BOX 1. LIFE HISTORY STRATEGIES
Are carrots (Daucus carota ) similar to blue ringed octopuses (Hapalochlaena lunulata )? They both start life small, grow fast but few survive to adulthood, produce many offspring in one breeding event at around 1 years old, and are semelparous . In contrast, humans (Homo sapiens sapiens ) and blue whales (Balaenoptera musculus ) grow slowly, mature late but are likely to survive to adulthood, usually produce one offspring every 2-3 years and have remarkably similar lifespans: the oldest known living human, Jeanne Calment, reached 122 years of age, and blue whales may live up to 110 [64]. The sacred fig tree (Ficus religiosa ) and giant barrel sponge (Xestospongia muta ) are like carrots and blue ringed octopuses in that they start life small, are unlikely to survive to adulthood and, once mature, produce many offspring. Xestospongia muta and F. religiosa are also like humans and blue whales, however, as they are iteroparous over long lifetimes: one sacred fig “Jaya Sri Maha Bohi” in Sri Lanka is the oldest known human-planted tree, which at around 2,300 years old is similar in age to the oldest known Caribbean giant barrel sponge [65].
Whilst distantly-related organisms may share similar life history strategies, closely-related organisms can show remarkably different life histories. The Dasyuridae family, to which the Tasmanian devil (Sarcophilus harrisii ) belongs, is one of the most diverse marsupial families [66], with dasyurid species showing different life history strategies, despite being closely related. Maturity occurs at ~11 months but, while in some species all individuals die by 12 months old following a single synchronous mating, others reproduce many times annually and live for several years [67] . Plant life history strategies are often even more labile than animal strategies: pine trees (Pinus spp.) vary vastly in lifespan, despite having similar morphology and physiology: the Virginia pine (P. virginiana ) rarely lives over 150 years [68], whereas bristlecone pine (P. longaeva ) hold the record of non-clonal longevity, at 4,850 year old [69]. Selection for varying longevities in pines may be a result of the differing fire environments [70].
The Tree of Life abounds with examples of distantly related organisms sharing convergent life history strategies, despite divergent body size and lifestyle, and vice versa . Evolutionary ecologists seek to understand, across broad taxonomic groups, how and why diverse life history strategies, such as those exemplified here, are distributed across phylogenies, space, and time.