1. Ecology

2. A. Definition The study of the interactions between organisms & organisms with their environment. I. Introduction B. Parameters 1. Abiotic – non-living. Like? 2. Biotic – living. Like? C. Levels of Organization

3. 1. Chemistry Subatomic ParticlesAtomsMoleculesMacro - Molecules 2. Biology TissuesOrgansOrganismsOrganellesCells PopulationCommunityEcosystemBiomeBiosphere 3. Ecology D. Distribution of Life

4. 1. Dispersal Limitations a. Not all areas are accessible – geographic isolation b. Each species has an actual and a potential range Potential range = area over which a species could survive if transplanted

5. 2. Behavior and Habitat Selection a. Animals mainly 3. Biotic Factors a. Disease b. Herbivory c. Absence of symbionts d. Lack of pollinators e. Competition

6. 4. Competition a. Factors i. Whenever the quantity of useful matter or energy falls below the level needed for the maximal growth of two or more organisms which must draw on the same supply, a contest begins. ii. The more similar the needs the greater the intensity of competition. iii. Competition from introduced species can shrink an organism’s actual range

7. b. Reasons? i. water ii. nutrients (minerals) iii. light iv. heat v. carbon dioxide, oxygen vi. space vii. pollinators Strategies????

8. 5. Abiotic Factors a. Limits i. Climate Varies from place to place, season to season. Each organism has an optimum environment needed for maximum growth.

9. Temperature & annual precipitation (climate vs. weather) are the most important factors determining the distribution of organisms on a global scale (biomes). ……Thus scientists predict that climate change may radically alter the distribution of organisms/ecosystems on earth.

10. Fig 52.10

11. Effects of climate on biogeography Climate varies with latitude because of differences in the angle of sunlight (seasons) Solar radiation creates wind currents, ocean currents, and precipitation (from evaporation)

12. Fig 52.4

13. Fig 52.3 & 5 Coriolis Effect

14. ii. Weather = Local climate Proximity to water, mountains E or W side of land mass S slope drier than N slope (thus different plant communities) iii. Precipitation = Microclimate Forest floor vs. canopy Under a log Within the litter layer

15. Fig. 52.13 Your ecosystem type: coastal temperate rainforest Fig 52.6

16. A. General Characteristics 1. Limits Locations of the earth’s biomes due to: a. Latitude – affects temperature, precipitation b. Positions of the continents 2. Structure One biome type may occur in different areas of the world but different plant species but same: a. Physiognomic structure – size; shape; types of organisms & their relation to each other & the physical Environment b. Due to convergent evolution – similar phenotypes due to similar selection pressures over time. Similar climate, soils, disturbance patterns,… II. Biomes

17. Fig. 52.9 B. Types

18. 1. Terrestrial (figure 52.12) a. Name Tropical rainforest b. Location Equatorial region c. Characteristics High average annual temp and precipitation, Lush, dense vegetation, Very diverse! Large vertical stratification due to competition for light (Canopy)

20. a. Name Savanna b. Location rimming Equatorial region c. Characteristics Grasslands with scattered trees, Large herbivores & predators, Rainy & dry season! Fire adapted

22. a. Name Desert b. Location Along Tropic of Cancer and Capricorn (23.5 o ) c. Characteristics < 30 cm of rain per year, High temperatures, CAM plants! Unique plants with adaptations to harsh environment

24. a. Name Chapparal b. Location Along rugged hilly salt water coasts c. Characteristics Evergreen shrubs, Hot dry summers, mild wet winters, Fire-dependent! – seeds germinated after fire, roots fire-resistant

26. a. Name Temperate Grassland b. Location Along 30 o N and S parallel, inland c. Characteristics No trees, Typically 4 seasons, Occasional fire, Fertile soils

28. a. Name Temperate deciduous forest b. Location Along 30 o N and S parallel coastal c. Characteristics Deciduous trees, 4 seasons (cold winter – dormant), Open forests

30. a. Name Coniferous Forest b. Location N hemisphere above 30 o or elevation c. Characteristics Evergreen trees (gymnosperms), Largest Biome on earth, 4 seasons, large amounts of snowfall

32. a. Name Tundra b. Location N hemisphere or high altitude c. Characteristics Permafrost – permanently frozen subsoil, Very cold, high winds, No trees or tall plants, 20% of land area on earth, Low annual precipitation

34. 2. Aquatic (Figure 52.16) a. Name Fresh water, relatively still - Lakes b. Location ??? c. Characteristics Thermocline, vertical zones, turbidity varies, oligotrophic versus eutrophic

36. a. Name Fresh moving water - Rivers and Streams b. Location ??? c. Characteristics Current, temperature and turbidity varies, vertical zones

38. a. Name Wetlands b. Location ??? c. Characteristics Temporary to semi-permanent, temperature and turbidity varies

40. a. Name Estuaries b. Location ??? c. Characteristics Salt fluctuations, temperature, depth, and turbidity varies

42. a. Name Oceanic b. Location Duh? c. Characteristics Salt fluctuations, temperature, depth, and turbidity varies, vertical zones

43. Fig 52.13

44. A. Characteristics I. Introduction Plant Population Ecology 1. Dispersion a. Patterns of Dispersion: i. Clumped – individuals in patches (ex. due to soil types, seed dispersal by animals) ii. Uniform – evenly spaced due to: Competition for resources or Allelopathy – plants secrete chemicals to inhibit nearby growth iii. Random – unpredictable; position of one individual cannot be predicted from position of another.

45. Allelopathic plantImpact Rows of black walnut interplanted with corn in an alley cropping system Reduced corn yield attributed to production of juglone, an allelopathic compound from black walnut, found 4.25 m (~14 ft) from trees Rows of Leucaena interplanted with crops in an alley cropping system Reduced the yield of wheat and turmeric but increased the yield of maize and rice Lantana, a perennial woody weed pest in Florida citrus Lantana roots and shoots incorporated into soil reduced germination and growth of milkweed vine, another weed Sour orange, a widely used citrus rootstock in the past, now avoided because of susceptibility to citrus tristeza virus Leaf extracts and volatile compounds inhibited seed germination and root growth of pigweed, bermudagrass, and lambsquarters Red maple, swamp chestnut oak, sweet bay, and red cedar Wood extracts inhibited lettuce seed as much as or more than black walnut extracts Eucalyptus and neem treesA spatial allelopathic relationship if wheat was grown within 5 m (~16.5 ft) Chaste tree or box elder Leachates retarded the growth of pangolagrass, a pasture grass, but stimulated the growth of bluestem, another grass species MangoDried mango leaf powder completely inhibited sprouting of purple nutsedge tubers. Tree of heaven Ailanthone, isolated from the tree of heaven, has been reported to possess non-selective postemergence herbicidal activity similar to glyphosate and paraquat Rye, fescue, and wheat Allelopathic suppression of weeds when used as cover crops or when crop residues are retained as mulch BroccoliBroccoli residue interferes with growth of other cruciferous crops that follow Jungle riceInhibition of rice crop Forage radishCover crop residue suppression of weeds in the season following the cover crop Jerusalem artichokeResidual effects on weed species Sunflower and buckwheatCover crop residues reduced weed pressure in fava bean crop

46. Clumped lupine

47. Uniform dispersal of sagebrush

48. Random trees

49. 2. Population Size a. Demography = study of factors that affect the growth & decline of populations i. Increase by reproduction, immigration ii. Decrease by death, emigration Change in Population size = (B + I) – (D + E) If B – D = 0, then zero population growth

50. Fig. 53.9

51. b. Life History = events from birth, through Reproduction, to death i. Dormancy, germination, growth, reproduction, dispersal, death ii. Trade-offs between investments in reproduction & survival when there are limited resources

52. Controls at every stage of life history Seeds washed away, eaten, decomposed Dormancy (seed bank) Seeds rain from mature plants seedling growth mature plant reproduction death New resources available, perfect growing conditions, freedom from disease, competition, drought Herbivory, disease, competition, drought, flood, freeze

53. 3. Growth Occurs when resources are abundant or when an important constraint has be removed. Ex. Recolonization after fire Represents a doubling of the population in a specified time. a. Patterns i. Exponential The j-shaped curve Time Number of Individuals

54. Steady increase followed by a plateau due to ????. i. Logistical Time Number of Individuals Initial population density New population density Logistic growth

55. b. Limits Biotic Potential (r) i. Intrinsic Factors Plenty of food, living space, and other resources. No competition Habitat is free of predators and pathogens. Density & competition for resources will cause reproduction rates to decline or stabilize.

56. Any essential resource that is in short supply is a limiting factor on population growth. Food (Why?) micro-nutrients refuge from predators living space pollution-free environment

57. ii. Environmental resistance affects the number of individuals of a given species that can be sustained indefinitely in a particular area. K Time Number of Individuals Introduction Colonization Naturalization

58. iii. Carrying Capacity (K) The maximum population size a particular area or habitat can support at a particular time. Is not fixed - K may decrease when a large population damages or depletes its own resource supply.

59. 4. Control i. Density Independent Control a. Factors ii. Density Dependent Control

60. 5. Adaptations a. At low density, population is limited only by intrinsic rate of growth (r) b. At high density, population is limited by carrying capacity (K) c. r versus K strategy d. Competitive, Ruderals, or Stress Tolerant

61. i. r - selection Disturbance creates low-density conditions, frees resources (fire, flood, volcano) Biotic potential (r) limits population size Adaptations that are successful for these conditions: –Produce large # of seeds fast –Wind dispersal of seed –Plants grow & flower quickly (annuals) –Few chemical/mechanical defenses

62. ii. K-selection High density, population size close to K Not much “new” space – competition for resources Adaptations that are successful for these conditions: –Perennial –Fewer, larger seeds –Defenses against herbivores, pathogens –Adaptations to shading, poor soils

63. K & r selected species exist together because small- scale disturbances create space (exposed soil) for r species (colonizers) –Ex. Downed tree, badger holes, grazing disturbance

65. I. Background 1. Groups of organisms of different species (populations) living and interacting with each other and the habitat A. Definition Plant Community Ecology

66. B. Hypothesis of Structure 1. Question? Are plant communities a real entity in nature? Why are certain species found together? 2. Hypotheses: a. Individualistic hypothesis - Gleason i. Species are found together in nature because they have similar abiotic requirements ii. No distinct boundaries between communities iii. Each species distributed along its tolerance range iv. Thus communities change continuously along a gradient

67. b. Integrated Hypothesis - Clements i. Plant communities function as a real, integrated unit. ii. Plant species found together because of interactions with each other & the rest of the ecosystem. iii. Thus species are clustered into discrete communities with definite distribution boundaries.

68. Which is correct?

69. c. So? Individualistic/Continuum “more correct”, but evidence of both – some sharp boundaries due to dramatic environmental changes.

70. II. Characteristics of communities A. Diversity – composed of: 1. Richness – the total number of species in the community 2. Evenness – the relative abundance of species in the community (some dominant, some rare) a. Relative abundance = # individuals of species X divided by total # of individuals in the community

71. Which community is more diverse?? Fig 54.10

72. Fig. 54.10

73. B. Factors a. Each species has a tolerance range – range of conditions under which it can survive & reproduce b. Climate – temp, moisture c. Soil – types, pH d. Latitude & Altitude 1. Abiotic

74. e. Disturbance i. Decrease or total elimination of the biotic components of the habitat ii. Results: decrease in biomass, diversity iii. Natural events – fire, flood, volcano, avalanche iv. Human-caused – herbicides, roads, development, logging, grazing, farming, mining v. Opens resources, creating opportunities for new species, different composition vi. All communities have evolved with some type of disturbance, varying in type, frequency, & severity

75. vii. Small-scale, frequent disturbance Creates patches within the ecosystem Thus increase in diversity Ex. Trees downed in wind storm Can prevent large-scale disturbance – fire! Ex. Yellowstone fire of 1988 Fire suppression in fire-dependent ecosystem caused massive, stand-replacing fire

78. viii. Human Caused Example Cheatgrass – wildfire cycle Overgrazing in ecosystem that did not evolve with large herbivores Cheatgrass introduction Decrease in fire frequency (100 yr to 5 year cycle) Conversion of ecosystem with tremendous loss of Diversity These types of problems creating mass extinction worldwide.

85. 2. Biotic a. The plant itself i. Can modify the environment ii. Modifications can be +, -, or neutral to the plant iii. Benefit ex: beech/oak forest creates shade needed for other young beech & oak to grow iv. Detriment ex: pine forest creates shade but pines need lots of light to grow (succession)

86. b. Other plant species i. Theory of competitive exclusion: When two species compete for the same limiting resource (occupy the same niche), the species that is less adapted will be excluded from the community by the superior competitor. If this theory is true, then actually very little competition in nature, because each plant occupies a niche.

87. low high Light intensity  Species Abundance Species A Species B A B C D

88. Resource partitioning creates niches A BCD Species A Species B

89. ii. Niche A set of conditions exploited best by only one species Includes all aspects of a species’ use of biotic & abiotic resources (microclimate, rooting zone, pollinators, etc.) A species’ role in the ecosystem.

90. c. Other (non-plant species) i. Mutualism – both organisms benefit Examples: Mycorrhizal fungi, N-fixing bacteria in root nodules Pollinator gets nectar and plant gets pollen transfer Animals eat fruit (nutrition) and seeds are dispersed Acacia trees get defense from herbivores & ants get home, food

92. ii. Commensalism – one species benefits & other is not affected Bird nests in trees, seeds stuck on animal fur iii. Competition – both harmed iv. Predation – one harmed, other benefits Herbivory Pathogens

93. Predation or the need to keep your wits about you?

94. C. Controls on community structure a. Dominant species = species with the highest abundance or biomass in the community i. Best species among all species in the community at exploiting the limiting resource ii. Controls occurrence & distribution of other species iii. If eliminated, other species take over Example: Douglas fir

95. b. Keystone species i. Control community structure by their ecological role ii. If eliminated, drastic change in community structure or composition Example Sea otter – reduction in populations caused boom in sea urchin population, destroying kelp forests (drastic decline in diversity)

96. Succession

97. III. Succession A. Definition 1. Changes in community structure & composition over time following a disturbance 2. Species thriving on a site are gradually replaced by other species. 3. Species replacement continues until the composition of species becomes relatively steady under prevailing climatic conditions & disturbance regimes (dynamic equilibrium, not climax).

98. B. Types 1. Primary Succession a. Characteristics i. New area of mineral rock – no soil yet (volcano, glacier retreat)

99. b. Sequence: i. Lichens & mosses colonize bare rock ii. As these decay, acids weather the rock & primitive soil forms iii. Pioneer plants establish (r-selected or Stress tolerant) iv. Pioneers replaced by K-selected (Ruderal and Competitive)

100. c. The Nature of Pioneer Species i. Adapted to growing in habitats that cannot support most species: intense sunlight, wide swings in temperature, moisture deficits. ii. Typically small plants, short life cycles, producing an abundance of small seeds which are quickly dispersed (wind & water) iii. Can grow in N-poor soil because of their mutualistic interactions with nitrogen-fixing bacteria.

101. Example of primary succession: glacial retreat

105. Alders & cottonwoods dominate

106. Spruce enter forest and replace alders/cottonwoods

107. Hemlock slowly replace Spruce. Hemlock is “climax”

108. iv. Facilitation Improve the living conditions for other species, setting the stage for their own replacement. Accumulation of their wastes and remains adds volume to the soil and enriches it with nutrients that allow other species to take hold.

109. 2. Secondary Succession a. Characteristics i. Plant community is destroyed but soil remains while new soil exposed ii. Examples? abandoned farm fields, clear cuts, wind storms, fire. iii. Typical progression: small herbs & grasses  shrubs  trees

110. b. Pioneer species i. r-selected (stress tolerant) (species move in first when competition is low (low density). ii. Sometimes these opportunistic species (especially invasive weeds!) inhibit the growth of the native climax species changing the structure and type of climax community forever. Ex. cheatgrass