Chapter 4 Dispersal And Immigration Flashcards
Spatial distribution of a population.
Dispersion
Movement of organisms away from their point of origin.
Dispersal
Seasonal movements between two or more locations.
Migration
Fundamental pressures in biogeography.
Evolution - adapt
Extinction - die
Dispersal - move
Gradual expansion. Establishment at or near boundaries.
Diffusion
Long distance dispersal. Organisms are successfully crossing barriers.
Jump Dispersal
Very slow range expansion in which new species evolve in route.
Secular Migration
Active movement. Usually relatively large animals. Dispersal through flight, swimming, or walking.
Vagility
Passive dispersal. Includes seed dispersal of plants through windblown, adherent, dehiscent, or fleshy fruits. Spores, cysts, planktonic stages, rafts, phoresy.
Pagility
A commensal relationship where the primary benefit is transportation of one organism by the other. (not including parasites)
Phoresy
Any biotic or abiotic feature that totally or partially restricts movement from one location to another.
Barriers
Abiotic factors restricting movement. Ex: salt vs freshwater, land vs water, cold vs warm temp.
Physiological barriers
Species strongly prefers a certain habitat. May be able to physically cross barrier but choose not to.
Psychological Barriers
Predation and competition restricting dispersal.
Biotic Barriers
Dispersal route that allows many taxa to cross. Ex: land bridge or valley (Beringia) any continuous biomass.
Corridor
Dispersal route that some species can cross, but moderately to severely difficult for other species to cross.
Number of species declines as you go through. Ex: island chains
Filter
Dispersal route that is unlikely to be crossed by any species because it involves crossing a significant barrier.
Sweepstakes Route
Unit necessary to start a new colony.
Propagule
Produces viable seeds from unfertilized ovules. (Dandelions)
Apomictic
All are females and produce female offspring asexually. (Some fish, amphibians, reptiles, and geckos on some islands.)
Parthenogenetic
Worldwide or nearly. Taxa that are very widespread. (Some whales, Peregrine falcon, duckweed, daphnia)
Cosmopolitan
A taxon occurs only in one geographic area and nowhere else. Commonly occurring on islands. (Galapagos Tortoises)
Endemic
An endemic group evolved within an area.
Autochthonous
Endemic group evolved and then moved into an area.
Allochthonous
A taxon that was once widespread and now only occurs in a small area.
Biogeographic Relict
A taxon that was a part of a much more diverse group, but now is a sole survivor. (Ginkgo biloba)
Taxonomic Relict
Taxon that is endemic for a very long time.
Paleoendemic
Taxon that has recently become endemic. (Bristlecone Pine)
Neoendemic
When several different groups are endemic to the same area.
Provincialism
Zoogeographic region of North America
Nearctic
Zoogeographic region of Europe, Asia, and North Africa
Palearctic
Zoogeographic region of Nearctic and Palearctic together.
Holarctic
Zoogeographic region of Central America and South America.
Neotropical
Zoogeographic region of Africa below the Sahara Desert and Madagascar.
Ethiopian
Zoogeographic region of Southeast Asia and adjoining continental islands.
Oriental
Zoogeographic region of Australian continent and Oceania regions.
Australia
Phytogeographic region of Nearctic and Palearctic (Laurasia)
Holarctic Realm
Phytogeographic region of Eastern Gondwanaland
Holotropical Realm
Phytogeographic region of Western Gondwanaland
Austral Realm
Island that never has a continental connection, formed at hotspots, trenches, or ridges.
Oceanic
Island that was connected with continents and either broke off or connected in low water times.
Continental Island
A taxon occurs in two or more widely separated areas.
Disjunction
