题干

小型动物线虫普遍存在各类土壤中,其类群和数量极丰富,被看作是生态系统变化的每感性指示生物之一.我省沿海某湿地的三个群落中土壤线中调查结果如下表所示:

湿地类型

线虫属丰富度

土层深度(cm)

植物寄生线虫(条/100g干土)

腐食线虫(条/100g干土)

食细菌线虫(条/100g干土)

碱蓬群落

19

0﹣10

93

15

12

10﹣20

14

2

10

柳群落

18

0﹣10

89

19

28

10﹣20

21

0

15

白茅群落

24

0﹣10

598

92

71

10﹣20

163

9

7

请据表中数据回答:

(1)科研人员调查土壤中的线虫时,常采用____ 的方法进行采集、调查.首先在三个群落内各选取5个采集点,每个土样分0﹣10cm、10﹣20cm两层,在设置采集点时应做到____ 选择地点.

(2)腐食线虫属于湿地生态系统的____ 成分,生活污水的直接排放使此类线虫和表中____ 线虫数量明显增多

(3)表中三个群落的____ 线虫均为绝对优势类群,且各营养类型的线虫都“表层聚集”分布.从线虫的取食习惯分析,这种现象主要原因是①湿地植物的根系主要分布在____ (cm)②深层土壤中____ 积累较少

(4)根据表中数据分析,营养结构最复杂的群落可能是____ ,因为该群落土壤线虫的____ 最高.

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答案(点此获取答案解析)

取样器取样,随机,分解者,食细菌,植物寄生,0—10,有机质,白茅群落,丰富度

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    I grew up poor. We had little money, but plenty of love and attention. I understood that no matter how poor a person was, he could still afford a dream. My dream was athletics.

    By the time I was sixteen, I was good at baseball and football. My high-school coach was Ollie Jarvis. He not only believed in me, but taught me the difference between having a dream and showing conviction(信念).

    One summer a friend recommended me for a summer job. This meant a chance for money in my pocket — cash for dates with girls, certainly, money for a new bike and new clothes, and the start of savings for a house for my mother.

    Then I realized I would have to give up summer baseball to handle the work schedule, and that meant I would have to tell Coach Jarvis I wouldn't be playing. I was dreading(害怕) this, but my mother said, “If you make your bed, you have to lie in it.”

    When I told Coach Jarvis, he was as mad as I expected him to be. “Your playing days are limited. You can't afford to waste them,” he said.

    I stood before him with my head hanging, trying to think of the words that would explain to him why I dreamed of buying my mom a house.

    “How much are you going to make at this job, son?” he demanded.

    “Three twenty-five an hour,” I replied.

    “Well,” he asked, “is $3.25 an hour the price of a dream?”

    That question laid bare for me the difference between wanting something right now and having a goal. I devoted myself to sports that summer, and within the year I was drafted by the Pittsburgh Pirates to play rookie-league ball, and offered a $20,000 contract. I signed with the Denver Broncos in 1984 for $1.7 million, and bought my mother the house of my dream.