The adaptive significance of life history characters in selectedorders of marine brown maeroalgae

Life history charaeters. which are generally eonsidered to be of eritieal signifteanee in evolution, consist of various pheiiotypie trails eoneerned with growth and reproduetion. Suites ot life history charaeters are frequently referred to as ‘strategies’. These are hypotheses which attempt to explain the adaptive significance of particular suites of charaeters. This paper reviews life history charaeters of species belonging to various orders of brown algae (Phaeophyeeae) and diseusses their possible adaptive, significance, together with the extent to which they are eonsistent with opportunistie, stress tolerant and biotieally eompetent strategies. In general, speeies belonging to the same order have broadly similar suites of life history charaeters and, thus, to some degree they share eomparable adaptive strategies. For example. the Laminariales, Fueales and Durvillaeales inelude a high proportion of biotieally eompetent speeies. many ofthe Dietyotales appear to be stress tolerant, and the Eetoearpales are typieally opportunistie. The two heteromorphie generations of speeies in the Seytosiphonales are viewed as having divergent strategies, the erustose stages showing a greater degree of stress toleranee than the opportunislie ereet stages.