Where Have All the Frogs Gone? In the 1980s, scientists around the world began to notice something strange： Frogs were disappearing. More recent research has shown that many kinds of amphibians （两栖动物）are declining or have become extinct. They have been around for a long time — over350 million years. Why are they dying out now? Scientists are seriously concerned about this question. First of all, amphibians are an important source of scientific and medical knowledge. By studying amphibians, scientists have learned about new substances that could be very useful for treating human diseases.Further research could lead to many more discoveries, but that will be impossible if the amphibians disappear. The most serious aspect of amphibian loss, however, goes beyond the amphibians themselves. Scientists are beginning to think about what amphibian decline means for the planet as a whole. If the earth is becoming unlivable for amphibians, is it also becoming unlivable for other kinds of animals and human beings as well? Scientists now believe that amphibian decline is due to several environmental factors. One of these factors is the destruction of habitat, the natural area where an animal lives. Amphibians are very sensitive to changes in their habitat. If they cannot find the right conditions, they will not lay their eggs. These days, as wild areas are covered with houses, roads, farms, or factories, many kinds of amphibians are no longer laying eggs. For example, the arroyo toad （蟾蜍）of southern California will only lay its eggs on the sandy bottom of a slow-moving stream. There are very few streams left in southern California, and those streams are often muddy because of building projects. Notsurprisingly, the arroyo toad is now in danger of extinction. There are a number of other factors in amphibian decline. Pollution is one of them. In many industrial areas, air pollution has poisoned the rain, which then falls on ponds and kills the frogs and toads that live there. In farming areas, the heavy use of chemicals on crops has also killed off amphibians. Another factor is that air pollution has led to increased levels of ultraviolet (UV) light. This endangers amphibians, which seem to be especially sensitive to UV light. And finally, scientists have discovered a new disease that seems to be killing many species of amphibians in different parts of the world. All these reasons for the disappearance of amphibians are also good reasons for more general concern. The destruction of land, the pollution of the air and the water, the changes in our atmosphere, the spread of diseases — these factors affect human beings, too. Amphibians are especially sensitive to environmental change. Perhaps they are like the canary（金丝雀） bird that coal miners once used to take down into the mines to detect poisonous gases. When the canary became ill or died, the miners knew that dangerous gases were near and their own lives were in danger.Amphibians lay their eggs A in any stream they can find.B in places without UV light,C only on sand.D only in the right conditions.
相关标签： 金丝雀
相关问题推荐
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在进化过程中，鸟嘴形成了各种不同的形状，下图的是鹦鹉、鹭、老鹰和金丝雀头部的花香，从嘴型上看，金丝雀应当是（ ）。
A.
B.
C.
D.
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Where Have All the Frogs Gone? In the 1980s, scientists around the world began to notice something strange： Frogs were disappearing. More recent research has shown that many kinds of amphibians （两栖动物）are declining or have become extinct. They have been around for a long time — over350 million years. Why are they dying out now? Scientists are seriously concerned about this question. First of all, amphibians are an important source of scientific and medical knowledge. By studying amphibians, scientists have learned about new substances that could be very useful for treating human diseases.Further research could lead to many more discoveries, but that will be impossible if the amphibians disappear. The most serious aspect of amphibian loss, however, goes beyond the amphibians themselves. Scientists are beginning to think about what amphibian decline means for the planet as a whole. If the earth is becoming unlivable for amphibians, is it also becoming unlivable for other kinds of animals and human beings as well? Scientists now believe that amphibian decline is due to several environmental factors. One of these factors is the destruction of habitat, the natural area where an animal lives. Amphibians are very sensitive to changes in their habitat. If they cannot find the right conditions, they will not lay their eggs. These days, as wild areas are covered with houses, roads, farms, or factories, many kinds of amphibians are no longer laying eggs. For example, the arroyo toad （蟾蜍）of southern California will only lay its eggs on the sandy bottom of a slow-moving stream. There are very few streams left in southern California, and those streams are often muddy because of building projects. Notsurprisingly, the arroyo toad is now in danger of extinction. There are a number of other factors in amphibian decline. Pollution is one of them. In many industrial areas, air pollution has poisoned the rain, which then falls on ponds and kills the frogs and toads that live there. In farming areas, the heavy use of chemicals on crops has also killed off amphibians. Another factor is that air pollution has led to increased levels of ultraviolet (UV) light. This endangers amphibians, which seem to be especially sensitive to UV light. And finally, scientists have discovered a new disease that seems to be killing many species of amphibians in different parts of the world. All these reasons for the disappearance of amphibians are also good reasons for more general concern. The destruction of land, the pollution of the air and the water, the changes in our atmosphere, the spread of diseases — these factors affect human beings, too. Amphibians are especially sensitive to environmental change. Perhaps they are like the canary（金丝雀） bird that coal miners once used to take down into the mines to detect poisonous gases. When the canary became ill or died, the miners knew that dangerous gases were near and their own lives were in danger.Scientists think that the decline of amphibians could A cause environmental change.B cause a decline in other kinds of animals.C be a warning signal for human beings.D be a good sign for human beings.
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世界上共有鸟9000多种，我国有1186种，占13%；除企鹅、鸵鸟等鸟类不会飞翔以外，绝大多数鸟类几乎都能飞行． 鸟是怎样适应空中飞行生活的？它的哪些结构与飞行相适应呢？请同学们试从如下方面进行探究并论述．（1）鸟飞行的动力器官是什么？__（2）分析如下资料：鸟的食量惊人，蜂鸟一天所吃的食物，约等于体重的2倍．绿头鸭吃进的食物，经消化吸收后形成残渣，0.5小时后就随粪便排出．这则资料说明鸟的消化系统有什么样的特点：__（3）比较鸟与人的心脏大小及心率
心脏
占体重的百分比/%
心搏次数/分
人
0.42
72
鸽
1.71
135-244
金丝雀
1.68
514
蜂鸟
2.37
615该表格说明什么？__
（4）鸟的身体里有发达的气囊．这些气囊一端与肺相通，分布在内脏器官之间，有的还突入到骨的空腔里．分析这则资料鸟类的呼吸系统比起其他动物有什么特点？__（5）在探究鸟适于飞行的特点时，我们用到了哪些探究方法？______．
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下图表示植物不同器官对生长素的反应。请据图回答：
（1)A点所对应的生长素浓度对茎生长的效应是___\_，对芽生长的效应是_______。（2)某生物兴趣小组开展“萘乙酸（生长素类似物）促进某种植物插条生根的最适浓度是多少”的探究实验，按照下表设计浓度梯度（单位：mol/L)：
为了进一步准确地测定最适浓度，应当采取什么改进措施？__\_在农业生产上用萘乙酸溶液浸泡植物插条生根时，除了考虑最适浓度外，还应考虑的因素有________（至少回答两点)。（3)有人发现在植物根的向地性弯曲部位除了生长素的分布不同外，在近地侧同时也集中了大部分的乙烯，由此可知：植物的生长发育过程是_______的结果。（4)在植物的生长发育过程中，达尔文在研究生长素时，将带有尖端的金丝雀虉草的胚芽鞘（A)和除去尖端的金丝雀虉草的胚芽鞘（B)置于单侧光下，结果A弯向光源生长，B不生长也不弯曲，该实验的推论是__\_。植物的向光性对植物叶片生长的意义是________。
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根据所给材料设计活动方案
要求：1.设计应符合语言教育目标和幼儿年龄发展特点;2.任意选择一种活动类型设计相应的活动方案，可提炼“材料2"主题设计谈话活动或听说游戏方案，可围绕“材料2”设计讲述活动、文学作品学习活动或早期阅读;3.活动方案门方案结构完整，包含活动目标、活动准备、活动过程等内容;4.按照活动设计与实施的步骤列出活动过程每一环节的要点.
材料1：中班幼儿语言教育目标
（1)谈话活动：能集中注意力，耐心倾听别人谈话不打断别人的话乐意与同伴交流，能大方地在集体面前说话能说普通话，较连贯地表达自己的意思学会围绕一定的话题谈话，不跑题;学会用轮流的方式谈话，不抢着讲，不乱插嘴继续学习交往语言，提高语言交往能力。
（2)讲述活动：养成先仔细观察，后表达讲述的习惯;逐步学会理解图片和情景中展示的事件顺序;能主动地在集体面前讲述，声音响亮，句式完整;学习按照一定的顺序讲述实物、图片和情景的内容能积极地倾听别人的讲述内容，发现异同，并从中学习好的讲述方法。
（3)听说游戏：在游戏中巩固练习发音，正确运用代词、方位词、副词、动词、连词和介词等能说简单而完整的合成句;能听懂并理解多重游戏规则;学习较迅速地领悟游戏中的语言规则，并能及时作出相应的反应。
（4)文学作品：学习活动喜欢不同形式的文学作品，主动积极地参加文学活动;知道文学作品语言与日常生活语言的不同进一步感受文学作品的语言美;学习理解文学作品的人物形象感受作品的情感基调，能运用较恰当的语言、动作、绘画形式表现自己的理解;能根据文学作品提供的线索，扩展想象，仿编或续编一个情节或一个画面。
（5)早期阅读：能仔细观察图画书画面的人物清节、看懂单页多幅的儿童图画书的内容，增强预知故事情节发展和结局的能力懂得爱护图书，知道图书的构成，有兴趣模仿制作图画书在阅读过程中初步了解汉字的由来和汉字认读的规律，并有主动探索汉字的愿望;喜欢描画图形，尝试用有趣的方式练习汉字的笔画。
材料2：妈妈的最爱
小女孩说：“兔子先生，帮帮忙好吗？我想送妈妈个她喜欢的东西。”
“妈妈喜欢的东西？噢，那一定是个好礼物。”
“妈妈喜欢红色。”小女孩说。
“红色？又不能送‘红色’给你妈妈。”兔子先生沉思着说，“如果是红色的东西呢？比如，红色的小鸟。”
“不行，不行，妈妈喜欢小鸟停在树上。”
“红色的消防车呢？"
“不行，不行，妈妈不会喜欢红色的消防车!"
“那，送草莓好了”
“那个好，妈妈最喜欢草莓了。”
“可是，我还想再送点别的像黄色的东西。”
“恩……金丝雀的黄色的!”兔子先生说
“妈妈喜欢小鸟停在树上。”
“那，奶油是黄色的，妈妈喜欢奶油吗？”
“我们家已经有奶油了。”
“香蕉是黄色的。”
“对了，这个好。妈妈最喜欢香蕉了。”
“可是，我还想送点别的。”
‘你妈妈喜欢什么呢？”
“妈妈喜欢绿色。”
“送翡翠给你妈妈吧!这会是一份很棒的礼物。”
“翡翠太贵，我买不起。”
“豌豆和菠菜呢？豌豆的绿色的，菠菜也是绿色的。”
“不行，我们家晚餐都吃这个。”
“苹果呢？青苹果好吗？”
“就这个，这个最好了."
“你看，有草莓、香蕉和青苹果。可是，我还没有篮子。”
“我有篮子.”兔子先生说。
小女孩接过篮子，把红色的草莓、黄色的香蕉、绿色的苹果放进去。礼物准备好了。
“兔子先生，谢谢你。”
“不客气，可以帮你，我也很高兴啊!再见!"