2015年9月17日
托福阅读真题第一篇
题材划分： 历史发展史
主要内容： 讲史前人类的生活，先讲通过植物和动物的残余来判断diet。骨头里面不同化学物质的成分，还有人的牙齿的磨损也是证据。后来又讲一些shelter由不同材料不同size。还讲wood和另一种富含fat的东西作为fuel。
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TPO-5 The Origin of the Pacific Island People
TPO-7 Agriculture, Iron, and the Bantu Peoples
TPO-9 Colonizing the Americas via the Northwest Coast
相关背景知识：
"Paleolithic" means "Old Stone Age," and begins with the first use of stone tools. The Paleolithic is the earliest period of the Stone Age.
The early part of the Paleolithic is called the Lower Paleolithic, which predates Homo sapiens, beginning with Homo habilis (and related species) and with the earliest stone tools, dated to around 2.5 million years ago.Early Homo sapiens originated some 200,000 years ago, ushering in the Middle Paleolithic. Anatomic changes indicating modern language capacity also arise during the Middle Paleolithic.The systematic burial of the dead, music, early art, and the use of increasingly sophisticated multi-part tools are highlights of the Middle Paleolithic.
Throughout the Paleolithic, humans generally lived as nomadic hunter-gatherers. Hunter-gatherer societies tended to be very small and egalitarian, though hunter-gatherer societies with abundant resources or advanced food-storage techniques sometimes developed sedentary lifestyles with complex social structures such as chiefdoms, and social stratification. Long-distance contacts may have been established, as in the case of Indigenous Australian "highways."
题材划分： 生态环境
主要内容： 讲影响季节的三种因素，分别是倾角，离太阳的远近和orbit的椭圆形。但这三个因素一直没证据直到1950年有个证据支持了，就引起热议。但后来又有证据与三个因素理论不一致。然后就研究哪个错了。后来发现都是正确的。只是一个告诉了一个地方的气候变化，另一个代表global的气候变化。
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TPO-10 Variations in the Climate
相关知识背景：
Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors such as biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. Certain human activities have also been identified as significant causes of recent climate change, often referred to as "global warming".
Scientists actively work to understand past and future climate by using observations and theoretical models. A climate record—extending deep into the Earth's past—has been assembled, and continues to be built up, based on geological evidence from borehole temperature profiles, cores removed from deep accumulations of ice, floral and faunal records, glacial and periglacial processes, stable-isotope and other analyses of sediment layers, and records of past sea levels. More recent data are provided by the instrumental record. General circulation models, based on the physical sciences, are often used in theoretical approaches to match past climate data, make future projections, and link causes and effects in climate change.
On the broadest scale, the rate at which energy is received from the sun and the rate at which it is lost to space determine the equilibrium temperature and climate of Earth. This energy is distributed around the globe by winds, ocean currents, and other mechanisms to affect the climates of different regions.
Factors that can shape climate are called climate forcings or "forcing mechanisms". These include processes such as variations in solar radiation, variations in the Earth's orbit, variations in the albedo or reflectivity of the continents and oceans, mountain-building and continental drift and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond more slowly in reaction to climate forcings, while others respond more quickly. There are also key threshold factors which when exceeded can produce rapid change.
Forcing mechanisms can be either "internal" or "external". Internal forcing mechanisms are natural processes within the climate system itself (e.g., the thermohaline circulation). External forcing mechanisms can be either natural (e.g., changes in solar output) or anthropogenic (e.g., increased emissions of greenhouse gases).
Whether the initial forcing mechanism is internal or external, the response of the climate system might be fast (e.g., a sudden cooling due to airborne volcanic ash reflecting sunlight), slow (e.g. thermal expansion of warming ocean water), or a combination (e.g., sudden loss of albedo in the arctic ocean as sea ice melts, followed by more gradual thermal expansion of the water). Therefore, the climate system can respond abruptly, but the full response to forcing mechanisms might not be fully developed for centuries or even longer.
题材划分：生物类
主要内容：讲了恐龙被一致认为是水栖动物，因为脖子长而且腿不能支持body。后来发现水下活的话，pressure太大了，它无法呼吸。然后就有人觉得是两栖动物，但发现它的骨头和一般两栖动物不一样。而且它在陆地上有benefits。最后一段说不能很确定是陆地动物，因为这类恐龙的有些品种不能抬高头去吃食物，只能吃长得低的植物，但有些种类的却可以，这还讲了在museum用骨架做电脑模拟。
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OG The Origins of Cetaceans
相关知识背景：
Dinosaurs diverged from their archosaur ancestors during the Middle to Late Triassic period, roughly 20 million years after the Permian–Triassic extinction event wiped out an estimated 95% of all life on Earth. Radiometric dating of the rock formation that contained fossils from the early dinosaur genus Eoraptor at 231.4 million years old establishes its presence in the fossil record at this time. Paleontologists think that Eoraptor resembles the common ancestor of all dinosaurs; if this is true, its traits suggest that the first dinosaurs were small, bipedal predators. The discovery of primitive, dinosaur-like ornithodirans such as Marasuchus and Lagerpeton in Argentinian Middle Triassic strata supports this view; analysis of recovered fossils suggests that these animals were indeed small, bipedal predators. Dinosaurs may have appeared as early as 243 million years ago, as evidenced by remains of the genus Nyasasaurus from that period, though known fossils of these animals are too fragmentary to tell if they are dinosaurs or very close dinosaurian relatives.
When dinosaurs appeared, they were not the dominant terrestrial animals. The terrestrial habitats were occupied by various types of archosauromorphs and therapsids, like cynodonts and rhynchosaurs. Their main competitors were the pseudosuchia, such as aetosaurs, ornithosuchids and rauisuchians, which were more successful than the dinosaurs. Most of these other animals became extinct in the Triassic, in one of two events. First, at about 215 million years ago, variety of basal archosauromorphs, including the protorosaurs, became extinct. This was followed by the Triassic–Jurassic extinction event (about 200 million years ago), that saw the end of most of the other groups of early archosaurs, like aetosaurs, ornithosuchids, phytosaurs, and rauisuchians. Rhynchosaurs and dicynodonts survived (at least in some areas) at least as late as early-mid Norian and early Rhaetian, respectively, and the exact date of their extinction is uncertain. These losses left behind a land fauna of crocodylomorphs, dinosaurs, mammals, pterosaurians, and turtles. The first few lines of early dinosaurs diversified through the Carnian and Norian stages of the Triassic, possibly by occupying the niches of the groups that became extinct.
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