Which earlier ideas about evolution were proposed by Erasmus Darwin?

Erasmus Darwin, the grandfather of Charles Darwin, proposed early evolutionary ideas that were rooted in a materialist perspective, rejecting the biblical chronology of his time.1

In his work Zoonomia (1794–96), he suggested that over vast periods of time, all warm-blooded animals might have descended from a single "living filament". He proposed that this ancestral life form possessed an inherent capacity to improve through its own activity and to pass those acquired improvements down to its descendants through generation.1

Later, in his poem The Temple of Nature (1803), he expanded on these concepts, presenting human achievements as the culmination of nature's innate progressive forces. While he did not identify the mechanism of natural selection—which his grandson would later famously articulate—Erasmus Darwin’s work was significant for its focus on the transformation of species and the influence of nature’s forces, even if his ideas were often expressed through ornate, didactic poetry that eventually fell out of favor.1