1 Dispersal transport or movement of organisms typically between place of birth Dispersal Behavior and Biotic Interactions and place of reproduction a Examples of dispersal limitation Gypsy moth o Native of Eurasia o Inadvertently introduced to Boston spread across most of the northeastern US o Survived in non native site o Limited dispersal abilities barrier Atlantic Ocean California sea otter o Native to northwest coast of North America cold waters o Captured for fur absent in waters of northwestern California in 1914 o Limited time for dispersal ultimate cause predation hunting Shiny cowbird o 1900 limited to northern South America o moved up north from island to island o absent in South Florida in 2000 Limited time for dispersal o Caused by habitat change Cowbirds like grasslands islands were volcanic and humans moved onto grassy areas b Dispersal scale and gene flow Touch me not Impatiens capensis example o Dispersal distance varies between populations Seed pods pop and spread up to 1 meter Others drop seeds below parent plant distance is millimeters o Selective environments o Exhibits local adaptation on 10 cm scale c Colonization and extinction Dispersal ability Taxon cycles of island forms o Stage 1 expansion EX shiny cowbird expansion o Stage 2 local adaptaion and local extinction EX House Wren Occurs on all lesser Antilles islands except two killed by volcanos local extinction Species slightly different on each island local adaptation o Stage 3 Widespread extinction EX Adelaides Warbler Occurs on two lesser Antilles islands Substantial local adaptaion Cowbirds are brood parasites lay eggs in nests of other species 1 Cowbirds develop faster than warblers cowbirds get more food 2 Female cowbirds typically removes one of host s eggs No evolutionary history of brood parasitism 1 Extinction 2 Develops defenses 2 Habitat Selection behavioral choice of whether or not to live in certain places a EX Anopheles mosquitoes Observed in southern India mosquitos bred in short rice fields and not in taller stemmed rice fields Female mosquitos flew over both tall and short rice fields no difference in hatching life biotic factors and abiotic factors were suitable Tall rice stems bend and may limit access to water level possibly why female mosquitos avoided them b EX palm warblers Breed in spruce bogs Canada and northern US Migrate to sand dunes fields brushy areas Winter near palm dominated areas Choosy about seasonal habitat c Habitat selection as an evolved response Directional selection for mosquitos to choose short rather than tall rice fields can result in evolution 3 Biotic interactions that limit distributions a Predation EX common mussel o Studied in open ocean and in Lough Ine o Abundant on coast rarer in Ine o Transplant experiment treatment individuals didn t survive may have been a predator o Transplant and exposure experiment treatment group covered with cage to prevent predation group survived o Mussels occur on steep rocky slopes and where freshwater enters Ine Crab predators could not climb slopes and are sensitive to freshwater with low salinity Large body size in Ine due to low wave action feed more efficiently o Small body size on coast due to high wave action can t feed as efficiently EX Desmognathus salamanders o N Dusky salamanders and Mt Dusky salamanders studied by Nelson Hairston Sr o Salamanders occur in zones of ravine N Dusky occurs in streams and stream banks Mt Dusky occurs on slopes of ravine o Predation caused zonation o Removed all N Dusky s Mt Dusky occupied streams and stream banks banks Preferred habitat for both streams and stream N Dusky s excluded Mt Dusky s from preferred habitat by predation b Disease and parasites EX chestnut blight o Limited distribution by Chestnut trees o Inadvertent transplant experiment EX rabbits and myxoma virus in Australia o Rabbits are herbivores breed a lot in right conditions o Researchers isolated myxoma virus from rabbits in South America and infected Australian rabbits with virus o Nearly all rabbits died disease limited distribution o Limited dispersal caused lack of virus in Australia c Competition EX allopathy and black walnut EX Barnacles o Allopathy ecological interaction where organisms use chemicals to hinder other species o Black walnut produces hydroxyjuglone in seed husks o Hydroxyjuglone is water soluble gets hydrolyzed in rain becomes juglone which is toxic o Juglone concentrates in soil prevents other species from growing because juglone is toxic interference competition o Filter feeders Arthropods o Studied in Scotland by Connell o Observed zonation of Balanus and Chthamalus barnacles o Balanus larva and Chthamalus larve in upper middle and lower parts of intertidal o Balanus adults in upper middle to lower intertidal o Chthamalus adults in upper to upper middle intertidal o Transplanted Chthamalus to Balanus zone didn t survive because Balanus overgrew or undergrew Chthamalus o Transplant removal removed Balanus and transplanted Chthamalus survived factors were suitable o Reciprocal Balanus didn t survive in upper intertidal desiccation dried out o Balanus is superior space competitior space is a limited o Moved Chthamalus to upper upper intertidal didn t survive chemical factor water o Predator limited Balanus from being in lower lower o Chthamalus can withstand exposure without water has resource intertidal adapted