Question 1

What is biogeography and how does it explain species distribution?

Accepted Answer

Biogeography is the study of organism distribution across geographic space and the processes shaping these patterns. The theory states that species in any location either evolved there or immigrated from elsewhere. Environmental characteristics like food availability and interactions with other species determine whether colonizers establish new populations or perish in their new habitat.

Question 2

How do island size and mainland proximity affect species colonization rates?

Accepted Answer

Islands closer to the mainland experience greater colonization rates because organisms can more easily disperse shorter distances. Larger islands support more species than smaller ones due to greater resources, niches, and larger population sizes that reduce extinction risk. These factors combine to determine the total number of species an island can sustain.

Question 3

What is dynamic equilibrium in island biogeography?

Accepted Answer

Dynamic equilibrium occurs when colonization and extinction rates balance, stabilizing the total number of species on an island. Although species composition changes as new immigrants arrive and residents go extinct, the overall species count remains relatively constant. This equilibrium point is unique to each island based on its size, resources, and proximity to the mainland.

Question 4

Why does extinction rate increase as more species inhabit an island?

Accepted Answer

As species diversity increases, extinction risk rises due to increased antagonistic interactions like predation and competition. More species also means fewer available resources and niche space for new arrivals. Statistically, more species simply create more opportunities for extinction events to occur among the coexisting populations.

Question 5

How has island biogeography theory been applied beyond oceanic islands?

Accepted Answer

Island biogeography principles apply to isolated habitats like sky islands, inland lakes, and forests fragmented by agriculture. These non-continuous habitats function similarly to oceanic islands, with species experiencing isolation and limited dispersal. Understanding these dynamics helps conservation biologists design habitat corridors and reserves to maintain species diversity and prevent extinction.

Question 6

What factors determine whether colonizing species establish populations in new locations?

Accepted Answer

When colonizers arrive at a new location, environmental characteristics including food availability and interactions with existing species determine establishment success. Species must overcome biological limitations to disperse, such as limited flight range for birds or seed drift constraints. Birth and immigration rates must equal or exceed death and emigration rates for populations to persist.

Question 7

Why are endemic species in isolated habitats at greater extinction risk?

Accepted Answer

Endemic species found only in isolated locations face higher extinction risk due to smaller population sizes and limited habitat areas. These species evolved under specific local environmental pressures and lack genetic diversity from outside populations. Understanding biogeography principles helps conservation efforts protect these vulnerable species through habitat management and artificial corridors connecting fragmented areas.

Species Distribution and Biogeography

Species Distribution

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