问题 实验题

下图表示某生态系统部分生物的营养关系图解。请回答下列问题。

(1)图中的生物由于食物关系而形成一个食物网,如需构成一个完整的生态系统,图中还应加入的成分有____________和______________。

(2)图中食物网中,共有_______条食物链。请写出该生态系统中最长的食物链_____(只写一条)。蛇和鹰之间属于____________和______________关系。

(3)该生态系统中含能量最多的类群是_____________,生态系统中的能量均来自于这一类群通过______________固定太阳能。

(4)假若在生态系统中施用了不易分解的农药,该食物网中农药含量最高的生物类群是_______________。

(5)如果蝗虫的数量大量增加,食虫鸟和蛙的数量将随之增加,使蝗虫的数量增长受到抑制,这体现了生态系统具有_____________能力。

答案

(1)分解者 非生物部分

(2)4  植物→蝗虫→蛙(食虫鸟)→蛇→鹰  捕食 竞争

(3)植物 光合作用

(4)鹰  

(5)自动调节

题目分析:(1)在一个生态系统中,有生物部分和非生物部分,而生物部分包括生产者、消费者、分解者,生产者和消费者构成食物链和食物网,是生态系统的营养结构,图中植物是生产者,而鼠、食虫鸟、青蛙和蛇等动物属于消费者,所以生物部分缺少的是分解者,即细菌、真菌等。

(2)图中共有4条食物链,分别是植物→鼠→蛇→鹰;植物→蝗虫→蛙→蛇→鹰;植物→蝗虫→食虫鸟→蛇→鹰。

植物→蝗虫→食虫鸟→鹰;蛇以蛙为食物,故蛇和蛙之间属于捕食关系。

(3)在一个生态系统中,生物部分包括生产者、消费者、分解者,含能量最多的类群是生产者即植物,植物通过光合作用把光能转化为化学能储存在有机物中,因此,生态系统中的能量均来自于植物通过光合作用固定的太阳能。

(4)有毒物质在生物体内不易被排出和分解,随着食物链逐级积累,农药作为一种剧毒物质,鹰的营养级别最高,所以它的体内农药的含量最多。

(5)一般正常情况下,该生态系统中各种生物的数量会处于相对稳定状态,说明生态系统具有一定的自我调节能力。

点评:此题综合性强,难度一般,解此题的关键是掌握图形中的结构及各部分结构的功能.搞清楚生态系统中的各种成分之间的关系,如物质流动、能量流动关系等。

问答题 简答题
单项选择题

There is virtually no limit to how one can serve community interests, from spending a few hours a week with some charitable organization to practically full-time work for a social agency. Just as there are opportunities for voluntary service (1) (VSO) for young people before they take up full-time employment, (2) there are opportunities for overseas service for (3) technicians in developing countries. Some people, (4) those who retire early, (5) their technical and business skills in countries (6) there is a special need.

So in considering voluntary or (7) community service, there are more opportunities than there (8) were when one first began work. Most voluntary organizations have only a small full-time

(9) and depend very much on volunteers and part-timers. This means that working relationships are different from those in commercial organizations, and values may be different. (10) some ways they may seem more casual and less efficient, but one should not (11) them by commercial criteria. The people who work with them do so for different reasons and with different (12) , both personal and (13) . One should not join them (14) to arm them with professional experience; they must be joined with commitment to the (15) , not business efficiency. Because salaries are (16) or non-existent many voluntary bodies offer modest expense. But many retired people take part in community service for (17) , simply because they enjoy the work.

Many community activities possible (18) retirement were also possible during one’s working life but they are to be undertaken (19) seriously for that. Retired people who are just looking for something different or unusual to do should not consider (20) community service.

4()

A.partially

B.partly

C.particularly

D.passionately