Week15 - 4/29/2010 Adaptions of predators Encounter detect...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
4/29/2010 1 Adaptions of predators Encounter – detect – attack – capture – ingest Sit and wait: pike, odonates , hydra , carnivorous plants Sensing prey – visual, mechanical, tactile, chemical cues, electrically Optimal foraging ecology www.utexas.edu/. ../HaroldZakon/research.html Optimal foraging ecology Evolution through selection leads to maximization of net energy gained per unit time feeding . Density –spatial distribution Ease of capture Foraging can be Modified by Food Density 0.0 0.2 0.4 0.6 0.8 1.0 Proportion in gut (relative to largest size class) 1.4 2.5 3.6 25 prey per bluegill 0.0 0.2 0.4 0.6 0.8 1.0 1.4 2.5 3.6 300 prey per bluegill Daphnia size (mm) 0 1 2 3 4 5 Selectivity (proportion relative to expected encounter rates) 1.4 2.5 3.6 Daphnia size (mm) 0 1 2 3 4 5 1.4 2.5 3.6 Nonlethal effects of predation Injury Restrict habitat use Restrict foraging behavior Changes in life history http://farm1.static.flickr.com/73/229909665_a2fcf36cb0.jpg?v=0 www.allposters.com
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Non-lethal Effects of Predation Many predators don’t kill prey, but can alter their survival Another prey species may be your savior if a predator switches to that prey instead of you when your population numbers are low Macrophytes are not eaten entirely, but can be grazed to some degree ht p:/ floridakeystreasures.com/keysblog/wp-content/uploads/2010/02/manatee2.jpg Trophic cascade 1880: Camerano postulated that animals can control the biomass of lower trophic levels and diagrammed how a carnivore can control herbivore populations and positively influence plants ( primary producers ). Ripple, W. J., E. J. Larsen, R. A. Renkin, and D. W. Smith. 2001. Trophic cascades among wolves, elk and aspen on Yellowstone National Park's northern range. Biological Conservation 102:227-234. doi:10.1016/S0006-3207(01)00107-0
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 8

Week15 - 4/29/2010 Adaptions of predators Encounter detect...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online