Plankton
Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger animals. Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far outweighs that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carbohydrates each year, the seas plankton generates more than twice as much. Despite its enormous food potential, little effect was made until recently to farm plankton as we farm grasses on land. Now marine scientists have at last begun to study this possibility, especially as the seas resources loom even more important as a means of feeding an expanding world population. No one yet has seriously suggested that planktonburgers may soon become popular around the world. As a possible farmed supplementary food source, however, plankton is gaining considerable interest among marine scientists. One type of plankton that seems to have great harvest possibilities is a tiny shrimplike creature called krill. Growing to two or three inches long, krill provide the major food for the great blue whale, the largest animal ever inhabit the Earth. Realizing that this whale may grow to 100 feet and weigh 150 tons at maturity, it is not surprising that each one devours more than one ton of krill daily.
2012年考研英语阅读训练五
2012年考研英语阅读训练三十一
2012年考研英语阅读训练三十三
2012考研阅读资料经典美文37
2012年考研英语阅读训练十二
2012年考研英语阅读训练十八
2012考研阅读资料经典美文42
2012年考研英语阅读训练三十二
2012年考研英语阅读训练三十四
考研基础班的阅读讲义
2012年考研英语阅读训练四
2012考研阅读资料经典美文50
2012年考研英语阅读训练八
考研英语阅读理解复习冲刺
2012年考研英语阅读训练六
世界杯口号巴西最霸气意大利很浪漫
2012年考研英语阅读训练二
2012年考研英语阅读训练二十二
考研英语阅读训练二十一
考研英语阅读理解精读100篇UNIT6
2012年考研英语阅读训练二十七
2012年考研英语阅读训练九
2012年考研英语阅读训练十七
2012年考研英语阅读训练十三
考研英语阅读理解精读100篇UNIT8
考研英语阅读理解精读100篇UNIT18
2012年考研英语阅读训练三十
2012考研阅读资料经典美文45
2012考研阅读资料经典美文47
考研冲刺阅读面面观
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |