GGR305H1 Lecture Notes - Lecture 2: Seed Dispersal, Propagule, Island
Document Summary
Island arcs at subduction zones; depends on immigration via long-distance dispersal. Island chains over hotspots; depends on immigration vis long-distance dispersal. Movement of propagules away from a parent. Dispersalists; (darwin and wallace) suggested that species disjunction were explained by dispersal. Propagule: the unit necessary to found a new colony. Disjunction: the distribution of taxa that is widely divided/ separated by land ocean bodies. Ability to move long distances (flying, swimming, walking) Most animals ( birds bats, migratory species especially adept) Concentrated near point of origin ( exponential decline) Some species are better than others example birds. Biogeography realms and the range limits of species within them reflect barriers. 3 types of breaches pathways to cross barriers. Corridors: easiest to cross, interconnecting habitats, river between lakes, valley between lowlands. Filter: interconnecting habitat contains limited variety of habitats, only certain organisms can survive. Sweepstakes route: the pathway to remote oceanic island via fauna/flora. Iguanas float away on waterlog tree to anguilla.
