Where Did the New Life Come from
In 1883 a small volcanic island blew up.It was Krakatoa,west of Java in Sunda Strait.Nothing was left alive except one kind of earthworm.Yet in time plants began to grow again.By 1928 many kinds of animals lived on the island.
Where did the new life come from?The nearest land was almost twelve miles away.Only a few of the new animals could fly or swim so far.The bugs,flies,and spiders were probably carried by the wind.The lizards and rats may have floated there on pieces of driftwood.Snails could have come on the wind or on floating coconuts or driftwood.Tornadoes and hurricanes may also have picked up creatures and dropped them miles away.
These are some examples of“accidental migration”.Such trips have carried many plants and animals to new homes.
新的生命来自何方
1883年,一个小火山岛火山爆发了,这就是巽他海峡中的爪哇岛西部的喀拉喀托火山。除了一种蚯蚓外,一切都死亡了。然而,植物终于又开始生长。到1928年,许多种动物又生活在岛上了。
新的生命来自何方呢?离岛最近的陆地差不多也有12英里之遥。新来的动物中,只有几种能飞行或凫水游这么远的路。臭虫、苍蝇和蜘蛛也许是风刮去的。蜥蜴和老鼠可能是乘一块块浮木漂流到那里的。蜗牛则可能是靠风力,或飘浮在水上的椰子或木头来到岛上的。龙卷风和飓风或许也会卷起动物,并把它们抛到数里以外的地方去。
这些是“偶然迁徙”的几个实例。这样的迁移把许多植物和动物送到了新家。