21-3 Interactions 21-3 Interactions Among Living ThingsAmong Living Things

o Every organism has a Every organism has a variety of adaptations variety of adaptations that are suited to its that are suited to its specific living specific living conditionsconditions

NichesNichesNiche:Niche: an organisms an organisms particular role or how it particular role or how it makes its living makes its living includingincluding its types of food, how it its types of food, how it gets it, what species use it gets it, what species use it for food, when and how it for food, when and how it reproduces, and the physical reproduces, and the physical conditions it needs for conditions it needs for survivalsurvival

The 3 Major Types of The 3 Major Types of Interactions BetweenInteractions BetweenOrganisms Organisms (competition, (competition,

predation,symbiosis)predation,symbiosis)

1.) Competition:Competition: the struggle the struggle between organisms to survive in between organisms to survive in a habitat with limited a habitat with limited resources. resources.

For example, on the savannah, For example, on the savannah, many organisms are herbivores many organisms are herbivores and compete with each other for and compete with each other for available forage (grasses, available forage (grasses, leaves, etc)leaves, etc)

3 Major Interactions 3 Major Interactions (cont.)(cont.)

* Many organisms develop adaptations to * Many organisms develop adaptations to avoidavoid competition. For example, some competition. For example, some plants produce toxins that retard the plants produce toxins that retard the growth of other plants, reducing growth of other plants, reducing competition with other plants for competition with other plants for available resourcesavailable resources

2.) Predation2.) Predation:: an an interaction where one organism hunts and interaction where one organism hunts and kills another for food.kills another for food.There are There are twotwo types of types of predation predation adaptationsadaptations: : Predator adaptationsPredator adaptations and and Prey adaptationsPrey adaptations..Predator adaptations:Predator adaptations: adaptations that adaptations that help them catch food like a cheetah’s help them catch food like a cheetah’s speed (or claws) or the venom of a cobra.speed (or claws) or the venom of a cobra.

DinnerDinner!!!!!!

Run Away…Run Away…Run…Run Away…Run Away…Run…aghh !!!aghh !!!

Prey AdaptationsPrey Adaptations

Prey Adaptations:Prey Adaptations: these are defensive these are defensive adaptations that help adaptations that help an organism an organism avoidavoid predation. predation.

These include:These include:

Camouflage :Camouflage : adaptations adaptations which help an organism which help an organism

blend into their blend into their backgroundsbackgrounds

Camouflage :(cont.)Camouflage :(cont.)

Warning Coloring:Warning Coloring: bright bright colors warn predators that colors warn predators that

these organism are poisonous or these organism are poisonous or noxiousnoxious

Mimicry:Mimicry: this strategy this strategy relies on making the relies on making the organism appear to be organism appear to be

another more dangerous oneanother more dangerous one

Mimicry (cont.)Mimicry (cont.)

False Coloring:False Coloring: this this adaptation confuses or adaptation confuses or

startles predatorsstartles predators

Protective Coverings:Protective Coverings: these make it difficult or painful these make it difficult or painful to prey on these animals so to prey on these animals so predators tend to avoid them.predators tend to avoid them.

3 Major Interactions 3 Major Interactions (cont.)(cont.)

3.) 3.) Symbiosis:Symbiosis: a close a close relationship between two relationship between two species that benefits at species that benefits at least one species.least one species.

There are at There are at threethree types of types of symbiotic relationships: symbiotic relationships: mutualismmutualism, , commensalismcommensalism, , andand parasitism.parasitism.

MutualismMutualismMutualism:Mutualism: a relationship where a relationship where both species benefit both species benefit ((bees and bees and flowering plantsflowering plants))..

CommensalismCommensalism

Commensalism:Commensalism: a relationship a relationship where one species benefits and where one species benefits and the other is neither helped the other is neither helped nornor harmed (birds nesting in trees)harmed (birds nesting in trees)

ParasitismParasitismParasitism:Parasitism: a relationship a relationship where one organismwhere one organism-called the -called the parasite-parasite- benefits by living benefits by living on or inside anotheron or inside another-called -called the host-the host- , harming it. , harming it. ((ticks, leeches, tapewormsticks, leeches, tapeworms).).

Parasites (continued)Parasites (continued)