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Population Ecology

Explore the dynamics of populations through spatial distributions, complexities of dispersion, competition modeling, empirical tests, and the impact of interactions like competition and predation on species coexistence and growth.

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Population Ecology

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  1. Population Ecology Populations are groups of potentially reproducing individuals in the same place, at the same time, that share a common gene pool. I. Spatial Distributions A. Dispersion

  2. I. Spatial Distributions A. Dispersion - Regular

  3. I. Spatial Distributions A. Dispersion - Regular - intraspecific competition - allelopathy - territoriality

  4. I. Spatial Distributions A. Dispersion - Clumped - patchy resource - social effects

  5. I. Spatial Distributions A. Dispersion - Random - canopy trees, later in succession

  6. I. Spatial Distributions A. Dispersion - Complexities - can change with development. Seedlings are often clumped (around parent or in a gap), but randomness develops as correlations among resources decline. regular can develop if competition becomes limiting.

  7. I. Spatial Distributions A. Dispersion - Complexities - can change with development. Seedlings are often clumped (around parent or in a gap), but randomness develops as correlations among resources decline. regular can develop if competition becomes limiting. - can change with population, depending on resource distribution.

  8. I. Spatial Distributions A. Dispersion - Complexities - can change with development. Seedlings are often clumped (around parent or in a gap), but randomness develops as correlations among resources decline. regular can develop if competition becomes limiting. - can change with population, depending on resource distribution. - varies with scale. As scale increases, the environment will appear more 'patchy' and individuals will look clumped.

  9. Species Interactions

  10. II. COMPETITION B. Modeling Competition 1. Intraspecific competition

  11. II. COMPETITION B. Modeling Competition 2. Interspecific competition The effect of 10 individuals of species 2 on species 1, in terms of 1, requires a "conversion term" called a competition coefficient (α).

  12. II. COMPETITION A. Modeling Competition B. Empirical Tests of Competition

  13. B. Empirical Tests of Competition 1. Gauss P. aurelia vs. P. caudatum P. aurelia outcompetes P. caudatum.

  14. B. Empirical Tests of Competition 1. Gauss P. aurelia vs. P. bursaria ):

  15. B. Empirical Tests of Competition 1. Gauss P. aurelia vs. P. bursaria: coexistence ):

  16. B. Empirical Tests of Competition 1. Gauss Why do the outcomes differ? - P. aurelia and P. caudatum feed on suspended bacteria - they feed in the same microhabitat on the same things. P. bursaria feeds on bacteria adhering to the glass of the culture flasks. ):

  17. B. Empirical Tests of Competition 1. Gauss Why do the outcomes differ? - P. aurelia and P. caudatum feed on suspended bacteria - they feed in the same microhabitat on the same things. P. bursaria feeds on bacteria adhering to the glass of the culture flasks. - Gauss concluded that two species using the environment in the same way (same niche) could not coexist. This is the competitive exclusion principle. ):

  18. B. Empirical Tests of Competition 1. Gauss 2. Park • Competition between two species of flour beetle: Tribolium castaneum and T. confusum. Tribolium castaneum

  19. B. Empirical Tests of Competition 1. Gauss 2. Park Competitive outcomes are dependent on complex environmental conditions Basically, T. confusum wins when it's dry, regardless of temp.

  20. B. Empirical Tests of Competition 1. Gauss 2. Park Competitive outcomes are dependent on complex environmental conditions But when it's moist, outcome depends on temperature

  21. B. Empirical Tests of Competition 1. Gauss 2. Park 3. Connell ): Intertidal organisms show a zonation pattern... those that can tolerate more desiccation occur higher in the intertidal.

  22. 3. Connell - reciprocal transplant experiments Fundamental Niches defined by physiological tolerances ): increasing desiccation stress

  23. 3. Connell - reciprocal transplant experiments Realized Niches defined by competition ): Balanus competitively excludes Chthamalus from the "best" habitat, and limits it to more stressful habitat

  24. II. COMPETITION A. Modeling Competition B. Empirical Tests of Competition C. Competitive Outcomes: - Reduction in organism growth and/or pop. size (G, M, R) - Competitive exclusion (N = 0) - Reduce range of resources used = resource partitioning. - If this selective pressure continues, it may result in a morphological change in the competition. This adaptive response to competition is called Character Displacement ):

  25. Character Displacement

  26. III. Predation A. Predators can limit the growth of prey populations

  27. A. Predators can limit the growth of prey populations

  28. Kelp and Urchins In 1940's:

  29. Kelp and Urchins In 1940's:

  30. Moose and Wolves - Isle Royale

  31. Moose and Wolves - Isle Royale 1930's - Moose population about 2400 on Isle Royale

  32. 1930's - Moose population about 2400 on Isle Royale 1949 - Wolves cross on an ice bridge; studied since 1958

  33. 1930's - Moose population about 2400 on Isle Royale 1949 - Wolves cross on an ice bridge; studied since 1958

  34. V. Dynamics of Consumer-Resource Interactions A. Predators can limit the growth of prey populations B. Oscillations are a Common Pattern

  35. IV. Mutualism Trophic Mutualisms – help one another get nutrients

  36. Trophic Mutualisms – help one another get nutrients 1-Esophagus2-Stomach3-Small Intestine4-Cecum (large intestine) - F5-Colon (large intestine)6-Rectum Low efficiency - high throughput...

  37. Trophic Mutualisms – help one another get nutrients

  38. Trophic Mutualisms – help one another get nutrients

  39. Trophic Mutualisms – help one another get nutrients

  40. Trophic Mutualisms – help one another get nutrients

  41. Trophic Mutualisms – help one another get nutrients

  42. Trophic Mutualisms – help one another get nutrients

  43. Defensive Mutualisms – Trade protection for food

  44. Defensive Mutualisms – Trade protection for food

  45. Defensive Mutualisms – Trade protection for food Acacia and Acacia ants

  46. Cleaning Mutualisms – Trade cleaning for food

  47. Dispersive Mutualisms – Trade dispersal for food Create floral ‘syndromes’ – suites of characteristics that predispose use by one type of disperser

  48. Dispersive Mutualisms – Trade dispersal for food

  49. Dispersive Mutualisms – Trade dispersal for food Not mutualism (commensal or parasitic)

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