Center for Behavior, Evolution, and Culture

Carl Bergstrom - Information in Biology
2003-10-13 00:00 (America/Los_Angeles)
Carl Bergstrom: University of Washington Dept. of BiologyOver the past 3.5 billion years, biological organisms have evolved to acquire, process, store, and transmit information. How have organisms evolved to handle the same problems with which we are confronted in this so-called Information Age: problems of information storage and processing, problems of transmission and reliability, problems of trust and deception? For all the attention that is directed toward the changing conception of information and its function in our world, remarkably little is known about the broad role of information in biological systems.
In dealing with information, similar strategic problems are faced across levels of organization. Moreover, a similar process – evolution
by natural selection – has generated the solutions that we observe. I argue for the value of a comparative theoretical approach to understanding the problems inherent in information handling, using examples at scales from intracellular regulation to human communication.http://octavia.zoology.washington.edu/signalling/peacock.pdf

Jared Diamond - Environmental fragility: What was special about Easter Island?
2003-10-06 00:00
Jared Diamond: UCLA Dept. of GeographySome societies have suffered environmental collapses in the past (Easter Island, Angkor Wat, Anasazi, Classic Mayaâ€¦), while others have remained intact for thousands of years (Japan, Northwest Europe, Java, Tikopiaâ€¦). Some countries are close to collapse today, while others are not. What makes some societies more fragile than others? Authors variously seek either geographic or cultural explanations. Barry Rolettâ€™s and my recent re-analysis of Easter Island shows the importance of both types of explanations. Analysis of a data-base of 80 Pacific islands whose societies had widely differing outcomes reveals nine geographic variables predisposing towards deforestation. Easter was especially fragile on almost all nine counts. But there were also four cultural factors that contributed. In short, collapses arenâ€™t accidents.

Peter Sozou - Discounting the future: an evolutionary approach to ageing and time-preference behaviour
2003-09-29 00:00
Peter Sozou: London School of EconomicsDiscounting occurs when an immediate benefit is systematically valued more highly than a delayed benefit. This talk is concerned with understanding both the causes and effects of discounting from an evolutionary point of view, as reflected in physiological and behavioural strategies of organisms.
I’ll start by looking at the evolutionary theory of ageing. Extrinsic mortality (together with population growth where applicable) means that immediate reproduction makes a greater contribution to fitness than an equivalent amount of potential reproduction after a delay. This leads to the principle of the diminishing importance of the future. Ageing may be the outcome of a trade-off between short-term fertility and long-term maintenance. I will (briefly) present some new results showing conditions which determine whether an ageing or a non-ageing strategy will be favoured under such a trade-off.
The effects of ageing – declining fertility and increasing mortality – give an organism additional reason to prefer immediate over delayed reproduction in its behavioural time-preference choices. That is, an animal should discount the future not only because of external factors (extrinsic mortality, population growth), but also because of its own evolutionary response to those factors in the form of ageing. By this analysis, ageing is both a consequence and a cause of discounting.
Using this framework, a series of models is developed, making different assumptions about external hazards and biological ageing. With realistic ageing assumptions – increasing mortality and an accelerating rate of fertility decline – the time-preference rate increases in old age. Under an uncertain external hazard rate, young adults should also have relatively high time-preference rates because their (Bayesian) estimate of the external hazard is high. The middle-aged may therefore be the most long-term in their outlook.http://www.bec.ucla.edu/papers/Sozou_9-29-03.pdf

Jessica Lynch Alfaro - Comparative Phylogenomics, Biogeography and Conservation of Neotropical Primates
Jessica Lynch Alfaro: UCLANeotropical primates represent one of the most successful mammalian radiations in the Neotropics, and all living platyrrhine monkeys in Central and South America stem from a single common ancestor from about 22 Ma. Neotropical primates exhibit extreme morphological and behavioral diversity, from the tiny pygmy marmoset to the ape-like muriqui, and they occupy not only rainforest habitats, but dry forests, savannah-like habitats, and high altitude geography in the Andes. However, about 45% of Neotropical primate taxa are now ‘red listed’ as threatened species by the IUCN, and more information is needed to characterize Neotropical primate biodiversity. Fortunately, studies on the phylogenetic relationships and evolutionary history of Neotropical primates have increased dramatically in recent years using collaborative international efforts at data collection and new techniques in genomics and biogeography. Here I present a comparative perspective of Neotropical primate biogeography, elucidating the geographic barriers, geologic events, and biotic factors most important to shape the primate diversity we see today. I also discuss the impact that phylogenomic and biogeographic studies have had on taxonomy and conservation priorities for this important Neotropical group, and consider what behavioral or life history attributes buffer some primates’ extinction risk in the face of anthropogenic change.

Jacinta Beehner -
Jacinta Beehner:
