题干

请根据调查某双子叶草本植物种群密度的过程,回答下列问题:

(1)样方法调查时,取样的关键是要做到随机取样,不能掺入主观因素.常用的取样方法有____ 和____ ,其中____ (方法)适用于调查地块的长与宽相差不大的地块.

(2)调查不同的植物类型时样方面积应该不同,如调查乔木种群密度时样方面积要比调查草本植物种群密度时的样方面积____ 

(3)某同学采用样方法对一种植物进行计数,如图是其中一个样方中该植物的分布情况(注:图中黑点表示该种植物),对该样方中该种植物进行计数时,应记录的数目是____ .

(4)若某长条形地块长、宽为100m×50m,如果要等距抽取10个样方,则抽样时相邻样方的中心距离为____ .若调查中小样方为1m×1m,对某种植物种群调查的结果为:12、18、16、16、15、13、15、11、13、13,则所调查种群的密度为____ .

上一题 下一题 0.0难度 选择题 更新时间:2019-10-30 03:02:32

答案(点此获取答案解析)

五点取样法,等距取样法,五点取样法,大,8,10m,14株/㎡

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回答问题,请阅读下面这篇文章,根据文章内容用完整句子回答下列问题,

                                                                                     Welcome to my blog

Stephen Williams   Friday, June 21

      Today I went to the beach. It was my first day at the ocean for many years. The sound and smell of the ocean brought back memories of the great family vacations when I was a child. We always went to the beach for a week in the summer. I remembered playing for hours in the sand with my sister and crying when I couldn't have any ice cream. Oh, and I remembered finding a huge jellyfish on the beach, and running away because I was scared! Amazing, really, the things you remember from your childhood...

Comments

    Yeah, I remember going for long walks in the countryside. I guess I was only eight or nine. In the winter, my mom made soup, and I can still remember the wonderful smell! When we got home, I always went straight to sleep...

Carla, Mexico

    What a great story! I remember going to the beach, too – on Christmas Day! My family lived in Australia when I was young. I remember waking up early. After we opened our presents, we always went to the beach and had a barbecue.

Leung, Hong Kong

    The best memory I have is playing my first video game, Super Mario. I remember thinking that it was amazing, It was my tenth birthday and I still remember opening the box.

Daisuke, Japan