organism population community Community Ecology ecosystem biosphere AP Biology Community Ecology . Community all the organisms that live together in a place . interactions To answer: In what way do the . Community Ecology populations interact? study of interactions among all populations in a common environment AP Biology Niche . An organism’s niche is its ecological role habitat = address vs. niche = job High tide Competitive Exclusion If Species 2 is removed, then Species 1 will occupy Species 1 whole tidal zone.Low tide But at lower depths Species 2 out-competes Species 1, Chthamalus sp. excluding it from its potential (fundamental) niche. Species 2 Fundamental Realized AP Biology niches niches Semibalanus sp. Ecological niche: the sum total of an organism’s use of abiotic/biotic resources in the environment . Fundamental niche = niche potentially occupied by the species . Realized niche = portion of fundamental niche the species actually occupies High tide High tide Chthamalus Chthamalus Balanus realized niche Chthamalus Balanus fundamental niche realized niche Ocean Low tide Ocean Low tide AP Biology Realized - max. range that a species has occupied in Interspecificreality due Interactions to competition/other factors Potential/Fundamental Niche - max. range that a I) Competitionspecies (can-/- occupy) Realized and Potential Niche AP Biology Niche & competition . Competitive Exclusion No two similar species can occupy the same niche at the same time AP Biology No two organisms can have the same ecological niche Principle of Competitive Exclusion AP Biology And Resource Partitioning No two organisms can have the same ecological niche - Competitive Exclusion https://www.youtube.com/watch?v=rZ_up40FZVw Competitive exclusion https://www.youtube.com/watch?v=0w5-UfEi470 Resource partitioning QuickTime™ and a QuickTime™ and a TIFF (Uncompressed) decompressor TIFF (Uncompressed) decompressor are needed to see this picture. are needed to see this picture. Character Displacement - species living close together differ more in traits than AP Biology those living far away Resource partitioning Reduce competition through microhabitats “the ghost of competition past” AP Biology • Interspecific competition: resources are in short supply ▫ Species interaction is -/- • Competitive exclusion principle: Two species cannot coexist in a community if their niches are identical. ▫ The one with the slight reproductive advantage will eliminate the other • Resource partitioning: differences in niches that enable similar species to AP Biologycoexist Interspecific interactions . Symbiotic interactions competition (-/-) . compete for limited resource . competitive exclusion! predation / parasitism (-/+) mutualism (+/+) . lichens (algae & fungus) commensalism (+/0) . barnacles attached to whale AP Biology Symbiosis mutualism +/+ …not very funny for a clown fish commensalism +/0 APpredation Biology +/- competition -/- What relationship is this? AP Biology Predation drives evolution . Predators adaptations locate & subdue prey . Prey adaptations elude & defend Predation provides a strong selection horns, speed, coloration pressure on both prey & predator spines, thorns, toxins AP Biology Anti-predator adaptations . Hide from predators avoid detection camouflage . Warn predators advertise how undesirable you are as prey aposematic coloration . apo = away & sematic = sign/meaning . Batesian mimicry . Mullerian mimicry AP Biology Interspecific Interactions 1)Cryptic . Predation -ways to avoid it Coloration = camouflage AP Biology Defense mechanisms . Camouflage cryptic coloration whipporwill frog lizard AP Biologylizard toad Interspecific Interactions . Avoiding Predation 2)Aposematic Coloration= warning coloration AP Biology Common warning coloration . Aposematic species come to resemble each other black, red, orange & yellow means: DON’T EAT ME! AP Biology Interspecific Interactions . Avoiding Predation 3)Batesian Mimicry – harmless species mimics harmful AP Biology Convergent evolution Mimicry palatable or harmless species Batesian mimicry mimics a harmful model green parrot snake Hawkmoth larva puffs up to hawkmoth larvae look like poisonous snake AP Biology Convergent evolution Batesian mimicry Monarch male Viceroy male poisonous edible Which is the mothfly vs. vs. the the bee? bee? AP Biology fly bee moth bee Interspecific Interactions . Avoiding Predation 4)Mullerian Mimicry – 2 unpalatable species resemble each other. Why? AP Biology Mullerian mimicry two or more protected species look like each other cuckoo bee yellow jacket - group defense? Mullerian mimicry AP Biology - predators may evolve innate avoidance What kind of mimicry? Coral snake King snake is not is poisonous Red on yellow, poison fellow; red on black, safe from attack AP Biology Interspecific Interactions . Predation (+/-) Parasitism is a type of predation “Scientists have discovered a way to kill the malaria parasite - by targeting its sweet tooth.” –BBC News AP Biology Interspecific Interactions . Predation (+/-) Parasitism AP Biology Interspecific Interactions . Predation (+/-) Parasitism - types: a) Ectoparasite b) Endoparasite c) Parasitoidism- Nasonia AP Biology AP Biology Interspecific Interactions III) Mutualism (+/+) Coevolution- change in one species affects evolution of another species Ex. Nitrogen fixing bacteria in the root of legumes, bees and flowers, cellulose digesting bacteria in gut of cows AP Biology Coevolution in Community . Predator-prey relationships . Parasite-host relationships . Flowers & pollinators APLong Biology term evolutionary adjustments between species Interspecific Interactions . Commensalism (+/0) One benefits, one neithergains/loses: dung beetle, birds on cattle, Nemo AP Biology and anemone! Symbiosis - term describes ‘living together’ Predation (+/-) CommensalismAP Biology (+/0) Mutualism (+/+) Trophic Structures . The trophic structure of a community is determined by the feeding relationships between organisms. Trophic levels = links in the trophic structure . The transfer of food energy from plants herbivores carnivores decomposers is called the food chain. AP Biology What limits the length of a food chain? . Inefficiency of energy transfer along chain . Long food chains less stable than short chains Fig. 53.10 AP Biology . Dominant species: has the highest biomass or is the most abundant in the community . Keystone species: exert control on community structure by their important ecological niches Loss of sea otter increase sea urchins, destruction of kelp forests Grizzly bear (transfer nutrients from sea land by salmon diet) AP Biology Prairie dogs (burrows, soil aeration, trim vegetation) Dominant species - highest biomass (sum of weight of all individuals in a population) Sugar maple - shade out other plants and take in most water What happens if dominant species is removed? AP BiologySomething else takes over usually Can a species be non-dominant and still control the community? . Sea star preys on mussels . Mussels eat algae/small invertebrates . Sea star’s absence results in decrease of algae/invertebrates in the community AP Biology Keystone species Pisaster ochraceous . Influential ecological role exert important regulating effect on other species in community Sea star keystone species increases diversity increases diversity diversity decreases in habitat mussels out-compete other species AP Biology Washington coast Keystone species Sea otter is a keystone predator in North Pacific What is the impact of the Orca whale? AP Biology Keystone species Beaver is a keystone species in Northeast & West damsAP Biology transform flowing streams into ponds creating new habitat Disturbances influences species diversity and composition . A disturbance changes a community by removing organisms or changing resource availability (fire, drought, flood, storm, human activity) . Ecological succession: transitions in species composition in a certain area over ecological time AP Biology Disturbances – environmental changes (volcanoes, fires…..!) Density Independent Factor - keeps population size in check; dominant species growth is curbed AP Biology Non-equilibriumFig. 53.16 Succession – Transition in Species Composition Over Ecological Time; Predictable order of species (first - easily dispersed species; later - superior competitors) 1980 1981After Before AP Biology Ecological succession . Sequence of community changes transition in species composition over time . years or decades usually after a disturbance Mt.AP St.Biology Helens Succession of species pioneer species compete well in high sunlight lichens & mosses grasses more shade tolerant species climax forest shade tolerant species stable community AP Biology bushes & small trees trees What causes succession? . Tolerance early species are weedy r-selected tolerant of harsh conditions . Facilitation & Inhibition early species facilitate habitat changes . change soil pH . change soil fertility . change light levels allows other species to out-compete AP Biology Primary succession . Begins with virtually lifeless area without soil, then… make bacteria soil lichens & { mosses grasses shrubs trees AP Biology Primary Succession . Plants & animals invade where soil has not yet formed Ex. colonization of volcanic island or glacier AP Biology Primary Succession Soil has been A) Glaciation removed B) Volcanic Lava Flows C) Volcanic Explosions D) Faulting raising sea floor AP Biology Primary Succession -soil ‘gonner’ Soil has been removed . by volcano 1) Short