进化概要 -- -- 高级

How can one bird supply so much information?
::一只鸟怎么能提供这么多信息?

By its beak . This is a Galápagos finch, one of the studied by Charles Darwin . This and all the other finch species of the Galápagos Islands provided Darwin with valuable evidence for his theory .
::这是查尔斯·达尔文研究过的Galápagos Finch。这个以及加拉帕戈斯群岛所有其他的芬奇物种都为达尔文的理论提供了宝贵的证据。

Evolution: A Summary
::进 程: 简 述

Altogether, the , homologies, analogies, vestigial structures , molecular uniformity and diversity, and provide powerful scientific evidence for the descent of today’s species from common ancestors . Some details of have been and are still being modified. However, the remarkable biological discoveries of the 150 years since Darwin published On the have dramatically strengthened support for his theory. Moreover, Darwin’s theory continues to enlighten new discoveries. Prominent geneticist and evolutionary biologist Theodosius Dobzhansky said, "Nothing in biology makes sense except in the light of evolution." Perhaps we could paraphrase Dobzhansky: Everything in biology makes sense in the light of evolution.
::总而言之,人类学、类比、遗迹结构、分子统一性和多样性,为当今物种从共同祖先的祖先中消失提供了有力的科学证据。 一些细节已经并仍在修改中。 然而,自达尔文发表《关于达尔文》的150年来的非凡生物发现极大地加强了对其理论的支持。 此外,达尔文的理论继续启发新的发现。 著名遗传学家和进化生物学学家Theodosius Dobzhansky说 , “ 生物学中除了进化外,没有任何东西是有意义的。 ”也许我们可以引用Dobzhansky的话:从进化角度看,生物学中的一切都有意义。

At that time, the only piece still missing from the evidence puzzle is direct observation of the process itself. Darwin thought that humans could never witness evolution in action because of the vast time periods required. For once, however, he was mistaken; evolution in action can and has been observed.
::当时,证据拼图中唯一缺少的一块是直接观察过程本身。 达尔文认为人类永远无法看到行动演变,因为需要很长的时间。 然而,他有一次被误解了;行动演变可以并且已经被观察到了。

Evolution Continues and We “Catch it in the Act”
::进化在继续,我们“在法案中抓住它”

Much more passively and with a clear understanding of our lack of control, humans have watched rapidly evolve through to cause frightening worldwide epidemics , or pandemics - including the 1918 “Spanish flu”, Severe Acute Respiratory Syndrome (SARS), West Nile virus, the “avian flu” (caused by a highly pathogenic viral subtype of influenza A, known as H5N1), and the 2009 "swine flu" (caused by the H1N1 influenza virus). The Figure  shows the increase in human infections and deaths from H5N1. Mutations have adapted it for life in both birds and humans and for transmission from bird to bird and bird to human. If a future mutation adapts it for effective transmission from human to human, a serious epidemic could result. If, as some argue, influenza pandemics occur in cycles, we are overdue for a dramatic demonstration of evolution and natural selection.
::人类更加被动地、更清楚地了解我们缺乏控制,目睹了人类迅速演变,导致可怕的世界流行病或流行病,包括1918年的“西班牙流感”、严重急性呼吸系统综合症(萨斯)、西尼罗病毒、“禽流感”(由H5N1)和2009年的“猪流感”(由H1N1流感病毒造成),该图显示人类感染和H5N1流感死亡的上升情况。 变异使其适应鸟类和人类的生活,适应鸟类和鸟类向人类的传播。如果未来的突变使其适应人类的有效传播,则可能产生严重的流行病。 如果有人认为流感是周期性地发生,我们早就应该对进化和自然选择作出重大示范。

The Peppered Moth
::胡椒麻疯

Peppered moths ( Figure  ) are mostly white with black specks; this color pattern hid them for centuries from predatory birds, as the moths rest against lichen covered tree trunks. However, soot from the Industrial Revolution darkened the trees and destroyed their camouflage, selecting instead for the dark mutants that occasionally appeared. Gradually the shifted to the dark color, an instance of natural selection that was directly observed by Englishmen of the time. Subsequent improvements in control have cleaned up the environment, and the English now note a new change: the trees have lightened, and moth populations are returning to their original coloration. These direct observations of natural selection would have delighted Darwin (except perhaps for the pollution) just a few years earlier.
::胡椒飞蛾(Figure ) 大多是白色的,有黑色斑点;这种颜色模式在几个世纪内将飞蛾隐藏在掠食性鸟类身上,因为飞蛾停靠在地衣覆盖的树干上。然而,工业革命的烟雾使树木黑暗化,摧毁了它们的伪装,为偶尔出现的暗色变异者选择了。逐渐转向暗色,这是当时英国人直接观察到的自然选择的例子。随后的自然选择过程清洁了环境,而现在的英国人注意到一种新的变化:树木已经亮亮,蛾类种群正在恢复到原始的颜色。 这些对自然选择的直接观察(也许除了污染之外)在几年前会让达尔文(达尔文)高兴。

The Galápagos Finches
::加拉帕戈斯芬奇

Much more intentionally, biologists Peter and Rosemary Grant (introduced in the Evolution: Biogeography (Advanced) concept) have devoted more than 30 years to a study of two species of Darwin’s finches on one of the Galápagos islands ( Figure  ). Catching, weighing, and recording the seed species eaten by hundreds of these birds, they have witnessed changes in beak size which clearly correlate with changes in weather and availability of food . A severe drought and food shortage in 1977 led to a significant change. Birds whose small beaks could not crack the tough remaining seeds died, and the larger-beaked individuals who survived reproduced. The following year, offspring were larger bodied and larger-beaked, showing that natural selection led to evolution. A rainy winter in 1984-1985 reversed the trend; more soft seeds were produced, and the smaller beaked finches survived to reproduce in greater numbers than their large-beaked cousins. 
::更有意的是,生物学家彼得和罗斯玛丽·格兰特(在进化:生物地理学(Advanced)概念中引入的生物学家彼得和罗斯玛丽·格兰特(Rosemary Grant)用30多年时间研究了加拉帕戈斯岛之一(Fitare ) , 研究了达尔文的两只雀斑。 捕捉、称重和记录上百头鸟吃掉的种子品种,它们目睹了山雀大小的变化,这与天气和粮食供应的变化明显相关。 1977年的严重干旱和粮食短缺导致了显著的变化。 其小嘴无法破碎残存的种子的鸟类,以及存活下来的较大型的鸟类。 第二年,后代规模更大,表明自然选择导致了进化。 1984-1985年的雨季扭转了这一趋势;生产了更多的软种子,而较小的小嘴鳍存活下来,其繁殖数量大于其大嘴的表表兄弟。

Jonathan Winter eloquently describes the Grants’ work and discoveries in his Pulitzer Prize-winning The Beak of the Finch, A story of Evolution in our Time. His words urge us to see evolution as ongoing for all life, making a fitting conclusion to this lesson and chapter:
::乔纳森·温特雄辩地描述了该赠款在其获得普利策奖的“芬奇之嘴 ” ( The Beak of the Finch)中的工作和发现。 “芬奇之嘴 ” ( The Bek of the Finch)是当今时代进化的故事。 他的话敦促我们将进化视为整个生命的持续过程,并恰当地总结了这一教训和章节:

“For all species, including our own, the true figure of life is a perching bird , a passerine, alert and nervous in every part, ready to dart off in an instant. Life is always poised for flight . From a distance it looks still, silhouetted against the bright sky or the dark ground; but up close it is flitting this way and that, as if displaying to the world at every moment its perpetual readiness to take off in any of a thousand directions.” — The Beak of the Finch: A Story of Evolution in Our Time, Jonathan Weiner, 1995.
::“对于所有物种,包括我们自己的物种,生命的真正图象是一只垂死鸟、一只过敏鸟、一只警钟和神经,每部分都准备在一瞬间飞走,生命总是准备飞走,从远处看,它静静地对着明亮的天空或黑暗的地面漂浮着;但近近距离,它正在这样飞动,仿佛它每时每刻都向世界展示它永远愿意向任何一千个方向飞去的准备。”

Summary
::摘要

播放段落
• Viral epidemics occur when chance viral mutations adapt the virus to new hosts or new methods of transmission.
  ::当偶然的病毒突变使病毒适应新的宿主或新的传播方法时,就会出现病毒性传染病。
播放段落
• Peppered moth populations changed color as the Industrial revolution changed the color of their habitat.
  ::随着工业革命改变其栖息地的颜色, 飞蛾聚变了颜色。
播放段落
• Peter and Rosemary Grant studied two closely related species of Darwin’s finches and recorded changes in beak size and body size, which paralleled changes in weather.
  ::彼得和罗斯玛丽·格兰特研究了两个密切相关的达尔文鳍物种,并记录了海嘴大小和体积的变化,这些变化与天气的变化平行。

Review
::回顾

播放段落
1. In what way do viral epidemics demonstrate evolution?
   ::病毒流行病以何种方式显示演变?
播放段落
2. Describe the findings of Peter and Rosemary Grant.
   ::描述彼得和罗斯玛丽·格兰特的调查结果。