《兰亭集序》
C.
《玄秘塔碑》
D.
《麻姑仙坛记》
【单选题】目前最具潜力的国际工程承包市场是()
A.
北美市场
B.
亚太市场
C.
中东市场
D.
非洲市场
【单选题】关于三叉神经脊柬和脊束核的错误描述 ( )
A.
管理头面部痛温觉
B.
位于脑桥和延髓内
C.
三叉神经脊束核住于三叉神经脊束的外侧
D.
三叉神经脊束为第一级神经元的中枢突
E.
三叉神经脊束核下端与脊髓胶状质延续
【单选题】关于三叉神经脊束和脊束核的叙述,错误的是
A.
位于脑桥和延髓内
B.
三叉神经脊束核位于三叉神经脊束的外侧
C.
三叉神经脊束核下端与脊髓的胶状质延续
D.
三叉神经脊束为第一级神经元的中枢突组成
E.
传导面部皮肤的痛、温觉
【简答题】材料出库单无法记账,可能是什么原因?
【多选题】三叉神经脊束核()
A.
发出纤维在同侧上行组成三叉丘系
B.
与痛、温觉传导有关
C.
向下与脊髓胶状质相续
D.
接受三叉神经节细胞中枢突
E.
位于三叉神经脊束内侧
【单选题】关于三叉神经脊束和脊束核的错误描述为()
A.
三叉神经脊束为第一级神经元的中枢突
B.
三叉神经脊束核位于三叉神经脊束的外侧
C.
管理面部皮肤痛、温觉
D.
位于脑桥和延髓内
E.
三叉神经脊束核下端与脊髓的胶状质延续
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