【正文】 y – a radical plan, involving large vertebrates, or,megafauna. Megafauna include elephants, wild horses, big cats, camels, large animals. Eh, actually,the proposal focuses on a particular subset ofmegafauna, the kind that lived during thePleistocene epoch. OK. The Pleistocene epoch, most monly known as the Ice Age,stretched from million to 11,500 years ago. In the Americas,many megafauna began disappearing bythe end of the Pleistocene. So here’s the biologists’ idea. Takea selectgroup of animals, megafauna from places like Africa and Asia, and introduce them into other systemssimilar to theircurrent homes, beginning in the westernUnited States. Theycalltheir plan Pleistocene rewilding . 全國免費(fèi)咨詢電話： 4000123267 Now,the advocatesof Pleistocene rewilding cite two main goals. One is to help prevent the extinction ofsome endangered megafauna by providing new refuges,new habitats for them. The other is torestore some of theevolutionary and ecological potentialthat has been lost in North America. What do I mean by restoreevolutionary potential? Well,as you know, theevolution of any species is largely influenced by itsinteractionswith otherspecies. So during thePleistocene epoch ...Let ’s takethe now extinct American cheetah, for instance. We believe it played a pivotal role in the evolution of the pronghorn antelope,the antelope’s amazing speed, tobe exact,because natural selection would favor those antelope that could outrun a cheetah. When the American cheetahs disappeared, their influence on theevolution of pronghorn and presumably6 on other preyanimals stopped. So it is conceivable7 that the pronghorn antelope would have continued to evolve,get faster maybe, if thecheetahs werestill around. That ’s what ’s meant by evolutionary potential . Importing African cheetahsto the westernUnited Statescould, in theory,put the pronghorn back onto its...uh, natural evolutionary trajectoryaccording to these biologists. Another example is the interaction of megafauna with local flora, in particular,plants that relyon animals to disperse their seeds .Like Pleistocene rewilding could spark thereemergence of large 全國免費(fèi)咨詢電話： 4000123267 seeded American plants, such as the maclura tree .Many typesof maclura used to grow in North America,but today,just one varietyremains and it is found in only two the distant past, large herbivores like mastodons8 dispersed maclura seeds, each the size of an orange in their droppings. Well, therearen’tany mastodons left, but thereare elephants, which descended from mastodons. Introduceelephants into that ecosystem and theymight disperse those large maclura seeds, like their ancestorsdid. Getthe idea? Restoring some of theformer balance to theecosystem? Butas I alluded to earlier, Pleistocene rewilding is extremelycontroversial. A big worry is that these transplanted megafauna might devastateplants and animals that arenative to thewestern United the yearssince thePleistocene epoch, native species have adapted to thechanging environmentalthere,plants, smaller animals, theyhave been evolving without megafauna for millennia. Also, animal species that went extinct 11,000 years ago, uh, some are quite different geicallyfrom their modernday counterparts, like elephants don’t have thick coatslike their mastodon ancestorsdo when theygrazethe prairies ofthe America West during the Ice Age. Granted,the climate today is not as cold as it was in thePleistocene. Butwinterson the prairie can still get prettyharsh thereare many more considerations. Well,you see how plex this is. Ifyou think about it though, thecore problem with thissixth mass extinction is 全國免費(fèi)咨詢電話： 4000123267 human interference. LectureMusic History(Musicians amp。 everybody knows it is not true. Student But Ithought we could expectbetter than that here. Faculty Advisor Well, Iam certainly in favor of getting a varietyof viewpoints. 【 So whydon’t you go talk to the editor,Jennifer Hamilton, and tellher you want equal time?You or Sally could writea response. 】 Student 【 Really? She would let us do that?】 Didn’t she write it? Faculty Advisor I’ll letJennifer know you are ing, she feelsthe same wayI do. She is journalism would be happy to publish another point of view. Sarcastic. A satirical drawing, piece of writing, or edy show is one in which humour or exaggeration is used to criticize something. LectureAnthropology(State Formation) Narrator Listen to part ofa lecturein an anthropology class. Professor One of the big questions when we look at prehistoryis: Why did the earliest statesform? 全國免費(fèi)咨詢電話： 4000123267 Well, to begin we’d betterdefine exactlywhat w