Predation predator kills and consumes all or most of another organism prey

Predation predator kills and consumes all or most of

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- Predation: predator kills and consumes all or most of another organism (prey) - Defense from Consumption - Prey evolve defenses to counter predators - 2 basic types of defenses - Constitutive: always presented - Inducible: produced in response to predators - Camouflage: blend into the background. Ex: flat fish - Schooling: safety in numbers - Weaponry: fighting back. Ex: porcupine - Mimicry : constitutive defenses that led to 2 types of mimicry. : Mullerian mimicry: species with similar defenses resemble each other : Bastein mimicry: species with defenses resemble those with defenses - Mullerian can protect both dangerous and harmless species - [Mullerian] Sting Ex: common wasp, bee (bumble), Honeybee - [Bastein] Doesn’t sting Ex: hornet moth, wasp beetle, hoverfly - Inducible Defenses - Variable responses - Triggered by presence of predators - Defense represents a fitness cost - Inducible defense minimizes fitness cost - Ex: cottonwood tree felled by beavers (re-sprouted trees, have more defensive compound)/ Mussels and Crabs - Top down vs. bottom up control of consumption
- Predators/ prey population undergo cycles - What control these cycles? - Bottom up: amount of prey regulate predator abundance - Top down: predators control prey abundance - Ex: the hare-lynx population cycle every 11 years, on avg. the size of the lynx population lags behind that of the hare. - Population of cycles of the snowshoe hares are influenced by their food supply as well as by interactions with their predators. - Mutulaistic Interactions (+/+) - Both organism benefits - Not cooperative or altruistic - Rare case when 1.) both organism attempt to profit 2.) both are successful - Many change to consumptive/competitive relationships - Ex: clown fish and anemone / mutualism between cleaner shrimp and fishes - Ants and acacia tree: ants defend tree from grazers, tree provide ants with home and food, so both have benefits. - Indirect Directions - 2 species that do not directly interact exert influence on each other - Influence is indirect - Consequence of interaction with another species - Indirect Interaction - Trophic Cascade (Ex: otter urchin kelps) (picture in class notes) - Keystone Species: Mar. 5. 2010 - Species with effects on communities those are disproportionate to their biomass - Ex: small parts of organism but big impact - Tend to be top level predators - Species Diversity - Key feature of communities - Can be measured in two ways - Species richness = total number of species - Species diversity = weighted measure that includes both species number and abundance Community 1 Community 2 Community 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - Species richness = 6 6 5 - H (species diversity) = 0.59 0.78 0.69 - Cause/ Role of Species Diversity
- Why are some communities more diverse than others?

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