Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Department of Environmental Sciences, Tel Hai College, Tel-Hai 12208, Israel.
Proc Biol Sci. 2020 Feb 12;287(1920):20192805. doi: 10.1098/rspb.2019.2805. Epub 2020 Feb 5.
Evolutionary transitions in individuality (hereafter, ETIs), such as the transition to multi-cellularity and the transition to social colonies, have been at the centre of evolutionary research, but only few attempts were made to systematically operationalize this concept. Here, we devise a set of four indicators intended to assess the change in complexity during ETIs: system size, inseparability, reproductive specialization and non-reproductive specialization. We then conduct a quantitative comparison across multiple taxa and ETIs. Our analysis reveals that inseparability has a crucial role in the process; it seems irreversible and may mark the point where a group of individuals becomes a new individual at a higher hierarchical level. Interestingly, we find that disparate groups demonstrate a similar pattern of progression along ETIs.
个体进化转变（后文简称 ETIs），如向多细胞生物的转变和向社会群体的转变，一直是进化研究的核心，但很少有尝试系统地操作这个概念。在这里，我们设计了一套四个指标，用于评估 ETIs 期间的复杂性变化：系统大小、不可分割性、生殖专门化和非生殖专门化。然后，我们在多个分类群和 ETIs 中进行了定量比较。我们的分析表明，不可分割性在这个过程中起着关键作用；它似乎是不可逆转的，可能标志着一群个体成为更高层次新个体的转折点。有趣的是，我们发现不同的群体在 ETIs 中表现出相似的进化模式。
