Frank S A
Department of Ecology and Evolutionary Biology, University of California, Irvine 92717, USA.
Nature. 1995 Oct 12;377(6549):520-2. doi: 10.1038/377520a0.
Evolutionary theory has not explained how competition among lower level units is suppressed in the formation of higher-level evolutionary units. For example, the key problem of early evolution is small, individual replicators formed cooperative groups of sufficient complexity to allow accurate copying of the genetic material. The puzzle is why parasites did not subvert the formation of cells by obtaining benefits from the group without contributing to shared traits that enhance reproduction. These parasites would outcompete other replicators within the cell, disrupting reproductive fairness among subunits and destroying the functional coherence of the group. A similar problem arose at a later evolutionary stage with the orderly mendelian segregation of subunits (chromosomes) within cells, and reproductive fairness continued to be a problem in the evolution of insect and human societies. Here I present a simple model to show how reproductive fairness evolves among subunits to create functional coherence and higher-level units. Self-restraint, which evolves according to the kin-selection coefficient of relatedness, is not sufficient: mutual policing and enforcement of reproductive fairness are also required for the evolution of increasing social complexity.
进化理论尚未解释在更高层次进化单元的形成过程中，较低层次单元之间的竞争是如何被抑制的。例如，早期进化的关键问题是，小型的个体复制子形成了足够复杂的合作群体，以实现遗传物质的精确复制。令人困惑的是，为什么寄生虫没有通过从群体中获取利益却不为增强繁殖的共享特征做出贡献来破坏细胞的形成。这些寄生虫会在细胞内胜过其他复制子，破坏亚单元之间的繁殖公平，并破坏群体的功能连贯性。在后来的进化阶段，随着细胞内亚单元（染色体）的孟德尔式有序分离，也出现了类似的问题，而且繁殖公平在昆虫和人类社会的进化中仍然是一个问题。在此，我提出一个简单的模型，以展示亚单元之间的繁殖公平是如何进化，从而创造出功能连贯性和更高层次的单元的。根据亲缘关系的亲缘选择系数进化而来的自我约束是不够的：对于日益增加的社会复杂性的进化，还需要相互监督和对繁殖公平的执行。
