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Tropical rainforests are the most biologically diverse of terrestrial biomes. Despite the ecological importance and economic potential of tropical trees, a large fraction of tropical forest tree species lack scientific names, and hundreds of woody plant species in the most intensively studied forest plots remain unidentified. DNA diagnostic tools, including plastid “DNA barcodes” and multilocus genomic markers, can be applied to tropical forest dynamics plots to facilitate taxonomic discovery. Such genetic surveys, as outlined in this article, require expanded herbarium infrastructure and linkages infield ecology, population genetics, and bioinformatics. The fusion of traditional botany and molecular methods will provide baseline data for understanding both the origin and maintenance of tropical plant diversity.
Diatoms are photosynthetic unicellular eukaryotes found in most aquatic environments. They are major players in global biogeochemical cycles, and generate as much oxygen through photosynthesis as terrestrial rainforests do. Insights into their evolutionary origins have been revealed by the whole-genome sequencing of Thalassiosira pseudonana and Phaeodactylum tricornutum. We now know that diatoms contain unusual assortments of genes derived from different sources, including those acquired by horizontal gene transfer from bacteria. These genes confer novel metabolic and signaling capacities that may underlie the extraordinary ecological success of diatoms on Earth today. The availability of a suite of techniques that can be used to monitor and manipulate diatom genes is enhancing our knowledge of their novel characteristics. We highlight these recent developments and illustrate how they are being used to understand different aspects of diatom biology. We also discuss the use of diatoms in commercial applications, such as for nanotechnology and biofuel production.
Demand for land to grow corn for ethanol increased in the United States by 4.9 million hectares between 2005 and 2008, with wide-ranging effects on wildlife, including habitat loss. Depending on how biofuels are made, additional production could have similar impacts. We present a framework for assessing the impacts of biofuels on wildlife, and we use this framework to evaluate the impacts of existing and emerging biofuels feedstocks on grassland wildlife. Meeting the growing demand for biofuels while avoiding negative impacts on wildlife will require either biomass sources that do not require additional land (e.g., wastes, residues, cover crops, algae) or crop production practices that are compatible with wildlife. Diverse native prairie offers a potential approach to bioenergy production (including fuel, electricity, and heat) that is compatible with wildlife. Additional research is required to assess the compatibility of wildlife with different composition, inputs, and harvest management approaches, and to address concerns over prairie yields versus the yields of other biofuel crops.
Apex predators have experienced catastrophic declines throughout the world as a result of human persecution and habitat loss. These collapses in top predator populations are commonly associated with dramatic increases in the abundance of smaller predators. Known as “mesopredator release,” this trophic interaction has been recorded across a range of communities and ecosystems. Mesopredator outbreaks often lead to declining prey populations, sometimes destabilizing communities and driving local extinctions. We present an overview of mesopredator release and illustrate how its underlying concepts can be used to improve predator management in an increasingly fragmented world. We also examine shifts in North American carnivore ranges during the past 200 years and show that 60% of mesopredator ranges have expanded, whereas all apex predator ranges have contracted. The need to understand how best to predict and manage mesopredator release is urgent—mesopredator outbreaks are causing high ecological, economic, and social costs around the world.
Many studies have assessed whether and to what degree students (grade-schoolers to undergraduates), teachers, and the public in general accept and understand evolution. However, very little information has been available about the level of understanding of students pursuing an advanced postgraduate degree in science. The study discussed in this article involved a survey of graduate students from four science colleges at a midsized Canadian university. Encouragingly, the results indicate that graduate students in diverse disciplines exhibit a better understanding of evolutionary concepts than do students at other levels. However, a working knowledge of evolutionary mechanisms may remain elusive, and some misconceptions may persist, even at this advanced level.
Charles Darwin is one of the most revered (and at times reviled) figures in Western history. A great many “facts” about him and his ideas are the stuff of textbook myths, others are inaccuracies spread by antievolutionists, and still others are conventional historical mistakes long corrected but still repeated. I present 10 such misconceptions, and some quick and necessarily incomplete rebuttals. New scholarship is rapidly clearing away some of these myths.