You get divided, and a continent's division corresponds to a fork in the evolutionary tree, or you're crafty, and you manage to escape from one to the other and erase that division, or you're living peacefully on each side, and on one side you just go extinct, and you survive on the other side and create a difference.
陆生动物被分开，每一个分开后的大陆板块 对应着进化树的一个分叉， 如果你够厉害，成功地 从一个板块跳到另一个板块，也就是说你消除了这种隔离， 要么你在两边都生活很好， 要么你在一个板块上灭绝了， 要么你在另外的板块活下来，并且发生了一些变化。