Since the time of Charles Darwin in the 19th century, biologists have recognized that biodiversity increases dramatically from the poles to the equator. For example, there are more tree species in some 50-hectare plots of tropical rainforest than in all of North America! Despite nearly two centuries of inquiry, biologists still do not know why the tropics are so much more diverse than temperate ecosystems. Scientists are now studying the ecological and evolutionary factors that create and maintain biodiversity with renewed urgency because of growing societal concerns about biodiversity conservation.
Dr. Allen is developing and testing new theoretical and statistical approaches to address this question, which involve the mathematical modeling and analysis of DNA sequence data, fossil data, and contemporary biodiversity data. Contrary to conventional wisdom, Dr. Allen's recent work does not support the hypothesis that many different life forms converge at the equator because warm, tropical environments are benign and thereby allow for "comfortable living". Instead, Dr. Allen's research indicates that higher temperatures lead to greater biodiversity because organisms "live faster and die younger" in tropical environments, which leads to higher rates of DNA mutation and faster rates of speciation.
Dr. Allen's research has also yielded the first-ever calculation of the energy required to produce biodiversity. For single-celled planktonic organisms called foraminifera (see illustrations), Dr. Allen calculates that it takes about 100,000,000,000,000,000,000,000 joules of energy to produce a single new species in the world's oceans. This quantity exceeds current annual global fossil fuel consumption by all of humanity. Conservationists have long considered biodiversity to be priceless. Dr. Allen's research suggests, however, that biodiversity does have a price, and that this price is extremely high in terms of energy.