Emergence of Ectocarpus as a Model System to Study the Evolution of Complex Multicellularity in the Brown Algae

Abstract

The evolution of multicellularity provided new ways for biological systems to increase in complexity Complexity . However, although high levels of complexity have indeed been attained in several multicellular lineages, natural selection does not necessarily favor complex biological systems. Why and how, then, has complexity increased in some lineages? We argue that the volvocine green algae Green algae (Volvox and its relatives) are a uniquely valuable model system for understanding the evolution of multicellular complexity. Using a general framework for the evolution of complexity, we discuss the various levels of morphological and developmental complexity achieved in this group, and consider both the why and the how underlying the changes in complexity levels that took place in this group.