问题
单项选择题
关于群落与环境关系的论述,不正确的是()。
A.群落只是被动受环境制约
B.群落在环境制约下具有一定的分布和特征
C.群落可形成内部特殊环境
D.需要特殊环境的群落对环境具有指示意义
答案
参考答案:A
关于群落与环境关系的论述,不正确的是()。
A.群落只是被动受环境制约
B.群落在环境制约下具有一定的分布和特征
C.群落可形成内部特殊环境
D.需要特殊环境的群落对环境具有指示意义
参考答案:A
Since life began eons ago, thousands of creatures have come and gone. Some, such as the dinosaurs, became extinct due to naturally changing ecologic conditions. More recent threats to life forms are humans and their activities. Man has drained marshes, burned prairies, dammed and diverted rivers. Some of the more recent casualties of man’s expansion have been the dodo, great auk, passenger pigeon, Irish elk, and Steller’s sea cow. Sadly, we can no longer attribute the increasing decline in our wild animals and plant species to "natural" processes. Many species are dying out because of exploitation, habitat alteration or destruction, pollution, or the introduction of new species of plants and animals to an area. As mandated by Congress, protecting endangered species, and restoring them to the point where their existence is no longer jeopardized, is the primary objective of the U.S. Fish and Wilidlife Service’s Endangered Species Program. |
Which of the following is a form of man’s habitat alteration
A.Glacial encroachment
B.Hurricanes
C.Dammed rivers
D.Snowstorms