Species Interactions

Species InteractionsChapter 8, Sections 2

1Populations are limitedLimiting Factors : things in the environment that keep a population from growing out of control

Limiting factorsDensity-independent limiting factorsThese are not dependent on the size of the populationExamples: natural disasters, weather, human destruction of habitat

Limiting factorsDensity-dependent limiting factorsEffects of these depend on the size of the populationExamples: disease

Tasmanian devil population threatened by contagious disease called devil facial tumor disease

Limiting factorsDensity-dependent limiting factorsExample: Species InteractionsCompetitionPredationSymbiosis

NicheDefinition: the role of a species within an ecosystemNot just the habitat, but how it interacts with other organisms, too

6CompetitionDefinition: when two or more individuals or populations try to use the same limited resourceBoth are negatively affected by the interaction

7Types of competitionInterspecific competition competition between members of different speciesExample: plants compete for limited nutrients in the soil around them, light, water, space, etc.

8Interspecific competitionOrganisms have different adaptations to improve competitive edge a few examples:produce many offspring have extensive root systems that are efficient extremely fast growth rateallelopathy when a plant produces a chemical that prevents other plants from growing around it (black walnut, sunflowers, junipers)aggressive behavior

9Interspecific competitionExample: warblers different species of small songbirds that are similar in habit, compete for the same resources in trees

Cape May warblerBay-breasted warblerYellow-rumped warbler10Niche partitioningReduces interspecific competition by spatially dividing up resources

11Niche partitioningDue to competition, each species uses less of the niche than they are capable of usingExample: barnacles on p. 205

12Types of competitionIntraspecific competition members of the same species compete for food, mates, nesting sites, space, water, etc.Example:Wolves fighting for meatAlpha male will eat first

13Survival of the FittestIntraspecific competition can also be called survival of the fittest and is a driving force of evolutionThe individual that is best adapted to outcompete the others will survive and pass on its traits to its offspring

14PredationType of species interaction in which one organism (predator) feeds on another (prey)

15Predator/Prey relationshipsDoes the predator control the prey, or does the prey control the predator?

16Predator/Prey relationshipsMany adaptations have evolved due to predator/prey relationshipsExamples of adaptations of prey:camouflage, warning coloration, mimicry, chemical warfare, behavior17Camouflage: Hide

Butterfly that resembles a dead leaf18Warning Coloration: Advertise that you are not tastyBright colors advertise the fact that a prey is distasteful or poisonousEx: bees, poison arrow frogs, coral snake

19Behavior: Act tough and hang around with your friendsFlocking and mobbing by birds safety in numbers

20Mimicry: Look like someone elseBatesian mimicry when one palatable species mimics another that is harmful or distastefulEx: insects mimic waspsRight: A and B are stinging wasps, C-E are flies that mimic the wasps, F is a beetle that mimics the wasps

21MimicryMullerian mimicry when two or more species look alike and both are unpalatable, both benefit from the reinforcement to predators to avoid the pattern seenEx: Viceroy and Monarch are BOTH unpalatable

MonarchViceroy

Bluejay eats a monarch, then vomits, learns not to eat them22Combination: Mimicry and behavior

Butterfly with fake eyes on wings Urban mimicry

http://www.worth1000.com/contest.asp?contest_id=9307&display=photoshop24Urban mimicry

http://www.worth1000.com/contest.asp?contest_id=9307&display=photoshop25PredationExamples of adaptations of predators:Adaptations for capture- pursuit- ambush- trap- toolsAdaptations for killing- bite/claw- suffocate- poison

SymbiosisMeans living togetherThree types.

SymbiosisParasitism the parasite lives on or in the host Parasite benefits, host is harmed but not usually killed (this is different from predation where the prey is killed)

Wasp larvae living off a tomato hornworm

Adult deer tick on a personParasitismTwo categories when parasite lives on/in host: internal (e.g., tapeworms) external (e.g., ticks, fleas)Some parasites never come in contact with their hosts (e.g., cowbirds lay eggs in other birds nests and leave young to be raised by them)

SymbiosisMutualism both species benefit from the relationship

Benefit to clown fish: protection, eats food caught by anemones stinging cellsBenefit to anemone: clown fish keeps anemone cleans, provides nutrients in wastes, circulates water

Flowers and their pollinators both benefit as pollinators eat pollen and distribute it to other plantsMutualismPollination mutualism animals (bees, hummingbirds, butterflies) get food and plant gets pollen distributed directly to the right plantNutritional mutualism e.g., lichens algae (provides food) plus fungus (provides structure and absorption of nutrients, water)Gut inhabitant mutualism bacteria in termites gut or in humans gut help with digestion, get food

Mutualism lichens are made of fungus and algae, both benefitFungus: able to absorb water and nutrients from surface materialAlgae: carries out photosynthesis to make food (sugars)

SymbiosisCommensalism one species benefits, the other is neither hurt nor helped

Cattle egrets eat insects in the grass that are stirred up by the cattle

Cattle arent hurt or helped (but egrets may pick off a few parasites)CommensalismExample: epiphytes plants that live on other plants but do not hurt them

Resurrection fernTropical orchidsCoevolutionDefinition: process in which two species in a close relationship evolve in response to each other, usually to the benefit of one or both speciesExample: plants and pollinators have adaptations that help them in the relationship

Coevolution: Adaptations of pollinatorsButterfly tongueHummingbird beak

Coevolution: Adaptations of plantsThe flowers of Potentilla anserina prominently exhibit UV-meditated flower marks to aid visiting pollinators to reach their target.