The seven great questions of systematic biology: An essential foundation for conservation and the sustainable use of biodiversity

The three missions of Syslematics Agenda 2000 (SA2000)-to inventory Earth's species, to understand their relationships, and to use the latter to create predictive information systems-define an agenda of research for systmatic biology. The recognition that systematic knowledge underpins biological knowledge in general, and applied biology in particular, has resulted in an amazing growth in systematics over the past decade. Increasingly, systematics is being used to solve societal problems. This paper describes seven great questions within systematics and discusses their relevance for, and contribution to, conserving and sustainably using biodiversity. These questions fall into four broad categories: Questions about diversity: What is a species? and How many species are there? Questions about phylogeny: What is the Tree of Life? and What has been the history of character transformation? Questions about biogeography: Where are Earth's species distributed? and How have species distributions changed over time? and Questions about phyloinformatics: How is phylogenetic history predictive?.