When changing worlds make every lineage strain
Small inherited differences meet the light
Those favored persist, accumulate, remain
While rare forms fade from competition's sight

No single hand directs the next trial
Selection keeps what proves of use, not creed
Small differences accumulate awhile
When inherited gains improve success and breed

A common frame persists in altered grace
Though barriers divide the living space
In fossils, embryos, remnants, we trace
The history selection cannot erase

So judge each form as history made whole
Not as a blueprint: descent selects its role