Study: Humans Know How to Throw Their Weight Around

 

When you consider all life on Earth, billions of human beings are a relatively¹ small number when compared to trees, earthworms or even viruses.

But humans really know how to use what little power we have, a new study found. The study is said to be the first of its kind of the effect of life forms on our planet.

Humans only add up to about one ten-thousandth of the life on Earth, the study found. That estimate is based on the dry weight of the carbon that makes up the structure of all living things, also known as biomass.

The Associated Press says the planet’s real heavyweights are plants. They outweigh² people by about 7,500 to 1. In fact, plants make up more than 80 percent of the world’s biomass, the study found. The findings were published May 21 in Proceedings³ of the National Academy of Sciences.

Bacteria are nearly 13 percent of the world’s biomass. Fungi⁴ — things like yeast⁵, mold and mushrooms— make up about 2 percent. These estimates are not very exact. The real numbers could be more or less, but they give an idea of proportion, noted⁶ Ron Milo, who was lead writer of the report. Milo, a biologist, is with the Weizmann Institute of Science in Israel.

“The fact that the biomass of fungi exceeds that of all animals sort of puts us in our place,” said James Hanken, a Harvard University professor. Hanken, a specialist on evolutionary⁷ biology, was not part of the new study.

Still, human beings have an outsized influence on other creatures, the report said. Domesticated⁸ cows and pigs outweigh all wild mammals by 14 to 1, the study found. The world’s chickens are triple the weight of all the wild birds.

Instead of children’s books about elephants and lions, a more honest representation of Earth’s animals would be “a cow next to another cow, next to another cow next to a chicken,” Milo said.

He and the other researchers took studies that looked at biomass for different life forms and combined them. They then considered the effect of climate and other environmental issues to come up with a planet-wide look at the effect of life on the planet.

Removing water from consideration and measuring only dry carbon made it easier for scientists to compare life forms. About one-sixth the weight of a human is dry carbon. Humans are about two-thirds water.

“Even though short in numbers, we have managed to throw a lot of sand in the air and mess up a lot of things,” noted Harvard University biologist E.O. Wilson. Wilson was not involved in the study.

I'm Lucija Millonig.

Words in This Story

earthworm– n.a long worm, a creature, that lives in wet soil

fungus⁹- n.any one of a group of living things (such as molds,

mushrooms, or yeasts) that often look like plants but have no flowers

yeast – n.a kind of fungus that is used in making alcoholic¹⁰ drinks

proportion– n.the relationship of one part to another

evolutionary – adj.of or related to the theory that all living things have come from other life forms that existed in the past

triple– v.to make three times as great or as many

mammal– n.a warm-blooded animal that produces milk for its young

domesticated– adj.trained to accept the care of human beings

manage– v.to make and keep; to have control of

mess – n.som

1 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

2 outweigh   

vt.比...更重，...更重要

参考例句：

• The merits of your plan outweigh the defects.你制定的计划其优点胜过缺点。
• One's merits outweigh one's short-comings.功大于过。

3 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

4 fungi   

n.真菌，霉菌

参考例句：

• Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
• The lawn was covered with fungi.草地上到处都是蘑菇。

5 yeast   

n.酵母；酵母片；泡沫；v.发酵；起泡沫

参考例句：

• Yeast can be used in making beer and bread.酵母可用于酿啤酒和发面包。
• The yeast began to work.酵母开始发酵。

6 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

7 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

8 domesticated   

adj.喜欢家庭生活的；（指动物）被驯养了的v.驯化( domesticate的过去式和过去分词 )

参考例句：

• He is thoroughly domesticated and cooks a delicious chicken casserole. 他精于家务，烹制的砂锅炖小鸡非常可口。 来自《简明英汉词典》
• The donkey is a domesticated form of the African wild ass. 驴是非洲野驴的一种已驯化的品种。 来自《简明英汉词典》

9 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

10 alcoholic   

adj.（含）酒精的，由酒精引起的；n.酗酒者

参考例句：

• The alcoholic strength of brandy far exceeds that of wine.白兰地的酒精浓度远远超过葡萄酒。
• Alcoholic drinks act as a poison to a child.酒精饮料对小孩犹如毒药。