Hidden Species May Be Surprisingly Common
Cryptic species animals that appear identical but are genetically quite distant一may be much more widespread than previously thought. The findings could have major implications in areas ranging from biodiversity estimates and wildlife management,to our understanding of infectious diseases and evolution.
Scientists had previously speculated that cryptic species were predominantly found in insects and reptiles,and were more likely to occur in tropical rather than temperate regions. Species that are seemingly widespread and abundant could in reality he many different cryptic species that have low populations and are highly endangered, says Henninger. Until the genetic information of all species. in at least one texon is thoroughly studied, no one will know just how many cryptic species exist. It could be as high. as 30%,Pfenninger says
Sampling as many individuals as possible, scientists hope to complete work on all fish and birds in another 5 to 10 years. Once either of these taxonumic groups is completed. Pfenninger says researchers will be able to decide how many cryptic species exist throughout the animal kingdom.
The reclassifications are more than an academic exercise: They define populations that have evolved independently of each other and whom genetic differences that have evolved independently of each other and whose genetic differences can have significant consequences.
1.Which of the following about the significance of the research on cryptic species is NOT true?
B The results of the research can help the development of biodiversity estimates.
D The results of the research can help our understanding of survival of the fittest.
A They occurred in equal numbers in all biogeographical regions
C They were likely to be in tropical rather than temperate regions
3. Do scientists know how many cryptic species exist?
B Yes. they do.
D They will never know the answer.
A The WCU are interbreeding those elephants
C They are two genetically distant species.
2012年PETS三级词汇记忆:比较记忆法
09PETS二级考试精品阅读文章02
PETS阅读技巧:树立大阅读观念
新东方PETS2阅读应试指南(2)
公共英语四级考试翻译解题技巧总结
09PETS二级考试精品阅读文章03
09PETS二级考试精品阅读文章06
考研英语作文闪光词汇分享
考研英语作文预测及范文(1)
PETS英语考场技巧:巧答题得高分
考研英语作文预测及范文(3)
公共英语三级PETS3作文经典辅导
PETS考试指导:如何提高阅读效率
考研英语写作之环境保护类范文1
2012年公共英语三级阅读理解辅导
考研英语作文预测及范文(4)
2012年PETS三级词汇记忆:构词法记忆法
轻松学语法应对公共英语考试
09PETS二级考试精品阅读文章04
公共英语阅读考试技巧
公共英语三级考试成绩快速提高方法指点
PETS考试各题型注意事项
考研英语作文预测及范文(5)
09PETS二级考试精品阅读文章05
考研英语写作指导及方法
考研英语写作常用句型
考研英语作文预测及范文(2)
新东方PETS2阅读应试指南(3)
公共英语等级考试写作的练习技巧
新东方PETS2阅读应试指南(1)
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |