Foraging for Wild Food by Jack Abrahamson. Foraging for Wild Food Foraging for Edible Wild Foods By.
Tidal rhythms (periods ~ 12.4 hours) fiddler crab foraging.
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Transcript of Tidal rhythms (periods ~ 12.4 hours) fiddler crab foraging.
![Page 1: Tidal rhythms (periods ~ 12.4 hours) fiddler crab foraging.](https://reader030.fdocuments.in/reader030/viewer/2022033101/56649f385503460f94c54aae/html5/thumbnails/1.jpg)
• Tidal rhythms (periods ~ 12.4 hours)• fiddler crab foraging
![Page 2: Tidal rhythms (periods ~ 12.4 hours) fiddler crab foraging.](https://reader030.fdocuments.in/reader030/viewer/2022033101/56649f385503460f94c54aae/html5/thumbnails/2.jpg)
![Page 3: Tidal rhythms (periods ~ 12.4 hours) fiddler crab foraging.](https://reader030.fdocuments.in/reader030/viewer/2022033101/56649f385503460f94c54aae/html5/thumbnails/3.jpg)
Free running vs Entrained
• In constant conditions (DD), the period is slightly less than 24 hours, so each day it starts earlier
• In a predictable light cycle (LD), wheel running becomes entrained to a 24 hour period
• Light is the zeitgeber = “time giver”
![Page 4: Tidal rhythms (periods ~ 12.4 hours) fiddler crab foraging.](https://reader030.fdocuments.in/reader030/viewer/2022033101/56649f385503460f94c54aae/html5/thumbnails/4.jpg)
Actogram showing free-running & entrained rhythms in cricket singing
LL schedule
LD schedule
The animal’s behavior free-runswithout a zeitgeber
With a zeitgeberthe animal’s internalclock is reset each day by exogenouscues (the light-darkcycle)
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SCN Lesions in hamsters
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Environmental cues reset the internal circadian clock daily
Synchronization of internalclock with external cues via entrainment pathways
The pacemaker sends out signals to coordinate physiology & behavior
![Page 7: Tidal rhythms (periods ~ 12.4 hours) fiddler crab foraging.](https://reader030.fdocuments.in/reader030/viewer/2022033101/56649f385503460f94c54aae/html5/thumbnails/7.jpg)
Endogenous rhythms
The rhythms persist even when animals are kept under constant conditions
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Infradian rhythms within the annual hibernation period: