问题 单项选择题

对某地区新引入一种鸟的种群增长速率(增长速率=(出生率-死亡率)/时间)1-7年的调查研究,得到的数据如下表。下列对该鸟种群描述正确的是()

A.种群的年龄组成为稳定型

B.种群数量呈曲线“J”型增长

C.种群增长受种群密度的制约

D.第3—4年中种内斗争最激烈

答案

参考答案:C

解析:

本题中的表格表示的是种群数量增长速率与时间的关系。第1~4年种群数量增长速率不断增大,种群数量增加得越来越快;第4年时种群数量增长速率最大,此时种群数量增加最快;第5~7年种群数量增长速率虽然逐渐减小,种群数量增加得越来越慢,但依然在增多。由此可判断,1~7年内,鸟的种群的出生率大于死亡率,种群的年龄组成为增长型,且数量呈“S”型增长(但未达到K值);第4年时该种群数量为等于K/2,第7年时该种群数量尚未达到K值(环境容纳量;此时种内斗争最激烈,种群数量增长速率最慢,其中种群密度是制约种群增长的因素之一。所以C选项正确。 考点:考查种群数量增长及影响因素。意在考查考生能理解所学知识的要点,把握知识间的内在联系,能用数学方式准确地描述生物学方面的内容、以及数据处理能力。

问答题
阅读理解

B

Babies love chocolate, and sometimes they also eat the paper around it. My cat enjoys a meal of good, thick paper, old letters, for example . She doesn't like newspapers very much .

Of course, the best paper comes from wood. Wood comes from trees , and trees are plants: Vegetables and fruit are plants too, and we eat a lot of them . So can we also eat wood and paper?

Scientists say: “ All food comes in some way from plants. ” Well, is that true? Animals eat grass and grow fat. Then we eat their meat. Little fish eat sea-plants; then bigger fish swim along and eat them . Chickens eat bits of grass and give us eggs . What food does not come from plants in some way?

Scientists can do wonderful things with plants . They can make food just like meat. And they can make it without the help of animals . It is very good food, too . Now they have begun to say : “ We make our paper from wood . We can also make food from wood . The next thing is not very difficult . ”

What is the next thing? Perhaps it is food from paper. Scientists say;“We can turn paper into food . It will be good , cheap food too : cheaper than meat or fish or eggs . ”

So please keep your old books and letters . One day , soon , they will be on your plate. There is nothing like a good story for breakfast .

6.People live mainly on ______.                   

A.paper          B.plants        C.fish           D.meat

7.Scientists have ______.                    

A.made a lot of paper   B.fed eggs to chickens

C.made food just like meat D.made meat cheaper than food from paper

8.Chickens eat bits of grass . In the sentence “bits of” means _________________________.   

A.a little of    B .lots of  C.big pieces of    D .small pieces of

9.Which of the following is NOT true?           

A.Scientists say, “All food comes in some way from plants . ”

B.Scientists can make wood into food some day.

C.Scientists can make food from paper some day.

D.Scientists advise us to eat old books and letters at meals .

10.Choose one of the following as the topic for the passage .   

A.Paper----Our Future Food   B.No More Meat in Future

C.Save Old Books for Breakfast  D.Paper----The Best Cat Food