Why leaves of a rowan-tree, some parasites from guts and .... teeth are similar? Because they have similar inventive answer to similar challenge –SEGMENTTION. Segmentation improves the flexibility, adaptability and reliability of a system.
Segmentation involves weakening the connections between elements, changing the parameters of links between elements, splitting a system into independent parts, making a system dismountable, or by making a continuous process discrete (breaking a task or activity into smaller parts that are easier to solve or deal with).
Can something be adaptable staying the same? Now you can see that, it can: “Divide et impera” - use the inventive principle of № 1 SEGMENTATION