Only one species on earth for millions of years? Why would they eventually break up into other species of animals? Just curious.
2006-09-08 05:53:45 · 3 answers · asked by WhiteHat 6 in Science & Mathematics ➔ Biology
Hmmmm.... could be.
2006-09-08 05:55:39 · answer #1 · answered by Anonymous · 0⤊ 1⤋
Mammals first evolved from one lineage of reptiles, during the Permian Period (299 m.y. - 251 m.y.). Migration to differing environments gave rise to speciallization, but evolved using the same basic "tool set" as the originals.
It is generally agreed on that most early mammals were evolutionary dead ends, and modern mammals are descendants of a fairly small subset of these early mammalian ancestors
2006-09-08 06:21:48 · answer #2 · answered by Susan S 2 · 0⤊ 0⤋
Natural selection and adapting to fill unoccupied niches in nature.
2006-09-08 06:00:45 · answer #3 · answered by Michael B 5 · 0⤊ 0⤋