Oct 29 2009

Oct 29 2009 - Species Interactions I, 29 Oct 2009 R e a d...

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Species Interactions I, 29 Oct 2009 Readings Levinton: Chapter 3, pp 46-61; 68-78 Levinton: Chapter 14, pp 355-381 Levinton: Chapter 15, pp 418-455 1998. Killer whale predation on sea otters linking oceanic and nearshore ecosystems. Science 282:473-476. Biology 18: R547-551 Knowlton, N. 2006. Coral Reefs. Current Biology 18: R18-R21. Fundamental question in ecology: What controls the distribution and abundance of organisms? Abiotic factors – interactions with the environment Biotic factors – interactions with other organisms Species Interactions: primary types 1) predation - benefits one species (+), negative effects on another species (-) 2) competition - negative effects on both species (- ,-) 3) mutualism - positive effects on both species (+,+) Marine environments have been fertile areas for research in species interactions Species zonation is especially apparent in the intertidal - Easily observed and quantified - Common on all shores (sandy shores, mangroves, etc.) but especially obvious on rocky shores - Zonation is often a tradeoff between biotic and abiotic factors Rocky Intertidal Communities: One of the most well-studied marine systems Study of these communities has played a key role in understanding nature of species interactions in general and their effects on community structure (not just for marine systems). Why? 1) Intertidal is largely a 2-dimensional system 2) Physical factors are important, especially in the upper intertidal 3) Key resource is space 4) Relatively easy to manipulate key resource to test for interactions
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Causes of zonation in the rocky intertidal 1) Physiological tolerance 2) Larval and adult habitat preferences 3) Competition 4) Predation Barnacles are especially well-studied Crustaceans (Arthropods) Eggs released into water at hatching Larval dispersal stages Larvae settle from plankton onto rocks (appropriate substrate needed) Build calcareous test Lie on “back” with appendages protruding from test Feed by capturing plankton with appendages Small species reach sexual maturity in 2-3 months Barnacle tests 1- Allow them to attach permanently to rocks hold on in surge if test is dislodged they do not survive must have open space to settle 2 - Plates of test can be closed - prevents drying out- permits them to live high in the intertidal where many other marine organisms cannot survive - provides protection from predators - Fundamental EXPERIMENTAL studies on factors controlling intertidal zonation were conducted in middle of last century by Joseph Connell in Scotland (UCSB) - In order to understand patterns of zonation that had been well known, Connell performed a series of carefully controlled experiments to document the interactions of species with their environment, competitors, and predators - His landmark studies have been expanded upon by researchers working in other areas and other habitats
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This note was uploaded on 02/23/2010 for the course BIEB BIEB 132 taught by Professor Hastings during the Fall '09 term at UCSD.

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Oct 29 2009 - Species Interactions I, 29 Oct 2009 R e a d...

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