41. 动物的光周期现象
• 许多动物的行为对日
照长短也表现出周期
性。鸟、兽、鱼、昆
虫等的繁殖,以及鸟、
鱼的迁移活动,都受
光照长短的影响
Seasonal dawn-song is timed according to annual increases in day length. Data were collected
from March 2011 until December 2012. Variations in monthly rainfall (mm3) are shown in blue. The
small changes in day length duration (hours from sunrise to sunset) over the year are shown in
yellow. Seasonal periods in which dawn-song is produced by males are shown in red. The
seasonal timing of dawn-song is highly regular between years.
110. 群落变化
Many small freshwater planktonic animals move vertically
during the daily cycle of illumination somewhat as shown here
(widths of bands represent the density of animals at a given
depth at a particular time). [After Cowles and Brambel 1936].
• 自然界中的群落并非永
久不变,而是随时间的
推移而不断产生动态的
变化。
• 群落的动态变化一般可
以分为内部的动态变化
和消长zhǎng两种型式。
111. 群落变化
Many small freshwater planktonic animals move vertically
during the daily cycle of illumination somewhat as shown here
(widths of bands represent the density of animals at a given
depth at a particular time). [After Cowles and Brambel 1936].
• 自然界中的群落并非永
久不变,而是随时间的
推移而不断产生动态的
变化。
• 群落的动态变化一般可
以分为内部的动态变化
和消长两种型式。
• 群落的内部动态变化是
指群落内的生物族群,
由于受到环境因素变化
的影响,而产生周期性
变化的现象。
112. 群落变化
Many small freshwater planktonic animals move vertically
during the daily cycle of illumination somewhat as shown here
(widths of bands represent the density of animals at a given
depth at a particular time). [After Cowles and Brambel 1936].
• 若变化的周期约为一天
者,称为日变化;
• 若是随季节的更替而变
化的称为季节变化;
• 若组成群落的生物种群
因年度的不同而改变者
称为年变化。
135. 热带雨林的物种
• 种类繁多
This map illustrates the number of
amphibian species across the
globe and shows the trend toward
higher biodiversity at lower
latitudes. A similar pattern is
observed for most taxonomic
groups.
137. 热带雨林的产品
• 树桐
• 树脂
• 藤
• 水产动物的繁殖与庇护所
• 碳制燃料
Non-timber forest products and their contribution to
households income around Falgore Game Reserve in
Kano, Nigeria
213. 臭氧层破洞 Ozone depletion
• 地球大气上空平流层(臭
氧层)的臭氧O3从1970年
代开始,以每十年4%的速
度递减的一种现象。
• 臭氧层可以吸收波长为
315–280纳米的紫外线,
所以臭氧层的被消耗会导
致增加这种紫外线对地面
的辐射。 The Solar map below domonstrates how the average
annual ground solar radiation varies across the surface of
the earth.