Complex sentence: Charles Darwin proposed the idea of stasis in On the Origin of Species suggesting that species spend the majority of their evolutionary lifespan in the same form, having undergone very little morphological or genetic change.
Split into simpler sentences: Charles Darwin proposed the idea of stasis in his book, "On the Origin of Species". He suggested that species spend the majority of their evolutionary lifespan in the same form, having undergone very little morphological or genetic change.