A gradual agricultural revolution in northern Europe stemmed from concerns over food supplies at a time of rising populations.
北欧渐进的农业革命源于人口增长时期对粮食供应的担忧。
Indeed, most analysts believe that some kind of environmental degradation underlies the demise of many extinct salmon populations.
事实上，大多数分析家认为某种环境退化是许多已灭绝鲑鱼种群消亡的根源。
After the islands separated, the isolated lizard populations would have become distinct species while also retaining their ancestors' niche adaptations.
岛屿分离后，孤立的蜥蜴种群将成为独特的物种，同时也保留了它们祖先的生态适应能力。
While most old universities have modernised radically to accommodate their growing populations, Oxford has managed to expand while still preserving its traditional structure.
当大多数古老的大学都进行了彻底的现代化以适应它们不断增长的人口时，牛津大学却成功地在扩张的同时保留了它的传统结构。
Du Bois was concerned that race was being used as a biological explanation for what he understood to be social and cultural differences between different populations of people.
杜·波依斯担心，种族会被用来作为生物学层面上的一种解释，并用以说明他所理解的不同人群之间的社会和文化差异。
Deer and elk populations—major food sources for the wolf—grew rapidly.
鹿和麋鹿的数量迅速增长，它们是狼的主要食物来源。
By competing with rodents for seeds, black ants help control rodent populations that pose a public health risk.
通过与啮齿动物争夺种子，黑蚂蚁有助于控制啮齿动物的数量，这些啮齿动物会对公众健康构成威胁。
Between 1940 and 1959, overfishing led to crashes in salmon populations so severe that in 1953 Alaska was declared a federal disaster area.
1940年至1959年间，过度捕捞导致鲑鱼数量锐减，以致于1953年阿拉斯加被指定为联邦灾区。
Fewer otters would have allowed sea urchin populations on which the otters preyed to expand and the urchins' grazing pressure on kelp forests to increase.
海獭的减少会使海胆的数量增加，因为海獭以此为食，从而增加海胆对海藻林的食草压力。
In developing countries many rural people and traditional forest dwellers have remarkable knowledge about managing insect populations to produce food.
在发展中国家，许多农村居民和传统森林居民在管理昆虫以生产粮食方面具有丰富的知识。
On the bright side, in all the research being done on causes, we have discovered something related to how starfish populations might affect coral reef diversity.
好的一面是，我们在所有关于起因的研究中，发现了一些关于海星数量如何影响珊瑚礁多样性的内容。
These settlements acted like small towns, becoming centers for the artisan and trading populations.
这些居留地就像小城镇，成为了工匠和生意人的聚集地。
He's the conservation director for Rewilding Argentina, which is one of the organizations helping to restore jaguar populations.
他是阿根廷再野化组织的保护主任，该组织是帮助恢复美洲虎种群数量的组织之一。
South Georgia's king penguin populations too are soaring.
南乔治亚的王企鹅数量也剧增。
“Outmigration” has drained their populations over the past century.
一个世纪以来，这些小镇的居民不断迁走，人口流失严重。
But the good news is we have also found that tiger populations can recover.
不过好消息是我们也发现老虎的种群数量是可以恢复的。
We will continue to increase support to ethnic groups with small populations.
继续加大对人口较少民族的扶持力度。
All populations are vulnerable, but the poor are the first and the hardest hit.
所有的人群都是脆弱的，但穷人首当其冲，受到的影响最大。
By contrast, the faith of Asian populations in free trade is growing stronger.
与之相反，亚洲民众对自由贸易的信念正变得越来越坚定。
Nobody owns the earth’s fish populations, indeed, they are a shared resource.
地球上的渔业资源并非为任何人所有，因而是共享资源。
Top predators are key to keeping populations of key species from growing too large.
大型捕食者是使主要的物种种群不会生长过大的关键因素。
In the future, work will focus even more on those countries and populations most in need.
今后，工作将更多注重于最需要的国家和人群。
But scientists have the tools to engineer crops that can benefit far needier populations.
但科学家们有办法研制出造福更多民众的作物。
It remains in populations because the mutation has a flip side—it helps to protect against malaria.
而那种变异基因没有被生物进化所淘汰，仍然存在于人群之中，其原因在于它也有益处——它能保护人体抵御疟疾的侵袭。
It remains in populations because the mutation has a flip side—it helps to protect against malaria.
而那种变异基因没有被生物进化所淘汰，仍然存在于人群之中，其原因在于它也有益处——它能保护人体抵御疟疾的侵袭。
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