Ecology: Species Ecology: Species InteractionsInteractionsCh. 8-2Ch. 8-2

Community EcologyCommunity Ecology Just as populations contain interacting Just as populations contain interacting

members of a single species, communities members of a single species, communities contain interacting populations of many contain interacting populations of many species.species. There are 5 major interactions between There are 5 major interactions between

species:species: PredationPredation CompetitionCompetition ParasitismParasitism MutualismMutualism CommensalismCommensalism

PredationPredation

An individual of one species, called a An individual of one species, called a predatorpredator, , eats all or part of an individual of another eats all or part of an individual of another species, called the species, called the prey.prey.

Predation is powerful in a communityPredation is powerful in a community Influences the size of each population and how each Influences the size of each population and how each

species livesspecies lives Examples of Predators:Examples of Predators:

CarnivoresCarnivores HerbivoresHerbivores (all heterotrophs are either predators, parasites, or (all heterotrophs are either predators, parasites, or

both)both)

Predator AdaptationsPredator Adaptations

What makes a good predator? What makes a good predator? Natural selection favors the evolution of predator Natural selection favors the evolution of predator

adaptations for finding, capturing, and consuming adaptations for finding, capturing, and consuming preyprey

Ex:Ex: RattlesnakesRattlesnakes WolvesWolves SpidersSpiders CheetahCheetah TigersTigers

Adaptations in Animal Adaptations in Animal PreyPrey

What are some adaptations that organism’s What are some adaptations that organism’s use to avoid predation?use to avoid predation? Natural Selection favors traits that allow prey to Natural Selection favors traits that allow prey to

escape, avoid, or ward off predatorsescape, avoid, or ward off predators Some fleeSome flee Others escape by hiding or resembling other Others escape by hiding or resembling other

objectsobjects Deceptive markings (false eyes or heads)Deceptive markings (false eyes or heads) Chemical Defenses and bright colorsChemical Defenses and bright colors

Prey AdaptationsPrey Adaptations

MimicryMimicry Mimicry: this is a defense where a Mimicry: this is a defense where a

HARMLESS species mimics a dangerous HARMLESS species mimics a dangerous or distaste full speciesor distaste full species

It does this so that its predators will think it is poisonous It does this so that its predators will think it is poisonous or distasteful. It is protected because it looks like or distasteful. It is protected because it looks like someone else who is dangerous!someone else who is dangerous!

Can you guess which Can you guess which snake is the MIMIC? snake is the MIMIC?

"Red on yellow, kill a fellow. Red on black, won't "Red on yellow, kill a fellow. Red on black, won't hurt Jack." hurt Jack."

Scarlet king snake on the left is the mimic, and Scarlet king snake on the left is the mimic, and the coral snake on the right is the venomous onethe coral snake on the right is the venomous one

Adaptations in Plant PreyAdaptations in Plant Prey

Plants cannot run from predators so they Plants cannot run from predators so they have developed their own defenses.have developed their own defenses. Sharp thorns, spikes, sticky hairs, or tough Sharp thorns, spikes, sticky hairs, or tough

leavesleaves Chemical defenses (secondary compounds)Chemical defenses (secondary compounds)

Plant DefensesPlant Defenses

COMPETITIONCOMPETITION

A Niche is an organism’s role in its A Niche is an organism’s role in its environment (where it lives, what it eats, what environment (where it lives, what it eats, what resources it uses etc).resources it uses etc).

Competition happens when two organisms Competition happens when two organisms have overlapping niches or when resources have overlapping niches or when resources are limited. are limited.

The competitive exclusion principle says “no The competitive exclusion principle says “no two organisms can survive with the same exact two organisms can survive with the same exact niche”… one has to be eliminated by the niche”… one has to be eliminated by the competition. competition.

CompetitionCompetition

If 2 species share the same niche, If 2 species share the same niche, something has to happen:something has to happen: One will get killedOne will get killed Share (Resource Partitioning)Share (Resource Partitioning) One species will be pushed out One species will be pushed out

or leaveor leave Evolve to be different (Character Evolve to be different (Character

Displacement)Displacement)

What are symbiotic What are symbiotic relationships?relationships?

They occur when there are close, long-They occur when there are close, long-term interactions between two term interactions between two organisms! organisms! Parasitism (+, -)Parasitism (+, -) Mutualism- (+,+)Mutualism- (+,+) Commensalism (+,0)Commensalism (+,0)

PARASITISMPARASITISM(+,-)(+,-) One organism is harmed while the other One organism is harmed while the other

benefits.benefits. The __________ feeds on the The __________ feeds on the

_____________._____________. Usually parasitism does not result in Usually parasitism does not result in

the _____________________________ of the _____________________________ of the host. The parasite wants to keep the the host. The parasite wants to keep the host alive to feed off of it. host alive to feed off of it.

ParasiteHost

Immediate death

ParasitesParasites

A physician pulls a 19-foot tapeworm A physician pulls a 19-foot tapeworm from a man who has been treated with from a man who has been treated with deworming medication. The Worm deworming medication. The Worm Project helps to provide funds used for Project helps to provide funds used for the manufacture of 5-cent pills that the manufacture of 5-cent pills that

provide deworming treatment.provide deworming treatment.

Mutualism (+,+)Mutualism (+,+)

Is cooperative…. where both species Is cooperative…. where both species benefit!benefit!

Ex. Pollination, Cleaner WrasseEx. Pollination, Cleaner Wrasse

COMMENSALISM (+, 0)COMMENSALISM (+, 0) One benefits and the other is not affected. One benefits and the other is not affected.

Ex. Cattle egret birds eat the insects that are forced Ex. Cattle egret birds eat the insects that are forced out of their hiding places when buffalo move through out of their hiding places when buffalo move through the grass. the grass.

(who benefits?_______________________ (who benefits?_______________________ Who is not affected? _______________)Who is not affected? _______________)

Commensalism: RemorasCommensalism: Remoras