Lecture 8

Lecture 8 - - Migration as an adaptive behavior o Why do...

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- Migration as an adaptive behavior o Why do it? Historical reasons Continental drift o An example: turtles- feed in Brazil but breed on an island in middle of ocean (Ascension Island) Animals follow food resources Birds move south when food becomes scarce in winter Fish move between areas of low and high productivity in the ocean o Depends on the species o Example: salmon – krill in the ocean Animals move between protected breeding areas and feeding areas Example artic churns Example: Gray whales o Summer: feed in Artic o Winter: breed in Mexico What are some of the benefits? Increase food supplies Birds: in summer northern areas get more sunlight → more insects →less effort for foraging Fishes: freshwater offers protective spawning areas but oceans are nutrient rich Examples Anadromous fish (eg salmon) o Spawn in freshwater and migrate to the ocean Return to natal steam later to spawn Catadromous fish (eg American eels) o Spawn in Sargasso sea but migrate to freshwater in rivers in North America and Europe o Return to Sargasso to spawn Insects: o Locust Swarms
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This note was uploaded on 06/21/2011 for the course NPB 102 taught by Professor Hahn during the Spring '09 term at UC Davis.

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Lecture 8 - - Migration as an adaptive behavior o Why do...

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