Lesson 8.2 Species InteractionsThe zebra mussel has completely displaced 20 native mussel species in Lake St. Clair.

ObjectivesExplain the difference between niche and habitat.Give examples of parts of a niche.Describe the five major types of interactions between species.Explain the difference between parasitism and predation.Explain how symbiotic relationships may evolve.

The NicheLesson 5.2 Species InteractionsDescribes an organisms use of resources and functional role in a community. A niche is different from a habitat. An organisms habitat is a location. However, a niche is an organisms pattern of use of its habitat.Often restricted by competition

Ways in Which Species InteractInteractions between species are categorized at the level where one population interacts with another.

The five major types of species interactions are:CompetitionPredationParasitismMutualismCommensalism

CompetitionOrganisms compete when they seek the same limited resource.In rare cases, one species can entirely exclude another from using resources.To reduce competition, species often partition resources, which can lead to character displacement.Intraspecific Competition: among members of same speciesInterspecific Competition: among members of two or more different speciesLesson 5.2 Species Interactions

4 Types of CompetitionCompetitive ExclusionDirect competition between species resulting in a winner and loserOne species is very effective competitor by excluding another species from resources entirelyOccurs when two or more species try to occupy the same exact niche

Fundamental and Realized NicheFundamental: Full niche of speciesRealizedNiche restricted by competition

Resource PartitioningSpecies partition, or divide, the resources they use in common by specializing in different ways

Character DisplacementWhen resource partitioning can lead to the evolution of physical characteristics among the competing species that reflect their specialized role in the environment.

Predation (+/)The process by which a predator hunts, kills, and consumes preyDefensive traits such as camouflage, mimicry, and warning coloration have evolved in response to predator-prey interactions.Some predator-prey relationships are examples of coevolution, the process by which two species evolve in response to changes in each other.

Lesson 5.2 Species InteractionsDid You Know? A single rough-skinned newt contains enough poison to kill 100 people. Unfortunately for the newt, its predator, the common garter snake, has coevolved resistance to the toxin.Rough-Skinned Newt

Predators and PreyAll organisms need food and consumers must eat other organism to get it.PredatorsConsumers that actively hunt other organismsPreyOrganisms upon which the predators feed on

Predator vs PreySize of predator and prey populations are closely linkedLarge prey population=more predatorsSmall prey population=less predatorsPopulation CyclesTime it takes for a population to rise and fallSome take 10 years, some 4 yearsLifespan of organisms plays a role

ParasitismA relationship in which one organism feeds on the tissues or body fluids of another.Examples: Ticks, Fleas, lice, variety of wormsHostOrganism in which the parasite feedsTrue parasiteAdapted to live on or in the host

Parasitism Cont.Population size is related to size of host

Thrive in crowded host populations

Density-dependent limiting factor because parasite is more successful in a dense host population

SymbiosisRelationship where two species live together closelyParasitism is a form of symbiosisOne organism is harmed while one benefitsCommensalismRelationship that benefits one species and neither helps or harms the otherBarnacles on a whale

Symbiosis Cont.MutualismRelationship where both species benefitAnts and Acacia TreeFlowers and InsectsA remarkable 3-way mutualism appears to have evolved between an ant, a butterfly caterpillar, and an acacia in the American southwest. The caterpillars have nectar organs which the ants drink from, and the acacia tolerates the feeding caterpillars. The ants appear to provide some protection for both plant and caterpillar.

VideosPredator Vs Prey Videohttp://www.youtube.com/watch?v=pVX49KhH0mcParasitismhttp://www.youtube.com/watch?v=EWB_COSUXMwSymbiotic Relationshipshttp://www.youtube.com/watch?v=pMN1zI2Dm4c

8.2 Quiz1. Explain how competition can affect an organisms niche.3. The human digestive tract is filled with bacteria. The bacteria live in the body and get nutrients while helping to digest food. What kind of species interaction is this-mutualism or commensalism? Is it symbiotic? Explain4. Copy the chart below and place a (+) or (-) to indicate the species interaction.

InteractionEffect on Species AEffect on Species BCommensalismCompetitionHerbivoryMutualismParasitismPredation

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