The first animals arise when marine protoctists curtail reproduction in favor of specialization. They are very small, with only soft-body parts, so they may swim with their protoctist cousins for millions of years before circumstances are favorable for their preservation in the fossil record.
University of Montana--Missoula. Environmental Studies Program
© 1997 Stiftung Drittes Millennium
Digital File Format
Digital Image Number
Liebes, Sid; Mittelstadt, Laurie; Waugh, Barbara; and Brynes, Lois, "Panel 50: Animals Arise" (1997). A Walk Through Time - From Stardust To Us. 50.