Stebbins and Edgar Anderson wrote a paper in 1954 on the importance of hybridization in adapting to new environments. They proposed novel adaptations would facilitate the invasion of habitats not utilized previously by either parent and that novel adaptations may facilitate the formation of stabilized hybrid species. Following this paper, Stebbins developed the first model of adaptive radiation. He proposed that a high degree of genetic variability was necessary for major evolutionary advances, that because of slow mutation rates, genetic recombination was the most likely source of this variation, and that variation could be maximised though hybridization. As of 2006, research is ongoing regarding whether hybridization is an accidental consequence of evolution or if it is necessary for the creation and evolution of plant species; it has been argued that contemporary studies are part of an intellectual lineage that started with the work of Stebbins and Anderson.