2007): Contributions of genomics to life-history theory

• Main Author: Derek A Roff
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Pacific; Atlantic salmon; Newfoundland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1084.147; http://aerg.canberra.edu.au/library/sex_general/2007_Roff_genomics_life-history_theory.pdf

Evolution proceeds because of variation in fitness, and directly contributing to this fitness are life-history traits, such as age of maturity, growth rate, fecundity and survival. Other traits contribute indirectly (for example, in most invertebrates, plants and some small mammals, fecundity increases with body size) and are classified as morphological, physiological or behavioural traits. Variation in life-history traits among species can be extreme, as shown by variation in age at maturity and allocation to reproduction. Some species mature within a year of birth and allocate up to 50% of their body mass to reproduction, whereas others take several decades before reproducing and allocate just a few percent of their body mass to each reproductive episode. In the extreme, species such as Pacific salmon reproduce once and die, whereas related species such as Atlantic salmon undergo repeated bouts of reproduction. Even within a single species there is large variation; for example, the flatfish, Hippoglossus hippoglossus, matures at an age of 3 years and a length of 20 cm in Scotland, whereas in Newfoundland the same species does not mature until an age of 15 years and a length of 40 cm. Furthermore, the Scottish fish live to a maximum age of 6 years, but the Newfoundland fish live beyond 20 years 1 . The purview of life-history theory and analysis is this variation in life-history traits, with a central aim of producing a conceptual, mathematical and biological framework in which the evolution of the diversity in life histories both in and among species can be understood. So, life-history theory seeks to produce both mathematical and biological models for the evolution of life-history variation . For example, in many species, fecundity increases with body size, which is achieved by extending the period of growth; on the other hand, the probability of surviving to reproduce will decrease as the time taken to reach maturity is increased. Therefore, there is a trade-off between fecundity and survival that is ...