BIOLOGY 152 Lecture Notes - Lecture 35: Semibalanus Balanoides, Trophic Cascade, Apex Predator
2 May 2016
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Document Summary
Bio152 lecture 35 ecological disruptions and trophic cascades. Barnacles: the barnacle life cycle is shown below, testing the hypothesis of exclusion, field experiment on barnacles. Two species of barnacles: chthamalus stella only in upper intertidal, balanus balanoides only in lower intertidal. Is the difference between species in zone occurrence due to competition: remove balanus, chthalamus thrives in lower zone, remove chthalamus, balanus does not invade upper zone. Between-species competition: common interaction, but extensive niche overlap (direct competition) infrequently observed, most likely to see it when species newly introduced or when other factors limit population of better competitor. Instead, known mostly by its consequences (outcomes: outcomes, exclusion of one competitor. Extinction of one competitor: resource partitioning, character displacement - character needed to partition the resource, outcome can vary under different conditions. Ecological disruptions: we can look at the disruptions and how we can disrupt a species, species interactions in communities, connections often revealed by unexpected outcomes when communities are disrupted.
