5 In Batesian mimicry A palatable or harmless species mimics an unpalatable or

5 in batesian mimicry a palatable or harmless species

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5 In Batesian mimicry – A palatable or harmless species mimics an unpalatable or harmful model (a) Hawkmoth larva (b) Green parrot snake Figure 53.7a, b In Müllerian mimicry – Two or more unpalatable species resemble each other (a) Cuckoo bee (b) Yellow jacket Figure 53.8a, b Herbivory Herbivory, the process in which an herbivore eats parts of a plant – Has led to the evolution of plant mechanical and chemical defenses and consequent adaptations by herbivores (+/-)
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6 Parasitism and Disease In parasitism, one organism, the parasite Derives its nourishment from another organism, its host, which is harmed in the process The effects of disease on populations and communities Is similar to that of parasites (+/-) My other tongue is a crustacean… Parasite grabs base of fish tongue Robs tongue of blood, tongue atrophies Parasite replaces tongue Parasite & fish share food Cymothoa exigua and the rose snapper Grasshoppers infected with fungal disease When grasshoppers close to death, climb to top of grass blades Fungal spores better dispersal Parasites can manipulate their hosts in many ways… Mutualism Mutualistic symbiosis, or mutualism – Is an interspecific interaction that benefits both species Figure 53.9 (+/+) ant Acacia in Costa Rica note thorns nesting sites for ants photos by Dan Janzen Extra-floral nectaries
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7 Beltian bodies Tree provides housing & food for ants - ants benefit Mutualism - (+/+) What does the tree get out of it? Ants patrol the tree day and night Ants attack any herbivores Vine growing near an ant acacia Same vine after it had touched the ant acacia Acacia with ants Acacia with no ants After 45 days with or without ants
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8 Acacia tree 1 year after ants had been removed Acacia tree 1 year after ants had been removed Summary: ant - acacia mutualism tree provides food, nest sites for ants ant provides tree protection from competitors, herbivores Figure 53.9 Bee pollinating milkweed flower Bee robbing nectar Mutualisms are systems of mutual exploitation and can break down into interactions that benefit one player at the expense of the other (+/+) (+/-) Commensalism In commensalism – One species benefits and the other is not affected Figure 53.10 (+/ 0 ) Species Diversity Two components – Number of species – Relative abundance of each species (evenness) Community 1 A: 25% B: 25% C: 25% D: 25% Community 2 A: 80% B: 5% C: 5% D: 10% D C B A Figure 53.11
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9 Trophic Structure Trophic structure – Is the feeding relationships between organisms in a community – Is a key factor in community dynamics Food chains Quaternary consumers Tertiary consumers Secondary consumers Primary consumers Primary producers Carnivore Carnivore Carnivore Herbivore Plant Carnivore Carnivore Carnivore Zooplankton Phytoplankton A terrestrial food chain A marine food chain Figure 53.12 – Link the trophic levels from producers to top carnivores Food Webs A food web Humans Baleen whales Crab-eater seals Birds Fishes Squids Leopard seals Elephant seals Smaller toothed whales Sperm whales Carnivorous plankton Euphausids (krill) Copepods Phyto- plankton Figure 53.13 Is a branching food chain with complex trophic interactions Trophic pyramids Food chains are usually only a few links long
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  • Spring '10
  • ChristopherWills
  • Ecology, Evolution, trophic level, Ecological niche, Chthamalus Balanus

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