2. 6.1 Relationships in the Ecosystem Objectives: 1. Explain the relationship between the population sizes of predator prey. 2. Define symbiosis and describe several symbiotic relationships.
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15. Predators can allow coexistence of competing prey Starfish competitors predator Pisaster Barnacles Mussels Balanus Mytilus
17. time starfish removed % of inter- tidal zone mussels barnacles - mussels are the dominant competitor - competitive exclusion of barnacles - starfish allow coexistence of competitors
18. Starfish are picky – they prefer the dominant competitor, which allows the weaker competitor to coexist. How do starfish promote coexistence? Starfish Pisaster Barnacles Mussels
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34. Predator and Prey Population Cycling. World predator and prey populations can cycle in size.
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37. How has predation influenced evolution? Adaptations to avoid being eaten: spines (cacti, porcupines) hard shells (clams, turtles) toxins (milkweeds, some newts) bad taste (monarch butterflies) camouflage warning colors mimicry
41. Mimicry – look like something that is dangerous or tastes bad
42. Mimicry – looks like something that is dangerous or tastes bad Mullerian mimicry convergence of several unpalatable species
43. Mimicry – look like something that is dangerous or tastes bad Batesian mimicry – palatable species mimics an unpalatable species model mimic model mimics
