The half-billion-year history of animal evolution is characterized by decreasing rates of background extinction. Earth's increasing habitability for animals could result from several processes: (i) a decrease in the intensity of interactions among species that lead to extinctions; (ii) a decrease in the prevalence or intensity of geological triggers such as flood basalt eruptions and bolide impacts; (iii) a decrease in the sensitivity of animals to environmental disturbance; or (iv) an increase in the strength of stabilizing feedbacks within the climate system and biogeochemical cycles. There is no evidence that the prevalence or intensity of interactions among species or geological extinction triggers have decreased over time. There is, however, evidence from palaeontology, geochemistry and comparative physiology that animals have become more resilient to an environmental change and that the evolution of complex life has, on the whole, strengthened stabilizing feedbacks in the climate system. The differential success of certain phyla and classes appears to result, at least in part, from the anatomical solutions to the evolution of macroscopic size that were arrived at largely during Ediacaran and Cambrian time. Larger-bodied animals, enabled by increased anatomical complexity, were increasingly able to mix the marine sediment and water columns, thus promoting stability in biogeochemical cycles. In addition, body plans that also facilitated ecological differentiation have tended to be associated with lower rates of extinction. In this sense, Cambrian solutions to Cambrian problems have had a lasting impact on the trajectory of complex life and, in turn, fundamental properties of the Earth system.

动物进化的五亿年历史的特点是背景灭绝率不断下降。地球越来越适合动物居住，这可能是由几个过程造成的：（i）物种之间相互作用强度的降低，从而导致灭绝；(ii) 玄武岩溢流喷发和火流星影响等地质触发因素的发生率或强度降低；(iii) 动物对环境干扰的敏感性降低；(iv) 气候系统和生物地球化学循环内稳定反馈的强度增加。没有证据表明物种之间相互作用或地质灭绝触发因素的普遍性或强度随着时间的推移而减少。然而，古生物学、地球化学和比较生理学的证据表明，动物对环境变化的适应能力更强，而且复杂生命的进化总体上增强了气候系统的稳定反馈。某些门和纲的不同成功似乎至少部分是由于在埃迪卡拉纪和寒武纪时期主要达到的宏观尺寸演化的解剖学解决方案造成的。由于解剖结构复杂性的增加，体型较大的动物越来越能够混合海洋沉积物和水柱，从而促进生物地球化学循环的稳定性。此外，也促进生态分化的身体结构往往与较低的灭绝率相关。从这个意义上说，寒武纪问题的解决方案对复杂生命的轨迹产生了持久的影响，进而对地球系统的基本特性产生了持久的影响。