Types of InteractionsTypes of Interactions

Section 3Section 3

ObjectivesObjectives

Distinguish between the two types of Distinguish between the two types of competitioncompetition

Give examples of predators and preyGive examples of predators and prey Distinguish between mutualism, Distinguish between mutualism,

commensalism and parasitismcommensalism and parasitism Define coevolution and give an exampleDefine coevolution and give an example

Interactions with the EnvironmentInteractions with the Environment

Limiting FactorsLimiting Factors: Populations cannot grow : Populations cannot grow indefinitely because the environment indefinitely because the environment contains only so much food. contains only so much food. – Example: Food Example: Food

Carrying CapacityCarrying Capacity: The largest population : The largest population that a given environment can support over a that a given environment can support over a long period of timelong period of time– Example: FoodExample: Food

Interactions Among OrganismsInteractions Among Organisms

CompetitionCompetition Predators and PreyPredators and Prey SymbiosisSymbiosis CoevolutionCoevolution

CompetitionCompetition

When two or more individuals or populations When two or more individuals or populations try to use the same limited resources (food, try to use the same limited resources (food, water, shelter, space, or sunlight).water, shelter, space, or sunlight).

Can occur among individual organisms or a Can occur among individual organisms or a populationpopulation

Often during winter when resources are Often during winter when resources are scarce scarce

Predator and PreyPredator and Prey

Predator: the organism that eats the preyPredator: the organism that eats the prey Predator adaptations: must be able to catch Predator adaptations: must be able to catch

their preytheir prey– Run fastRun fast– Quick reflexes Quick reflexes – StalkStalk

Predator and PreyPredator and Prey

Prey: the organism that Prey: the organism that is eaten is eaten

Prey Adaptations: Prey Adaptations: methods and abilities to methods and abilities to keep from getting eatenkeep from getting eaten– PoisonousPoisonous– Run (fast)Run (fast)– Heightened senses Heightened senses

(hear, see, smell)(hear, see, smell)– CamouflageCamouflage

SymbiosisSymbiosis

Symbiosis: a close, long-term association Symbiosis: a close, long-term association between two or more speciesbetween two or more species– MutualismMutualism– CommensalismCommensalism– ParasitismParasitism

MutualismMutualism

A symbiotic relationship in which both A symbiotic relationship in which both organisms benefitorganisms benefit

Coral and Algae – Coral provides a home Coral and Algae – Coral provides a home and Algae provides foodand Algae provides food

CommensalismCommensalism

A symbiotic A symbiotic relationship in which relationship in which one organism benefits one organism benefits and the other is and the other is unaffectedunaffected

Sharks and remoras; Sharks and remoras; remoras “hitch a ride” remoras “hitch a ride” and feed on scraps and feed on scraps while the shark is while the shark is unaffectedunaffected

ParasitismParasitism

A symbiotic association in which one A symbiotic association in which one organism benefits and the other is harmedorganism benefits and the other is harmed

Parasite- organism that benefitsParasite- organism that benefits Host- organism that is harmedHost- organism that is harmed Tomato Hornworm – see page 18Tomato Hornworm – see page 18

CoevolutionCoevolution

A long-term change that takes place in two A long-term change that takes place in two species because of their close interactions species because of their close interactions with one another. with one another.

See page 18 for example and picturesSee page 18 for example and pictures

Inquiry LogsInquiry Logs

How do organisms survive in different How do organisms survive in different environments?environments?

Today you learned….Today you learned…. This answers part of our unit questions by…This answers part of our unit questions by… I know have questions about… I know have questions about…