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Limiting Factors in Populations

Limiting Factors in Populations. Biology I Miss Hanna. Limiting Factors. Factor that causes population growth to decrease Competition Predation Parasitism and disease Drought and climate extremes Human disturbances. Density-dependent Factors.

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Limiting Factors in Populations

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  1. Limiting Factors in Populations Biology I Miss Hanna

  2. Limiting Factors • Factor that causes population growth to decrease • Competition • Predation • Parasitism and disease • Drought and climate extremes • Human disturbances

  3. Density-dependent Factors • Limiting factor that depends on population size

  4. Types of Density-dependent Factors • Competition • Overcrowding causes organisms to compete for food, water, space and sunlight • Predation • Predator-prey relationship • Parasitism and Disease • Parasites take nutrients from host, weakening host, spreading disease or death

  5. Density-Independent Factors • Affects all populations in similar ways, regardless of population size • Unusual weather • Natural disasters • Seasonal cycles • Human activities

  6. Changes in Ecosystems:Ecological Succession

  7. Definition: • Succession: Series of predictable changes that occur in a community over time • Two types of changes: • Primary • Secondary

  8. Primary Succession • Begins in a place without any soil • Sides of volcanoes • Landslides • Flooding • Starts with the arrival of lichens- do not need soil to survive • Called PIONEER SPECIES

  9. http://botit.botany.wisc.edu http://www.saguaro-juniper.com/

  10. Bare Rock to Soil • Lichens, the forces of weather and erosion break down rocks into smaller pieces making SOIL from barren rock

  11. http://www.life.uiuc.edu

  12. Lichens and Mosses • Simple plants like mosses and ferns can grow in the new soil http://www.uncw.edu http://uisstc.georgetown.edu

  13. Grassland • The soil layer thickens, and grasses, wildflowers, and other plants begin to take over http://www.cwrl.utexas.edu

  14. Shrubland • These plants die, add more nutrients to the soil • Shrubs and trees can survive now http://www.rowan.edu

  15. Young Forest • Insects, small birds, and mammals move in • Small trees give way to large trees http://p2-raw.greenpeace.org

  16. http://www.geo.arizona.edu

  17. Steps of Succession • Lichens mosses and Ferns  grasses shrubs  young forest

  18. Secondary Succession • Begins in a place that has soil and was once the home of living organisms • Occurs faster and has different pioneer species than primary succession • Example: after forest fires

  19. Secondary Succession

  20. http://www.ux1.eiu.edu

  21. http://www.agen.ufl.edu

  22. Climax Community • A stable group of plants and animals that is the end result of the successionprocess • Does not always mean big trees • Grasses in prairies • Cacti in deserts

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