有这样一则故事: 很久前,在一条河的两岸各生存着一群羊,它们在绿茵如毯的河岸两边各为群落,繁衍生息。 几年后,人们惊奇地发现,原本是一样壮大的群落,却出现了两种截然不同的景象,河岸东边的羊群个个肥壮,奔跑有力,而河岸西边的羊群个个瘦弱,几乎除了觅食的本能,便没有太多的活力了。 这样两种不同的结果,引起了生物 There is such a story: A long time ago, a group of sheep survived on both sides of a river. They flourished on both sides of the banks of a green carpet, such as the carpet. A few years later, people were surprised to find that originally the same as the expansion of the community, there have been two completely different scenery, the east bank of the river are all fat and powerful, and the flock to the west of the banks of the thin, almost except Foraging instinct, there is not much vitality. Such two different results, causing the creature