首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
A small number of adult chimpanzees were released on Ossabaw Island, Georgia, in order to evaluate the feasibility of establishing a free-ranging reproductive colony of chimpanzees in a semitropical North American climate. First, three females and one male were released in June 1972. Following the unexpected deaths of two of these females, four more females were added. Except for one newborn that was removed from the colony, the chimpanzee colony remained intact, and was still in existence as of February 1975. Preparation for and maintenance of the chimpanzees is described. Behavioral adaptations to the environment, and some aspects of chimpanzee social behavior are reported. The potential importance of colonies such as this, for reducing over-exploitation of naturally occurring primate populations is discussed. The financial support of Yerkes Regional Primate Research Center, Emory University, Atlanta, Georgia, and The Pennsylvania State University, Department of Poultry Science, University Park, Pennsylvania, permitted us to make these observations. Funding for planning and construction of the island facilities, and relocation and maintenance of the chimpanzees was provided by a National Institutes of Health grant toGeoffery Bourne, Director of the Center.  相似文献   

5.
6.
7.
8.
An increase in solar ultraviolet-B (UVB) radiation reaching the earth's surface is an important consequence of stratospheric ozone depletion. UVB has important effects on human health, both beneficial and harmful. Recent research has found that solar UVB reduces the risk of over 20 types of cancer, respiratory diseases caused by viruses, autoimmune diseases, and, likely, several other diseases, in addition to the well-known effects on bone diseases. On the other hand, solar UVB is an important risk factor for non-melanoma skin cancer and cataracts. Human epidemiological studies have provided evidence that solar UVA may be a more important risk factor for melanoma than UVB. If this result is correct, melanoma risk is not related to ozone depletion. We consider the net effect of solar UVB on human health to be beneficial at or near current levels.  相似文献   

9.
10.
11.
12.
13.
14.
The reproductive systems of fourCardamine species were compared.C. flexuosa ssp.flexuosa, a self-pollinated winter annual in fallow paddy fields, produces numerous small seeds.C. flexuosa ssp.fallax, a self-pollinated year-long annual in gardens and roadsides, also produces many small seeds.C. impatiens, a self-pollinated annual in forest margins, similarly produces numerous small seeds.C. scutata is a self-pollinated perennial in ill-drained paddy fields and creeks; its vegetative reproduction is not predominant, and it produces relatively many seeds.C. lyrata, a cross-pollinated perennial with self-incompatibility in ill-drained paddy fields and creeks, produces fewer and heavier seeds, but it does produce many ramets. Moreover, in seed-dispersal mechanisms and germination behavior of fourCardamine species several adaptive characteristics to their habitats are found. These observations on the reproductive systems of fourCardamine species apparently present different characteristics of life-history strategy for each of them.  相似文献   

15.
16.
17.
18.
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号