Figure 1From: Life cycle evolution: was the eumetazoan ancestor a holopelagic, planktotrophic gastraea?Theories about the origin of the indirect life cycles. The upper row shows the ontogenies of the ancestral organisms, and the lower row shows the ontogenies of the indirect, pelago-benthic organisms with the added life cycle stages indicated in red. The cnidarians have sessile adults instead of creeping adults.Back to article page