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Thorson's Rule
R vs K strategists decline a long a gradient of decreasing latitude or water temperature applied to only marine invertebrates.
Hypothesized mechanisms
: 2 principal modes of development for mollusks and gastropods.
1) the larva may become planktonic and disperse with the water currents away from the natal range.
2) Many undergo direct development to adults in the natal home range.
Gloger's Rule
More pigmented forms in humid areas. Animals are darker close to the equator.
Animals have less intense pigmentation in less humid areas (higher latitude)
There is more bacteria in humid areas and darker coloration provides better resistance to microbial organisms.
Better UV protection.
Examples
: Birds
Allen's rule
forms living in warmer environments (low elevation/low latitude) have longer appendages.
Shorter appendages promote heat conservation in cold environments by reducing total surface area for heat loss
Long appendages= heat dissipation (ears/legs)
Rapoport's rule
Tendency for geographic range size to increase with latitude
Bergmann's rule
Body size of endotherms is positively correlated to latitude
fewer small endotherms at higher latitudes
improved cold tolerance
less evaporative cooling in large endotherms
Ex
: Bears
Vermeij's hypothesis
Greater predator and prey offenses/defenses toward lower latitudes
Greater diversity in tropics due to predation pressure causing prey speciation, which in turn contributes to predator speciation.
Why biodiversity is higher in some regions than others.
Reduced seasonality
Greater number of niches
Predation/Competition
Time for speciation to occur
etc.
Author
kamrunsreno
ID
253618
Card Set
Ecological Rules
Description
Final Exam
Updated
2013-12-17T20:08:16Z
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