首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Can eating a cheeseburger be considered an act of war? Yes, but only if you understand the delicate and intricate relationship o
Can eating a cheeseburger be considered an act of war? Yes, but only if you understand the delicate and intricate relationship o
admin
2015-01-09
21
问题
Can eating a cheeseburger be considered an act of war? Yes, but only if you understand the delicate and intricate relationship of the many living creatures on Earth.
Consider first the place humans occupy in the food chain. We think of ourselves as being on top, right? We are not, generally speaking, hunted and consumed by other animals and being humans, we like to think we’re king of the hill, A-number-one.
But according to a new study published in the journal Proceedings of the National Academy of Sciences, Homo sapiens are at roughly the same level as pigs and anchovies. If it’s any consolation, the report says our species is moving up in the rankings—but that could be seriously bad news for the planet.
Biologists don’t really like the term food chain anymore. Chains are linear, while nature is multidimensional, to say the least. Instead they speak of food webs, often with vast numbers of different trophic levels shared by different organisms, like neighbors in a New York high-rise. The living things that used to occupy the bottom of the food chain—algae and multicellular plants—are now said to inhabit "trophic level 1. " They are autotrophs, manufacturing their own food through photosynthesis. Trophic level 2 consists of rabbits and other basic herbivores, which get their energy by eating plants.
Simple, right? From there, however, the trophic numbers get complicated. Many species subsist on mixed diets of animal and vegetable protein. Take foxes: If they ate nothing but rabbits, you could call them level 3. Unfortunately, they also eat fruit, so their trophic score might be less than a full 3. At the same time, some animals prey on other predators. You might be tempted to call them "trophic level 4" and be done with it—but again, take foxes. Besides eating fruit and herbivores, they also catch and consume level-3 animals like moles and other insectivores.
So how do scientists even begin to crunch the fox’s trophic numbers? First they need an army of graduate students and a calculator with plenty of decimal places. Field zoologists are a tough and determined breed. Species by species, they are mapping the global food web, all the way up to the "apex predators" at trophic level 5(or higher, depending on who’s keeping score)—tigers, killer whales, and the like—what everyone once called the top of the food chain.
Science had never settled on a trophic level for humans—until now. It’s not easy to quantify the eating habits of the most diverse, widespread, and omnivorous species of all. But the newly published study, led by fisheries scientist Sylvain Bonhommeau of the French Research Institute for Exploitation of the Sea, attempts to change that. Using the most recent data from the United Nations Food and Agriculture Organization, Bonhommeau and his team have estimated that as of 2009, humanity’s worldwide median trophic level was approximately 2.21—"closer to a herbivore than a carnivore," as Bonhommeau told Nature. "It changes the preconception of being top predator. "
The worrisome part is what else they discovered: Our global population is growing more and more carnivorous, and that trend threatens to send us off an environmental precipice. Humanity’s meat market has more than quadrupled since 1961, from about 70 million tons back then to almost 300 million tons in 2010, according to the FAO. Much of that increase has come from India and China. Those two countries, accounting for about a third of the world’s total population, once relied mostly on rice and vegetables to feed their people. Now their booming economies are enabling them to buy meat, and vast tracts of Amazon rainforest are being clear-cut to satisfy the unprecedented demand for corn and soybeans as animal feed.
And that’s not all that humanity’s appetite for meat is doing to the world. The livestock industry accounts for some 18 percent of global greenhouse gas emissions, according to a 2006 FAO study. Then there’s the grain and water it takes to raise cattle. NPR ran the numbers and found that it takes 6.7 pounds of grain and forage and 52.8 gallons of water to produce a single quarter-pound ground-beef patty—hold the pickle, the lettuce and the bun.
And Americans are in no position to wag a finger. Despite the incessant claims on talk shows that they’re eating healthier these days, Americans remain among the most voraciously carnivorous people on the planet, devouring 270. 7 pounds of meat a year per capita. That’s way more than double the world average of 102.5 pounds.
It’s worth remembering that we’re all part of the food web. If it were a chain, humans might be able to keep up our predatory ways with impunity. But in a web, what goes around is likely to come around.
Nowadays, biologists tend to believe that humans
选项
A、occupy the top of the food chain.
B、inhabit the same level as anchovies.
C、rank above autotrophs and herbivores.
D、move up to the trophic level of pigs.
答案
C
解析
推断题。第三段提到,人类在食物链中大致与猪和凤尾鱼处于同一级别,且人类的排名呈上升状态。第四段提到处于营养级1的是autotrophs“自养生物”,而处于营养级2的是herbivores“食草动物”,结合第七段倒数第二句提到的“人类的营养级接近于2.21”,由此可知,人类的营养级在自养动物和食草动物之上。根据文意可以推出答案为[C]。
转载请注明原文地址:https://kaotiyun.com/show/PfdO777K
0
专业英语八级
相关试题推荐
WhichofthefollowingstatementsisINCORRECTaboutMissChan?
Whichofthefollowingitalicizedpartsisaninflectionalmorpheme?
WhatDoActiveLearnersDo?Therearedifferencesbetweenactivelearningandpassivelearning.Characteristicsofacti
Humanintelligencetechnologyhasbeenthrivingoverthepastdecade.Now,wehavesuper-computersthatevenbeathumansinches
IntroductoryLecturetoUniversityStudyInordertoadjustwelltouniversitylife,freshmenusuallyhavetounderstandthe
HenryFielding,thefamousnovelistwhowasalsoaLondonmagistrate,oncemadeanightraidto【M1】______twoknownhideo
Somepeoplethinkchildrenofdifferentabilitiesshouldbeeducatedtogetherbecauseitbenefitseveryone.Othersholdthatint
WhatarethemostimportantnaturalresourcesinCanada?
Thereare______morphemesintheword"boyish".
WhichofthefollowingworksisNOTwrittenbyWilliamShakespeare?
随机试题
A、氟尿嘧啶B、环磷酰胺C、阿霉素D、紫杉醇E、肾上腺皮质激素直接影响和破坏DNA结构及功能的药物
关于痛经错误的是
某化学成分,可将皮肤染成蓝色,该成分可能为()。
《城市国有土地使用权出让转让规划管理办法》的适用范围是()。
工程材料的检验程度,有( )三种类型。
快速决策分析与其说是一项具体分析技术,莫如说是一种方法论,快速决策分析法强调对决策问题的()。
几个诚实的商人合开了一个店铺,等到赚得许多钱财,他们便停业分钱分物。但分红哪能不吵架?他们为钱为物吵得一塌糊涂。这时他们的房子着火了,但他们仍在为钱争论。他们争吵得忘了房子已经起火,以至全都被火焰吞没烧死,连同他们的财物。从文中可以得出的道理是(
在进行消息认证时,经常利用安全单向散列函数产生消息摘要。安全单向散列函数不需要具有下面哪个特性________。
设表的长度为20。则在最坏情况下,冒泡排序的比较次数为
Sheisthe______holderofthe3,000-meterworldrecord,butthereisnoguaranteethatshewillwinintheOlympicGames.
最新回复
(
0
)