2Review of Biotic and Abiotic Factors Ecosystems are influenced by a combination of biological and physical factors.Biotic factorsinclude all the living things with which an organism might interact.Abiotic FactorsPhysical, or nonliving, factors that shape ecosystems.
3Habitat and Niche Habitat all aspects of the area in which an organism lives (includes both biotic and abiotic).Habitats may change or disappear due to natural causes or interference by man.
4Habitat and Niche Niche the role or place and position a species has in its environment.An ecological niche includes all of the factors that a species needs to survive, stay healthy, and reproduce.foodabiotic conditionsbehavior
5Habitat and NicheWhy do you think no two species can share the same niche.One species is better suited to the niche and the other will either be pushed out or become extinct.
6Community Interactions When organisms live together in ecological communities, they interact constantly.Community interactions include:CompetitionPredationSymbiosis
7Community Interactions Competition:occurs when two organisms fight for the same limited resource.Direct competition in nature often results in a winner and a loser—with the losing organism failing to survive.
8How species avoid Competition The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree.
9Community Interactions PredatorPredation:occurs when one organism captures and eats another.Prey
10Community Interactions Symbiosis:Any relationship in which two species live closely togetherIncludes:mutualismcommensalismparasitism
11Community Interactions Mutualism:both species benefit from the relationship.
12Community Interactions Commensalismone member of the association benefits and the other is neither helped nor harmed.Human Our eyelashes are home to tiny mitesthat feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle.Demodicids Eyelash mites find all they need to survive in the tiny folliclesof eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope.+Organism benefitsØOrganism is not affectedCommensalism
13Community Interactions Parasitismone organism lives on or inside another organism and harms it.Organism benefits_Organism is not affectedHornworm caterpillarThe host hornworm will eventually die as its organs are consumedby wasp larvae.Braconid waspBraconid larvae feed on their host and release themselves shortly before reachingthe pupae stage of development.Parasitism+
14Ecological Succession Succession occurs following a disturbance in an ecosystem and regenerates or creates a community after a disturbance.a sequence of biotic changesdamaged communities are regeneratednew communities arise in previously uninhabited areas
15Ecological Succession There are two types of succession.primary succession — started by pioneer species
16Ecological Succession There are two types of succession.secondary succession — started by remaining species