Which of the following about the African bush elephant and the African elephant is true?
A.The WCU are interbreeding those elephants.
B.They are interbreeding species.
C.They are two genetically distant species.
D.They depend on each other for survival.
第1题:
"Hidden" Species May Be Surprisingly Common
Cryptic species animals that appear identical but are genetically quite distant—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.
Reports of cryptic species have increased dramatically over the past two decades with the advent of relatively inexpensive DNA sequencing technology. Markus Pfenninger and Klaus Schwenk, of the Goethe-Universitat, in Frankfurt, Germany, analyzed all known data on cryptic animal species and discovered that they are found in equal proportions throughout all major branches of the animal kingdom and occur in equal numbers in all biogeographieal regions.
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 be many different cryptic species that have low populations and are highly endangered. " Says Pfenninger. Until the genetic information of all species in at least one taxon is thoroughly studied, no one will know just how many cryptic species exist. "It could be as high as 30%. " Pfenninger says.
"I'm extremely surprised by their results. " Says Alex Smith of the University of Guelph in Ontario, Canada. "It's a call to arms to keep doing the broad kind of genetic studies that we are doing. "
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 taxonomic groups is completed, Pfenninger says researchers will be able to decide how many cryptic species exist throughout the animal kingdom.
Examples of cryptic species include the African elephant. A 2001 study found the elephants were actually two genetically distinct, non-interbreeding species, the African bush elephant and the African elephant. The species are currently listed as vulnerable and threatened, respectively, by the World Conservation Union (WCU).
The reclassifications are more than an academic exercise. They define populations that have evolved independently of each other and whose genetic differences can have significant consequences. In the early 1900s misidentification of mosquito species based on morphology confused attempts to control malaria in Europe. Ultimately, what was thought to be a single species was actually made up of six sibling species, only three of which transmitted the disease. "The basic unit in biology is always the species, and you have to know what you are dealing with. " Pfenninger says. Much previous research is now no longer used, he says, because it is not clear what species was being studied.
Which of the following about the significance of the research on cryptic species is NOT true?
A.The results of the research can help the development of many other research areas.
B.The results of the research can help the development of biodiversity estimates.
C.The results of the research can help our understanding of infectious disease evolution.
D.The results of the research can help our understanding of "survival of the fittest. "
第2题:
(ii) Calculate the minimum target contribution to sales ratio (%) at which ‘Nellie the Elephant’ will be
financially viable, assuming that all other data remain unchanged. (4 marks)
第3题:
What does the passage tell about the woman?
A.Her name is Lucy.
B.She was called‘the Elephant Lady’.
C.She helped a tiger,a lion and two bears.
第4题:
Pocahontas talks about the conflict between African tribes and English colonists.()
第5题:
Which of the following was true of the local African slavery?
[ A] Slaves might have their own families.
[ B] The son of a slave might not be a slave.
[ C] Slavery was confmed to the coastal regions.
[D] There was no killing in African slavery.
第6题:
Which of the following statements is true?
A. Telephone was invented by a French engineer.
B. Roman soldiers sent the important message by spelling out the words.
C. African soldiers shouted from tower to tower to pass message.
D. Only by using telephone could people send speech sounds quickly.
52.答案为D 通过电话人们能快速地传递声音信息。其他三句与原文不符。
第7题:
Which of the following is NOT TRUE in the passage?
A. The two-way radio is like a telephone for Australian farmers.
B. Families on large farms could keep in touch with each other by radios.
C. The two-way radio is like a newspaper for Australian farmers.
D. All the Australians live on dry places, and they use radios in many ways.
此题为三正一误的细节题。不符合事实的是D。
第8题:
Which of the following is NOT TRUE according to the passage?
A.The zoo needed more information about the woman.
B.A baby elephant was hurt during the war.
C.The woman lived quite near the zoo.
第9题:
A.larger
B.the large
C.more larger
D.the largest
第10题:
A.the promotion mix
B.the double-edge sword
C.the marketing mix
D.the white elephant