Department of Biology, University of Washington, Seattle, WA 98195, USA.
Proc Natl Acad Sci U S A. 2012 Aug 21;109(34):13686-91. doi: 10.1073/pnas.1202233109. Epub 2012 Aug 7.
From microbes to humans, the success of many organisms is achieved by dividing tasks among specialized group members. The evolution of such division of labor strategies is an important aspect of the major transitions in evolution. As such, identifying specific evolutionary pressures that give rise to group-level division of labor has become a topic of major interest among biologists. To overcome the challenges associated with studying this topic in natural systems, we use actively evolving populations of digital organisms, which provide a unique perspective on the de novo evolution of division of labor in an open-ended system. We provide experimental results that address a fundamental question regarding these selective pressures: Does the ability to improve group efficiency through the reduction of task-switching costs promote the evolution of division of labor? Our results demonstrate that as task-switching costs rise, groups increasingly evolve division of labor strategies. We analyze the mechanisms by which organisms coordinate their roles and discover strategies with striking biological parallels, including communication, spatial patterning, and task-partitioning behaviors. In many cases, under high task-switching costs, individuals cease to be able to perform tasks in isolation, instead requiring the context of other group members. The simultaneous loss of functionality at a lower level and emergence of new functionality at a higher level indicates that task-switching costs may drive both the evolution of division of labor and also the loss of lower-level autonomy, which are both key components of major transitions in evolution.
从微生物到人，许多生物体的成功都是通过将任务分配给专门的群体成员来实现的。这种分工策略的进化是进化的主要转折点的一个重要方面。因此，确定导致群体水平分工的特定进化压力已成为生物学家关注的主要课题。为了克服在自然系统中研究这一课题所面临的挑战，我们使用积极进化的数字生物体群体，这为在开放式系统中从头开始进化分工提供了独特的视角。我们提供的实验结果解决了一个关于这些选择压力的基本问题：通过降低任务转换成本来提高群体效率的能力是否会促进分工的进化？我们的研究结果表明，随着任务转换成本的增加，群体越来越多地进化出分工策略。我们分析了生物体协调其角色的机制，并发现了具有惊人生物学相似性的策略，包括沟通、空间模式和任务划分行为。在许多情况下，在高任务转换成本下，个体将无法独立执行任务，而是需要其他群体成员的背景。较低层次的功能同时丧失和较高层次的新功能的出现表明，任务转换成本可能既推动分工的进化，也推动较低层次自主性的丧失，这两者都是进化的主要转折点的关键组成部分。
