Sentence:  No one has ever tabulated the number or percentage of non-trending <WSD>clades</WSD> within larger monophyletic groups. The concept of a non-trending <WSD>clade</WSD> — the higher level analog of a species in stasis — has never been explicitly formulated at all. If only one percent of <WSD>clades</WSD> exhibited sustained trends, we would still focus our attention upon this tiny minority in telling our favored version of the story of life's history. 
Meaning of the word marked with <WSD> tags:  A group of animals or other organisms derived from a common ancestor species.