Dispersal and Biogeography

A set of flashcards to review key concepts related to dispersal, biogeography, and the movements and barriers faced by species.

What is dispersal in the context of biogeography?

Dispersal is the movement of individuals away from their birthplace, including immigration and emigration.

What are the two main opposing views in the controversy of biogeography?

Dispersalists and vicariance biogeographers.

What types of movement are there for organisms?

Active movement, which is self-powered, and passive movement, which involves being carried by wind, currents, or other organisms.

What is jump dispersal?

Jump dispersal refers to crossing wide barriers to reach distant locations, as seen with organisms traveling through air or floating.

What is diffusion in terms of species spread?

Diffusion is the steady expansion of a species that is too rapid for evolution, like the cattle egret's expansion from Africa to the Americas.

What does secular migration involve?

Secular migration is the slow spread of species that undergoes evolution, such as camels spreading from North America to South America.

What is a barrier in biogeography?

A barrier is a biotic or abiotic feature that restricts the movement of individuals to new sites.

Can you give an example of a psychological barrier?

Some Pacific Island birds may not leave their islands despite the ability to fly, possibly due to selection against predators.

What did G.G. Simpson propose about dispersal routes?

He identified corridors as routes permitting the spread of taxa, filters as selective connections resulting in non-random subsets of fauna, and sweepstakes as random, unselective dispersal events.

How did Croizat contribute to panbiogeography?

He first described panbiogeography in the 1970s, emphasizing the need for formal methods of inferring past distributions from present distributions.

What is vicariance biogeography?

Vicariance biogeography suggests that most species do not disperse and that biota appear first, then get fragmented by barriers.

What was a significant criticism against panbiogeography?

It was criticized for not incorporating phylogenies.

What is the significance of the Hawaiian Archipelago in biogeography?

It serves as a case study for colonization and isolation patterns where some species show episodes of colonization followed by speciation.

What does the divergence of Madagascar species suggest about their separation?

The divergence dates of many Madagascar species indicate younger divergence than geological separation, suggesting both vicariance and multiple colonization events.