來自 Hong Kong
回復 #3 寒武紀 的帖子
So far, only female elephant lose their tusk and the male still have their teeth possibly because of sexual selection/ the gene for losing tusk is X/Y chromosome-linked. But well, what evolutionary biology taught me the most is that nothing is permanent and every species/ individual will eventually die out one day. Just like nobody will expect dinosaurs to lose teeth and soar to sky nor dominant reptiles will disappear sometime... it just gives me senses of humbleness and respect to nature as human are so insignificant.