1. Ecological Principles Lecture 16

2. Ecology = the study of the interaction of organisms with their environments.

3. It involves understanding biotic and abiotic factors influencing the distribution and abundance of living things.

4. Biotic Factors Competitors Disease Predators Food availability Habitat availability Symbiotic relationships Abiotic Factors pH Temperature Weather conditions Water availability Chemical composition of environment nitrates, phosphates, ammonia, O 2, pollution

5. The word "ecology" coined from Greek word "oikos", which means "house" or "place to live”.

6. b b population growth b b competition between species b b symbiotic relationships b b trophic (=feeding) relationships b b origin of biological diversity b b interaction with the physical environment

7. The entire proportion of the earth that is inhabited by life. Includes communities and ecosystems. The Biosphere

8. Forest TundraSavanna Desert A major type of ecological community, determined largely by climate and dominate vegetation.

9. Population - an interbreeding group of individuals of a single species that occupy the same general area Community- the assemblage of interacting populations that inhabit the same area. Ecosystem- comprised of 1 or more communities and the abiotic environment within an area.

10. Environmental Gradient

11. Range of Tolerance

12. Zones of Intolerance

13. Optimum Range

14. Zones of Physiological Stress

15. Parameters that effect size or density of a population: Population (N) Emigration Immigration DeathsBirths Figure 1. The size of a population is determined by a balance between births, immigration, deaths and emigration BirthEmigration DeathImmigration

16. Generation 1 2 3 4 5 6 7 8 9 10 Population Size 1 2 4 8 16 32 64 128 256 512

17. Population Size 0 100 200 300 400 500 600 0123456789101112 Number of Generations Exponential Population Growth Unlimited resources

18. k k k = carrying capacity k is affected by: food production resource supply the env.’s ability to assimilate pollution exponential sigmoidal

20. b b limiting resources (e.g., food & shelter) b b production of toxic wastes b b infectious diseases b b predation b b stress b b emigration Increasing population density reduces resources and limits pop growth

21. b b severe storms and flooding b b sudden unpredictable severe cold b b spells b b earthquakes and volcanoes b b catastrophic meteorite impacts

23. Ecological niche = the "role" a species "plays" in the ecosystem. An organisms use of biotic and abiotic resources in its environment

24. Contrast the ecological niche with the "habitat" which is the physical environment in which the organism lives.

25. The ecological niche of a species, therefore includes: species’ habitat abiotic & biotic interactions

26. No two similar species occupy the same niche at the same time.

27. Extinction of one species

28. G. F. Gause (1934) tested competitive exclusion principle Constant food supply extinction

29. Resource partitioning: splitting the niche

30. Sympatric species consume slightly different resources or use resources in slightly different ways Insect-eating warblers

31. Character displacement: two similar species evolve in such a way as to become different from each other by accentuating their initial minor differences

32. Allopatric vs Sympatric populations

33. Allopatric populations: Similar beak morphologies and eat similar sized seeds

34. Avoids competition

36. b b Offset oscillations in the population sizes of the predator and prey b b Coevolution of predator and prey

39. C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy Animal cell

40. 6CO 2 + 6H 2 O + energy  C 6 H 12 O 6 + 6O 2

41. Carbon Cycle CARBON CYCLE

42. Humans affect the carbon cycle b b Burning fossil fuels moves carbon from the ground to the air. b b Cutting forests and burning fields moves carbon from organisms to the air. b b Today’s atmospheric carbon dioxide reservoir is the largest in the past 800,000 years. The driving force behind climate change

43. The phosphorus cycle

44. Humans affect the phosphorus cycle b b Mining rocks for fertilizer moves phosphorus from the soil to water systems. b b Wastewater discharge also releases phosphorus, which boosts algal growth and causes eutrophication. b b May be present in detergents Consumers should purchase phosphate-free detergents.

45. Nitrogen Cycle

46. Humans affect the nitrogen cycle b b Excess nitrogen leads to hypoxia in coastal areas. b b Synthetic fertilizers doubled the rate of Earth’s nitrogen fixation. b b Burning forests and fossil fuels leads to acid precipitation. b b Wetland destruction and increased planting of legumes has increased nitrogen-rich compounds on land and in water. b b Increased emissions of nitrogen-containing greenhouse gases b b Calcium and potassium in soil are washed out by fertilizers. b b Reduced biodiversity of plants adapted to low-nitrogen soils. b b Changed estuaries and coastal ecosystems and fisheries

47. Human inputs of nitrogen into the environment Fully half of nitrogen entering the environment is of human origin.

48. Eutrophication Mississippi River

49. Eutrophication runoff

50. Eutrophication

51. Gulf of Mexico Dead Zone 2006 Seamap Hypoxia Map

52. Eutrophication Fish kills

53. Biogeochemical Cycles

54. Ecological Succession The progressive change in the species composition of an ecosystem.

55. Ecological Succession Climax Stage New Bare Substrate Colonizing Stage Successionist Stage

56. PRIMARY SECONDARY b Growth occurs on newly exposed surfaces where no soil exists b Ex. Surfaces of volcanic eruptions b Growth occurring after a disturbance changes a community without removing the soil 2 types of succession

57. b b For example, new land created by a volcanic eruption is colonized by various living organisms

58. b b Disturbances responsible can include cleared and plowed land, burned woodlands

59. Mount St. Helens prior 1980

60. Mount St. Helens May 18, 1980 Sep. 24, 1980

61. Mount St. Helens Fireweed 1980 after eruption 2004 2012

62. Hanauma Bay Tuff Ring (shield volcano) Succession after Volcanic Eruption What organisms would appear first? How do organisms arrive, i.e., methods for dispersal? Volcanic eruption creates sterile environment

63. Mechanisms of Succession Facilitation Inhibition Tolerance Early species improve habitat. Ex. Early marine colonists provide a substrate conducive for settling of later arriving species. As resources become scarce due to depletion and competition, species capable of tolerating the lowest resource levels will survive. Competition for space, nutrients and light; allopathic chemicals. First arrivals take precedence.

64. r & K Selected Species Pioneer species- 1st species to colonize a newly disturbed area r selected Late successional species K selected low competitive ability short life span high growth rate higher maternal investment per offspring low reproductive output high reproductive output slow growth rate long life span high competitive ability r & K refer to parameters in logistic growth equation

65. Keystone Species A species whose presence in the community exerts a significant influence on the structure of that community.

66. Keystone predator hypothesis - predation by certain keystone predators is important in maintaining community diversity.

67. Paine’s study on Pisaster and blue mussels

68. Kelp Forests Keystone Species

70. Algal turf farming by the Pacific Gregory (Stegastes fasciolatus)

71. Antarctic Ecosystem krill

72. Ecological Succession on a Coral Reef

73. Successional Models and their Impacts b Case 1: No Disturbance (Competitive Exclusion Model) b Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model) b Case 3: Constant Strong Disturbance (Colonial Model)

74. Case 1: No Disturbance (Competitive Exclusion Model) As the reef becomes complex, organisms compete for space. Dominant organism outcompetes other species. Occurs in stable environments. Results in low species diversity. Highly protected patch reefs within lagoons or protected bays Deeper water

75. Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model) Storms and hurricanes allow for other species to move in Dominant species would not be allowed to reach competitive exclusion After each disturbance have a recovery period Area of high diversity

76. Case 3: Constant Strong Disturbance (Colonial Model) Constant exposure to disturbance Shallow environment High turnover of species r-selected species

77. Reef Case 3 Case 2 Case 1 Deep reef slope Reef slope beneath reef crest Near reef crest

78. Ecological Succession on a Coral Reef The Big Island

79. Ecological Succession on a Coral Reef

86. Successional Models and their Impacts

87. The definition of ecology means that: Ecosystems are often hard to study because: The "abiotic" part of the environment: The "Principle of Competitive Exclusion" predicts that: Questions

88. A species habitat may be thought of as its "_____" and its niche as its "_____.“ The removal of a keystone species may cause: A density independent factor that may affect a population is __________.