资源概述
[01.22][转贴][美国][纪录][PBS.性的本质5/6][DVDRip/694M][英语/无字]
电影名称：Coming Out - Coming Out
资源名称：[01.22][转贴][美国][纪录][PBS.性的本质5/6][DVDRip/694M][英语/无字]
电影格式：AVI
电影大小：700M
下载次数：84
导演 ：未知
主演 ：凯瑟琳・泽塔琼斯
类型 ：喜剧片 剧情片
地区 ：英国 美国
语言 ：英语
电影介绍 ：... [详细介绍] [相关资源]
资源名称：[01.22][转贴][美国][纪录][PBS.性的本质5/6][DVDRip/694M][英语/无字]
电影格式：AVI
电影大小：700M
下载次数：84
导演 ：未知
主演 ：凯瑟琳・泽塔琼斯
类型 ：喜剧片 剧情片
地区 ：英国 美国
语言 ：英语
电影介绍 ：... [详细介绍] [相关资源]
电影资源介绍
【类 型】：自然/动物
【集 数】：共六集
【影片长度】：6x55mins
【字 幕】：无
【服 务 器】：DonkeyServer NO2 or DonkeyServer NO1
【供源状况】：非自己供源
【视频编码】：XviD
【视频比率】：1660kb/s
【屏幕尺寸】：640x480
【纵 横 比】：4:3
【音频编码】：MP3
【音频比率】：128kb/s
【声 道】：2
【文件大小】：6x700 MB
【压缩制作】：JumpinS
PBS The Nature of Sex [性的本质]
1 最初的本能
2 时间的地点
3 性与合同
4 人与动物
5 制造奇迹
6 婴儿的本质
１
All nature's creatures," the British novelist Graham Swift once wrote, "join to express nature's purpose." And that purpose is illustrated in delightful and sometimes dizzying detail in NATURE's THE NATURE OF SEX. As Part 1: THE PRIMAL INSTINCT shows, birds, bees, and even barnacles and naked mole rats are driven to join forces to reproduce and pass along their genes to the next generation.
As THE PRIMAL INSTINCT illustrates, sex lives comes in many varieties. Some animals mate for life, while others may spend just a few frenzied seconds with their partner. In some cases, the dad takes care of the kids, while in others the mom does all the work. And in many households, the newborns are left to fend for themselves, and will never meet their parents.
Whatever the household arrangements, however, the reproductive strategy that biologists have dubbed "sex" -- in which two individuals combine their genes in an offspring, with each parent typically contributing half of the genetic material -- offers advantages. Most of all, sex assures variety. Every newborn produced by sex carries a unique set of genes that may give them a survival advantage in a changing environment. Slightly longer legs could prove the difference between outrunning a predator and becoming just another meal. And a slightly heavier coat of fur, or a thicker layer of fat, may enable an animal to survive a winter that brings a cold end to others. Variety not only brings spice to life, it seems, but is also a key to survival.
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Not all organisms need sex to multiply, however. Bacteria, for instance, survive just fine by dividing into two genetically identical copies. Similarly, some creatures -- such as the whiptail lizards and aphids featured on THE NATURE OF SEX -- can produce genetically identical clones without the benefit of a partner. But these identical offspring can be much more vulnerable to disease and changing conditions than more mixed breeds. That's why sex, in all its shapes and forms, has proved so successful a reproductive strategy.
Despite its central place in all of our lives, sex remains an often mysterious and poorly understood primal impulse. Researchers are still trying to understand how mates choose each other. Sometimes, the signs of a winner are obvious, such as the sleek coat or colorful plumage that signal good health. But other attractions are more subtle. Only female fiddler crabs, for instance, may ever know if it's the size of a male's waving, outsized claw -- or something else -- that proves so seductive.
２
There is nothing more romantic than a moonlit night. So goes many a love song. But for animals from bat rays to wriggling, seagoing palolo worms, the moon is more than a romantic backdrop -- it's a key signal that the time has come to mate.
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Such sexual signals are the focus of A TIME AND A PLACE, Part 2 of NATURE's THE NATURE OF SEX. From the changing phases of the moon to subtle chemical surges, the program outlines the many cues that trigger sexual activity. Indeed, without these landmarks, many animals would send their newborns into the world at the wrong place and wrong time, with little chance of survival.
Consider the Pacific grunion, for instance. Each spring, millions of these little fish fling themselves up onto Pacific beaches to deposit their eggs in the wet sand. But they don't choose just any night for sex. They ride the spring tide, one of the highest tides of the year, when the moon's pull is the strongest. The choice ensures that there will be enough big waves to get back to the ocean -- and that their eggs will be high enough on the beach to be out of reach of scavenging fish. Arrive a few days early or late, and both fish and eggs will perish.
The moon, however, isn't the only sexual timepiece. The sun is also an important trigger. Many mammals become amorous during the lengthening days of spring -- a sign that warm weather is coming, and with it adequate food supplies for their offspring. But for other animals, rain is the most important romantic event. Darkening skies and heavy drops, particularly in the arid plains of Africa, mean that there will soon be enough grass to feed young gazelle and other browsing animals. Not surprisingly, predators such as jackals time their births to arrive at the same time, using the easily captured baby browsers as food for their own young.
Other signals are produced by the animals themselves. Many insects and mammals, for instance, produce chemicals called pheromones, subtle perfumes used to attract the opposite sex. Others change color, shape, or grow special body parts, such as sharp, curled horns, to signal that they are ready to reproduce. Indeed, few sights are more impressive than a bird in colorful breeding plumage, or a fish that has turned as bright as a neon sign to attract a mate. Now, all they need is a nice, romantic, moonlit night . . .
３
Every year, millions of brides and grooms promise to love and care for each other 'till death do they part. It's a profound promise. But marriage is also just one of the natural world's many mating arrangements, as THE SEX CONTRACT, Part 3 of NATURE's THE NATURE OF SEX shows. Throughout nature, males and females negotiate a wide range of carefully made plans for conceiving and raising offspring.
Indeed, monogamy -- two partners staying sexually faithful to one another -- is one of the rarest kinds of sex contracts.
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Overall, less than 3% of mammal and bird species practice monogamy, and in many of those species, cheating or alternative arrangements is common. Men in some cultures, for instance, have many wives. In others, many men share a single wife. A bird called the Jacana, or Lily Trotter, has a similar sex contract. A single female will have four or five male partners, each carefully caring for eggs laid by the female.
Still other creatures carry this idea to an extreme. African mole rats and termites, for instance, live in underground colonies with a single queen that produces all of the offspring in the colony.
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As a result, almost all of the colony's inhabitants are brother and sister. Male elephant seals, in contrast, play king, ruling over a harem that includes every female on a long stretch of beach.
These arrangements, however different, have the same goal: increasing the number of offspring carrying the parents' genes -- or, in the case of termites, the common genes of the entire colony. And in each case, the contracting partners work together for the common goal: the survival of a new generation.
