2Interpret interactions among organisms exhibiting predation, parasitism, commensalism and mutualism Identify and illustrate that long-term survival of a species is dependent on a resourceInvestigate and explain the interactions in an ecosystem including food chains, food webs and food pyramids
3Population Community Ecosystem Biotic factors: living parts of the ecosystem (ex: trees, birds, etc.)Abiotic factors: non-living parts of the ecosystem (ex: rocks, water, etc.)Population Community EcosystemPopulation: group of organisms of the same species living togetherCommunity: groups of populations living in the same areaEcosystems: community + all the non-living surroundings
4Name the Biome Temperate Forest Desert Tundra Grasslands Tropical RainforestTiaga
5Predator Prey Predators feed on other organisms. Prey are the organisms that get eaten.The prey population needs to be larger than the predator population. As the prey population increases, the predator population increases. If the prey population decreases, the predator population decreases.Predation keeps population size within the limits of available resources.
6SymbiosisSymbiosis: means “living together”--there are 3 types of symbiotic relationshipsParasitism: the host is harmed and the parasite benefits (ex: human and a tapeworm)Commensalism: one organism is not harmed nor benefited and the other organism benefits (ex: tree and a bird)Mutualism: both organisms benefit (ex: clown fish and an anemone)Host ParasiteOrganism Unaffected Organism BenefitedOrganism Benefited Organism Benefited
7Grass Insect Bird Hawk Food ChainFood Chain: represents the flow of energy in an ecosystem; the arrows represent the direction of energy flow and are called trophic levels. There are usually 3-4 trophic levels in a food chain but no more than 5 levelsGrass Insect Bird Hawk(plant) (herbivore) (carnivore) (carnivore)Producer: organisms that undergo photosynthesis (grass); also called autotrophsConsumer: organisms that must eat producers/consumers; also called heterotrophsPrimary consumer: these organisms eat the producers (insects)Secondary consumer: these organisms eat the primary consumers (bird)Tertiary consumer: these organisms eat the secondary consumers (hawk)
8Food Chain Cont.Scavengers: organisms that feed on dead animals (ex: vultures)Decomposers: organisms that break down dead organic material (ex: fungi)Herbivores: eat only producersCarnivores: eat only consumersOmnivores: eat producers and consumers
10PyramidsThere must always be more prey than predators because the predators can not use all the energy that is consumed from the prey. The lower an organism is on the food chain, the higher the numbers of these organisms. The more organisms there are at a trophic level, the more mass the group of organisms has.Energy PyramidNumber PyramidBiomass PyramidBirds10 kgFox1 kgGrasshoppers100 kgGrasses1000 kgGrasses100%Grasshoppers10%Birds1%Fox0.1%
11Biological Magnification If a chemical or toxin (ex: DDT) enters the food chain at a low level (ex: grass) the amount of that chemical increases as you move up the food chain.