题干

现有一未受人类干扰的自然湖泊,某研究小组考察了该湖泊中处于食物链最高营养级的某鱼种群的年龄组成,结果如表.

年龄

0+

1+

2+

3+

4+

5+

6+

7+

8+

9+

10+

11+

≥12

个体数

92

187

121

70

69

62

63

72

64

55

42

39

264

注:表中“1+”表示鱼的年龄大于等于1、小于2,其他以此类推.

回答下列问题:

(1)通常,种群的年龄结构大致可以分为三种类型,分别是增长型、稳定型、衰退型.研究表明:该鱼在3+时达到性成熟(进入成年),9+时丧失繁殖能力(进入老年).根据表中数据可知幼年、成年和老年3个年龄组个体数的比例为____ ,由此可推测该鱼群年龄结构____,数量的变化趋势是____ 

(2)在该湖泊中,能量沿食物链流动时,所具有的两个特点是____ 

(3)如果要调查这一湖泊中该鱼的种群密度,常用的调查方法是____ .

上一题 下一题 0.0难度 选择题 更新时间:2011-03-29 03:12:56

答案(点此获取答案解析)

1:1:1 ,稳定型,保持稳定,单向流动、逐级递减,标志重捕法

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