但是利用现存物种的DNA重建哺乳动物系统树的生物学家却得出了不同的结论。
But biologists reconstructing the mammalian tree of evolution from the DNA of living species have come to a different conclusion.
在他看来，在白垩纪虱子物种进化时的宿主可能是哺乳动物系统树上的另一分支而这一分支上的所有物种都灭绝了。
In his view, the hosts on which lice were speciating during the Cretaceous could have been a different branch of the mammalian family tree, all of whose species are extinct.
牧场主正在检测动物耳朵上的跟踪器，以建立一个全国性的家畜跟踪系统。
Ranchers are testing electronic tags on animals' ears to create a national cattle-tracking system.
教授一直在讨论“动物交流系统”。
The professor has been discussing Animal Communication Systems.
动物有本能的交流系统。
当他们开始定居、种植作物和饲养动物时，他们对复杂数字系统的需求变大。
As they began to settle, grow plants and herd animals, the need for a sophisticated number system became paramount.
作为交换，他向客户保证以高于市场的价格收购每一头动物，并为牛崽提供与欧盟类似的直达客户电子耳标身份识别系统。
In exchange, he guarantees an above-market price for each animal and a calf-to-customer electronic ear tag ID system like that used in the European Union.
先锋植物种子的增加，被猎杀的动物以及用于建筑和燃料的树木系统的变化是环境退化的证据。
Increases in seeds from pioneer plants and systematic changes in the animals hunted and the trees used for construction and fuel are evidence of environmental degradation.
玩耍似乎是具有相当复杂的神经系统的动物（主要是鸟类和哺乳动物）的一种发育特征。
Play appears to be a developmental characteristic of animals with fairly sophisticated nervous systems, mainly birds and mammals.
在弗兰纳里1994年出版的《未来的食客》一书中，他阐述了自己的论点，人类是地球上的一种新型动物，而且是一种倾向于破坏生态系统的新型动物。
In Flannery's 1994 book called The Future Eaters, he sets out his thesis that human beings are a new kind of animal on the planet, and are in general, one prone to ruining ecosystems.
先锋植物种子的增加和被猎杀动物的系统性变化是环境退化的证据。
Increases in seeds from pioneer plants and systematic changes in the animals hunted are evidence of environmental degradation.
我们参与反核活动，保护动物，以及维持和保护我们的生态系统。
We're involved in anti-nuclear activity, conservation and protection of animals and protection and support of our eco-system.
现在，在湖泊生态系统的草原上，我们可以预料能找到各种动物的化石，至少在这些特定地点已经发现了大量的化石。
Now, in a grassland of Lake Ecosystem, we'd expect to find fossils from a variety of animals, and numerous fossils have been found at least at these particular sites.
从非洲和亚洲等地挑选一群巨型动物，把它们引入到与它们现在的家园类似的其他生态系统中，首先从美国开始。
Take a select group of animals, megafauna from places like Africa and Asia, and introduce them into other ecosystems similar to their current homes, beginning in the United States.
植物平衡了生态系统、保护了流域、减缓了侵蚀、缓和了气候，为许多动物物种提供了庇护所。
Plant life balances ecosystems, protects watersheds, mitigates erosion, moderates climate and provides shelter for many animal species.
在脊椎动物中，免疫系统提供了对体内寄生虫的多重防御。
In vertebrates, the immune system provides a multiple defense against internal parasites.
巨噬细胞是在小鼠和其他哺乳动物的免疫系统对细菌等侵入性生物的反应中发挥作用的细胞。
Macrophages are cells that play a role in the response of the immune system of mice and other mammals to invasive organisms such as bacteria.
这对依赖北极生态系统生存的北极野生动物和土著居民提出了独特的挑战。
This raises unique challenges for Arctic wildlife and indigenous people who depend on Arctic ecosystems to survive.
数学模型也揭示了食物网可能是不稳定的，顶级肉食性动物的微小改变会对整个生态系统产生巨大影响。
Mathematical models have also revealed that food webs may be unstable, where small changes of top predators can lead to big effects throughout entire ecosystems.
今天，我想看看哺乳动物的一些交流系统，尤其是灵长类动物，比如猩猩，黑猩猩，大猩猩。
Today, I'd like to look at some communication systems found in mammals, particularly in primates, such as orangutans, chimpanzees, gorillas.
每1美元的鸭票中约有98美分直接转入候鸟保护基金，用于购买湿地和野生动物栖息地，将其纳入国家野生动物保护区系统——这一做法使得土地受到长久的保护。
About 98 cents of every duck stamp dollar goes directly into the Migratory Bird Conservation Fund to purchase wetlands and wildlife habitat for inclusion into the National Wildlife Refuge System—a fact that ensures this land will be protected and available for all generations to come.
这促使她创造了各种设计，从旨在减少即将被杀死的动物所受压力的弧形围栏，到处理病牛、病猪的系统。
This led her to create designs ranging from sweeping curved fences intended to reduce the stress experienced by animals that were going to be killed to systems for handling sick cattle and pigs.
雨林有自己完善的系统来确保自身的生存；高大的树木有枝叶形成的树冠层来保护自身，树冠也保护着矮小的植物以及动物不受暴雨、酷暑及强风的侵扰。
Rainforests have their own perfect system for ensuring their own survival; the tall trees make a canopy of branches and leaves which protect themselves, smaller plants, and the forest animals from heavy rain, intense dry heat from the sun and strong winds.
从应答方面来讲，动物的免疫防御系统又划分为先天性免疫细胞及分子和适应性免疫细胞及分子。
Animal immunizing and defending system is also divided into geneogenous immunizing cells and molecules & adaptive immunizing cells and molecules on response.
我们已经建立了霜冻预警系统，为动物建立了庇护所。
We have set up early warning systems for frosts and shelters for animals.
饲养者可以凭借着本国动物身份证明系统注册，但那完全是自愿的。
Owners can register via the National Animal Identification System, but it is strictly voluntary.
植物没有动物大脑里的那种中枢控制系统。
Plants have no central control systems as in animals' brains.
因此，国家和区域动物疾病监视系统不仅需要预防畜牧生产遭受损失，而且需要减轻对人体健康的威胁。
Hence there is the need for national and regional animal disease surveillance systems to prevent not only losses to livestock production, but to reduce threats to human health as well.
改进公、私营部门动物卫生系统的管理，是应对这一惊人状况最有效的手段。
Improving the governance of animal health systems in both the public and private sector is the most effective response to this alarming situation.
改进公、私营部门动物卫生系统的管理，是应对这一惊人状况最有效的手段。
Improving the governance of animal health systems in both the public and private sector is the most effective response to this alarming situation.
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