23 Major Types of Community Interactions Recall: What is a community?Community = assemblage of populations interacting with one another within the same environmentOrganisms within a community interact with each other in 3 major ways:- Competition- Predation- SymbiosisLet’s look at each of these interactions in more detail.
3What is Competition? Competition Competitive Exclusion Principle Occurs when members of different species try to utilize a resource (such as light, space, or nutrients) that is in limited supply.Results in a winner and a loser.Think of sports teams when they compete.Scenario #2 in our opening demonstrationCompetitive Exclusion PrincipleNo two species can occupy the same ecological niche in the same habitat at the same time.
4What is Predation? Predation Occurs when one living organism feeds on another living organism.Involves predator and preyPredator = organism that feedson another organismPrey = organism that is the foodExample: Lynx and bunnyIn today’s lab, we’ll examine a predator-prey relationship.Figure Source:images/LynxAttackRabbit2.jpg
5Mimicry- An Antipredator Defense 2 main types– Batesian & MullerianBatesian MimicryA harmless species resembles a poisonous or distasteful speciesThe harmless mimic is protected b/c it is often mistaken to be its dangerous look-alikeExample: A king snake (nonpoisonous) resembles a coral snake (poisonous)King Snake Coral Snake
6Mimicry- An Antipredator Defense Mullerian MimicryWhen 2 or more dangerous or distasteful species look similar.Each species involved benefits b/c a predator that encounters an individual of 1 species will avoid similar individuals.Example: Bees & wasps have similar patterns of alternating yellow & black stripes.
7What is Symbiosis? Symbiosis Let’s look at each type… Refers to the close interactions between members of two species.3 major types► Parasitism► Commensalism► MutualismLet’s look at each type…Figure Source:birding/CattleEgret(JM).jpg
8ParasitismWhat is it?A relationship in which one organism lives on or in another organism and gets its nourishment from it.One organism is harmed (host) and one organism benefits (parasite)Example:Deer ticks on dogsCan you think of any others?
9Commensalism What is it? Relationship in which one organism benefits and other organism is not hurt or helped.One organism often provides a home and/or transport for the other organism.Example:Barnacles that attach themselves to backs of whalesThe whale is not affected.The barnacles benefit from transportation and eat small food particles in the water.Can you think of any others?
10Mutualism What is it? A relationship in which both members benefit. Think of a “mutual agreement” both parties benefit!Example:Bees and flowers.Bee benefits because eatsnectar (food).Flower benefits because the beespreads its pollen (reproduction).Can you think of any others?
11SymbiosisYou can think of the various types of symbiosis as almost a continuum…Parasitism Commensalism Mutualism( + / - ) ( + / 0 ) ( + / + )An extremeHelps one memberHurts other memberIn the middleHelps one memberNo affect on other memberAn extremeHelps both members
12Checking your understanding– Quick Questions What is a community?What is the Competitive Exclusion Principle?What is predation?What is the name of the symbiotic relationship in which both organisms benefit?What is the name of the symbiotic relationship in which one organism benefits and other is not helped or harmed?What is the name of the symbiotic relationship in which one organism benefits but other is harmed?
13Find an exampleUsing a computer or a smart phone, please find one example of a predator/prey relationship, a symbiotic relationship (be able to determine the type: mutualism, commensalism or parasitism)Please find examples that we haven’t discussed in class.
14Homework for tonight: Read pages 128-147 about biomes. We will be playing biome bingo and doing an activity about biomes over the next two days.Unit 2 Test will be on Friday! 10/5In class review on Thurs. 10/4