Modularity and network motifs are fundamental features of biological networks, yet their evolutionary origins remain unclear. This study proposes that modularly varying environmental goals can lead to the spontaneous evolution of modular network structures and network motifs. Using evolutionary algorithms, the researchers evolved networks under changing goals that required different combinations of subgoals. The results showed that such "modularly varying goals" led to the spontaneous evolution of modular structures and network motifs, allowing networks to rapidly adapt to each goal. In contrast, fixed-goal evolution typically produced nonmodular networks. The study also found that networks evolved under modularly varying goals exhibited more pronounced network motifs, such as feed-forward loops and diamonds, compared to those under fixed goals. These findings suggest that modularly varying goals may play a key role in promoting structural simplicity in biological networks and could inform the design of more efficient engineered systems. The study highlights the importance of environmental variation in shaping network architecture and suggests that biological evolution in changing environments may rely on modular structures to adapt to new challenges. The results also have implications for understanding how modularity and network motifs emerge in biological systems, as well as for improving the design of artificial systems through evolutionary methods.Modularity and network motifs are fundamental features of biological networks, yet their evolutionary origins remain unclear. This study proposes that modularly varying environmental goals can lead to the spontaneous evolution of modular network structures and network motifs. Using evolutionary algorithms, the researchers evolved networks under changing goals that required different combinations of subgoals. The results showed that such "modularly varying goals" led to the spontaneous evolution of modular structures and network motifs, allowing networks to rapidly adapt to each goal. In contrast, fixed-goal evolution typically produced nonmodular networks. The study also found that networks evolved under modularly varying goals exhibited more pronounced network motifs, such as feed-forward loops and diamonds, compared to those under fixed goals. These findings suggest that modularly varying goals may play a key role in promoting structural simplicity in biological networks and could inform the design of more efficient engineered systems. The study highlights the importance of environmental variation in shaping network architecture and suggests that biological evolution in changing environments may rely on modular structures to adapt to new challenges. The results also have implications for understanding how modularity and network motifs emerge in biological systems, as well as for improving the design of artificial systems through evolutionary methods.