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In the Light of Evolution: Volume II—Biodiversity and Extinction
niche conservatism for the future of plant biodiversity in the face of global climate change and habitat fragmentation.
In a somewhat similar vein, Jonathan Davies and colleagues associated with the Andy Purvis group show in Chapter 14 how a phylogenetic modeling approach can help to identify mammalian taxa whose intrinsic biology might lend them especially vulnerable to environmental pressures. They begin by combining phylogenetic information from a recently completed Tree of Life for mammals with ecological, life history, and geographic data to examine the origins and current distributions of mammalian biodiversity. Results from the analysis indicate that evolutionary cradles of origin have shifted over time, and that extinction risks vary according to the type of mammal (e.g., large-bodied versus small-bodied) and also to spatial and temporal differences (often region-specific) in threat intensity. The authors discuss ramifications of such phylogenetic findings for the near- and long-term future of mammalian biodiversity, including how alternative criteria (different “currencies of conservation”) might be used in setting preservation priorities.
Before the mid-20th century, scientific analyses of biodiversity rested on appraisals of organismal phenotypes. That situation changed dramatically when molecular techniques were introduced that permitted direct assays of genotypes. The molecular revolution in evolutionary biology has provided powerful tools for biodiversity assessments ranging from species identifications and phylogeny reconstructions to genetic dissections of ontogeny. Projecting forward, in Chapter 15 John Avise describes three opportunities for the field of biodiversity genetics that seem not to have been widely appreciated or discussed: use information from the emerging phylogenetic Tree of Life to erect the first-ever universally standardized scheme of biological classification; identify biogeographic hotspots and centers of origin (including those tracing to the late Tertiary) for various extant biotas; and engage in educational outreach by conveying to students and the public a sense of wonder and appreciation for the marvelous workings of nature, many of which are being revealed for the first time by genetic appraisals. Capitalizing on these opportunities should be instructive for basic science and also helpful in conservation efforts.
In Chapter 16, Michael Novacek expands on the public-outreach mission for conservation biology by emphasizing the need to awaken a broad audience to the ongoing biodiversity crisis. Despite the urgency of current environmental problems, and committed efforts (albeit by relatively small segments of society) over the past 20 years to find solutions, national and international responses to date have been slow to materialize and inadequate to steward global biodiversity through the crucial 21st century. One major reason is the general lack of understanding and engagement on biodiversity issues by the public, which in polls typically ranks environ-