Practice question

Charles Darwin correspondence with Joseph Hooker in 1879 lamented abrupt appearance and rapid diversification of flowering plants in Cretaceous fossil record contradicting gradualistic expectation, calling it abominable mystery perplexing evolutionary theory. Mesozoic floras previously dominated by ferns, cycads, conifers were swiftly replaced by angiosperm leaves, flowers and fruits documented in early Cretaceous sediments. Modern explanations invoke co-evolution with insect pollinators, evolution of closed carpel preventing selfing, efficient vessels and fast life cycles herbaceous habit. Green revolution term describes twentieth-century agricultural improvements; adaptive radiation describes pattern but historical phrase specifically identifies angiosperm fossil tempo and diversification explosive nature.