Presentation on theme: "What Shapes an Ecosystem?. Review of Biotic and Abiotic Factors Ecosystems are influenced by a combination of biological and physical factors. Biotic."— Presentation transcript:
Review of Biotic and Abiotic Factors Ecosystems are influenced by a combination of biological and physical factors. Biotic factors –include all the living things with which an organism might interact. Abiotic Factors –Physical, or nonliving, factors that shape ecosystems.
Habitat 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.
Habitat 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. –food –abiotic conditions –behavior
Habitat and Niche Why 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.
Community Interactions When organisms live together in ecological communities, they interact constantly. Community interactions include: –Competition –Predation –Symbiosis
Community 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.
How species avoid Competition The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree.
Community Interactions Predation: –occurs when one organism captures and eats another. Predator Prey
Community Interactions Symbiosis: –Any relationship in which two species live closely together –Includes: –mutualism –commensalism –parasitism
Community Interactions Mutualism: –both species benefit from the relationship.
Community Interactions Commensalism –one member of the association benefits and the other is neither helped nor harmed. Human Our eyelashes are home to tiny mites that 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 follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. + Organism benefits + Ø Ø Organism is not affected Commensalism
Community Interactions Parasitism –one organism lives on or inside another organism and harms it. Organism benefits 0 _ Organism is not affected Hornworm caterpillar The host hornworm will eventually die as its organs are consumed by wasp larvae. Braconid wasp Braconid larvae feed on their host and release themselves shortly before reaching the pupae stage of development. _ Parasitism + 0
Ecological Succession Succession occurs following a disturbance in an ecosystem and regenerates or creates a community after a disturbance. –a sequence of biotic changes –damaged communities are regenerated –new communities arise in previously uninhabited areas
Ecological Succession There are two types of succession. primary succession — started by pioneer species
Ecological Succession There are two types of succession. –secondary succession — started by remaining species