Species InteractionsSpecies Interactions

Clarifying Objective 2.1.3 Clarifying Objective 2.1.3 Explain various ways organisms interact with each other Explain various ways organisms interact with each other

including predation, competition, parasitism, and including predation, competition, parasitism, and mutualism.mutualism.

Within all ecosystems, species interact in various ways. Within all ecosystems, species interact in various ways.

Photosynthetic organisms Photosynthetic organisms convert carbon dioxide and convert carbon dioxide and water into food and oxygen water into food and oxygen for the rest of the organisms for the rest of the organisms

in the ecosystem.in the ecosystem.

Interactions within EcosystemsInteractions within Ecosystems

Animals produce organic Animals produce organic waste that plants use as waste that plants use as

fertilizer so they can fertilizer so they can grow healthy and strong.grow healthy and strong.

Decomposers recycle Decomposers recycle minerals and other minerals and other nutrients within the nutrients within the

ecosystem.ecosystem.

Interactions within EcosystemsInteractions within Ecosystems

Certain bacteria “fix” Certain bacteria “fix” atmospheric nitrogen atmospheric nitrogen into an organic form into an organic form

that plants can use and that plants can use and pass on to animals.pass on to animals.

SymbiosisSymbiosisHowever, sometimes two different species will form a However, sometimes two different species will form a closeclose and and permanentpermanent relationship that then becomes relationship that then becomes

part of each of the species niches.part of each of the species niches.

These close, permanent relationships between two These close, permanent relationships between two different species is called different species is called symbiosissymbiosis..

Lichen

SymbiosisSymbiosisLichenLichen is a symbiotic relationship between different is a symbiotic relationship between different

species of species of algaealgae and different species of and different species of fungifungi. .

Fungus

Algae

Through photosynthesis, the Through photosynthesis, the algaealgae providesprovides foodfood to to the fungi. In turn, the the fungi. In turn, the fungifungi protectsprotects the the algaealgae cells cells from dying out because they are able to store large from dying out because they are able to store large

amounts of water for long periods of time.amounts of water for long periods of time.

SymbiosisSymbiosisBecause of this symbiotic relationship, lichen can Because of this symbiotic relationship, lichen can be found in a be found in a widewide rangerange of of habitatshabitats, including the , including the

arctic tundra.arctic tundra.

Reindeer feed Reindeer feed mainly on lichen mainly on lichen during the winter.during the winter.

Lichen on Wood Lichen on Rocks

SymbioticSymbioticIn a similar fashion, In a similar fashion, coralcoral is also often thought of as is also often thought of as one organism but actually consists of a symbiotic one organism but actually consists of a symbiotic

relationship between an relationship between an algaealgae and an and an animalanimal..

The The algaealgae benefit because they have a substrate benefit because they have a substrate upon which they can upon which they can reachreach the the sunlightsunlight to to

photosynthesize and the photosynthesize and the coralcoral benefit from the benefit from the oxygenoxygen and and sugarsugar the algae provide. the algae provide.

Symbiodium Symbiodium AlgaeAlgae

CoralCoral

Not a plant Not a plant because it cannot because it cannot make its own food make its own food and does not have and does not have plants structures plants structures but instead has but instead has

tentacles that they tentacles that they capture food with.capture food with.

SymbiosisSymbiosisThere are There are threethree different different typestypes of symbiotic of symbiotic

relationships:relationships:

MutualismMutualism ParasitismParasitism

CommensalismCommensalism

Dung Beetle

MutualismMutualismIn a mutualistic relationship, In a mutualistic relationship, bothboth speciesspecies benefitbenefit. .

While While pollinatingpollinating animalsanimals collect nectar, pollen collect nectar, pollen

becomes attached to their becomes attached to their bodies. When they move bodies. When they move to other to other flowersflowers, the pollen , the pollen

is transferred and is transferred and pollination occurs.pollination occurs.

Pollinator benefits from a high energy Pollinator benefits from a high energy mealmeal and and the plant benefits because it is able to the plant benefits because it is able to reproducereproduce..

MutualismMutualismBees are not the only pollinators. There are Bees are not the only pollinators. There are severalseveral

different types of different types of animalsanimals that also help that also help pollinatepollinate flowering plants. flowering plants.

ButterfliesButterflies

BatsBats

Honey PossumsHoney Possums

HummingbirdsHummingbirds BeetlesBeetles

LizardsLizards

ParasitismParasitismIn a parasitic relationship, In a parasitic relationship, oneone species is species is harmedharmed, while , while

the the otherother species species benefitsbenefits. .

The species that is The species that is harmed is called harmed is called the the hosthost and the and the

species that species that benefits is called benefits is called

the the parasiteparasite..

Parasitic relationships differ from predator-prey Parasitic relationships differ from predator-prey relationships in that the parasite usually relationships in that the parasite usually doesn’tdoesn’t initially initially killkill the host, if it even kills the host at all. the host, if it even kills the host at all.

ParasiteParasite

HostHost

Fleas

ParasitismParasitismSome parasites are carried from one host to another Some parasites are carried from one host to another

host through another animal, called a host through another animal, called a vectorvector..

MosquitoesMosquitoes are a common vector. are a common vector.

ParasiteParasite VectorVector HostHost

ElephantitisElephantitis

ParasitismParasitismMalariaMalaria is caused by a parasitic microscopic organism is caused by a parasitic microscopic organism

called a protozoan that uses the called a protozoan that uses the mosquitoesmosquitoes and and humanshumans to help complete its to help complete its reproductivereproductive cyclecycle..

1.1. Mosquito injects parasite Mosquito injects parasite when it bites the human.when it bites the human.

2.2. Protozoan parasite travels to Protozoan parasite travels to liver cells and then red blood liver cells and then red blood cells.cells.

3.3. Another mosquito bites an Another mosquito bites an infected human and ingests infected human and ingests the protozoan parasite.the protozoan parasite.

4.4. Protozoan parasite sexually Protozoan parasite sexually reproduces in the gut of the reproduces in the gut of the mosquito.mosquito.

CommensalismCommensalism

SpanishSpanish mossmoss grows on trees grows on trees to reach sunlight. Because to reach sunlight. Because they can photosynthesize its they can photosynthesize its

own food, as well as obtain its own food, as well as obtain its own moisture and nutrients own moisture and nutrients

from the air, it does not harm from the air, it does not harm the trees at all. the trees at all.

While the While the treetree is not harmed by the Spanish moss, it is not harmed by the Spanish moss, it also receives no benefit.also receives no benefit.

In a commensalistic relationship, In a commensalistic relationship, oneone species species benefitsbenefits while the while the otherother species is species is notnot affectedaffected at all. at all.

Competition and Predator-Prey Competition and Predator-Prey RelationshipsRelationships

Two other types of interactions found in ecosystem are Two other types of interactions found in ecosystem are competitioncompetition and and predator-preypredator-prey relationships. relationships.

Although these relationships involve interactions Although these relationships involve interactions between different species, they are between different species, they are notnot as as speciesspecies

specificspecific as the symbiotic relationships. as the symbiotic relationships.

CompetitionCompetition Predator-PreyPredator-Prey

CompetitionCompetitionCompetition between two different species can occur Competition between two different species can occur over over anyany resourceresource such as such as foodfood, , waterwater, and , and spacespace..

In the west, they have an open range policy where In the west, they have an open range policy where any and all ranchers can allow their herds of cows to any and all ranchers can allow their herds of cows to

graze freely anywhere on the range. Competition graze freely anywhere on the range. Competition between between cowscows and wild and wild deerdeer arise as more cows are arise as more cows are

allowed to graze on the range.allowed to graze on the range.

CompetitionCompetitionCompetition often occurs between Competition often occurs between plantsplants. .

When When non-nativenon-native plants are introduced plants are introduced to an area, they often to an area, they often

out-compete the out-compete the nativenative plants for water, plants for water,

minerals, and space.minerals, and space.

In the competition relationship, the one who can In the competition relationship, the one who can out-competeout-compete the other is the species that the other is the species that

benefitsbenefits..

KudzuKudzu

Predator-PreyPredator-PreyPredator-prey relationships occur when one Predator-prey relationships occur when one

species, the species, the predatorpredator, , killskills and and eatseats the other the other species, the species, the preyprey..

GrazersGrazers are common prey for carnivorous are common prey for carnivorous predators. predators.

Predator-PreyPredator-PreyThe predator-prey relationship is crucial in keeping The predator-prey relationship is crucial in keeping

the the ecosystemecosystem in in balancebalance..

Too many grazers results in Too many grazers results in overgrazing and starvation.overgrazing and starvation.

Natural predators, keep the Natural predators, keep the number of grazers down. number of grazers down.

However, too many predators However, too many predators results in overhunting and eventual results in overhunting and eventual

starvation of predators.starvation of predators.

As the number of predators decrease, the grazer populations begin to As the number of predators decrease, the grazer populations begin to increase again and the cycle repeats itself.increase again and the cycle repeats itself.

The EndThe End

Nemo’s science question

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