1 Principles of Environmental Science Inquiry and Applications Third Edition Cunningham Chapter 3 Lecture Outlines* *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Populations, Communities, and Species Interaction Chapter 3

Figure 03.CO

4 Outline: Critical Factors and Tolerance Limits Adaptation and Natural Selection Speciation Taxonomy Ecological Niche Species Interaction Population Growth Community Properties and Structure Succession

5 Critical Factors and Tolerance Limits 1. Critical Factor - Single factor in shortest supply relative to demand is a critical determinant in species distribution. Ex. Food, water, sunlight  2. Tolerance Limits refer to minimum and maximum levels beyond which a particular species cannot survive or reproduce. - Many species exhibit tolerance limits that are more critical for the 3. young than for the 4. adults.

6 Tolerance Limits

7 Adaptation 5. Adaptation - Process where species acquire traits that allow them to survive in their environments.  Limited range of physiological modifications.  Inheritance of specific genetic traits allowing a species to live in a particular environment. - Population-level phenomenon.  Evolution

Figure 03.04

Figure 03.01

10 Natural Selection 6. Natural Selection - Describes process where better competitors survive and reproduce more successfully.  Small, spontaneous, random mutations occur in every population creating genetic diversity.  Limited resources or environmental conditions may exert 7. selective pressure on a population.

11 Factors Exerting Selective Pressure 8. Physiological stress due to inappropriate levels of a critical environmental factor.  Moisture, Light, pH  (Perfect level=optimal range) 9. Predation 10. These selective pressures often lead to speciation.  Parasitism, Disease Competition

Speciation Given enough time, mutations may collectively allow a species to become better suited to new environmental conditions.  12. Divergent - Separation of one species into new species.  13. Convergent - Unrelated organisms evolve to look and act alike.

13 Galapagos Finches

14 Taxonomic Naming System Binomial - Based on Latin.  Kingdom  Phylum  Class  Order  Family  Genus  Species

15 Ecological Niche 14. Habitat - Set of environmental conditions in which a particular organism lives.  15. Ecological Niche - Description of role played by a species in a biological community. - Total set of environmental factors that determines species distribution.  Generalists – 16. Broad niche  Specialists – 17. Narrow niche

Resource Partitioning

17 Ecological Niche Cont’d Resource Partitioning - Alter behavior or physiology to minimize competition.  Allows several species to utilize different parts of the same resource.

18 Ecological Niche

19 Weedy Species 19. Opportunistic Species - Quickly appear when opportunities arise. Ex. Regular lawn mowing selects short flowers as tall flowers cant reproduce.  Many weeds. 20. Pioneer Species - Can quickly colonize open, disturbed, or bare ground.

20 SPECIES INTERACTION 21. Predation  Any organism that feeds directly on another living organism is termed a predator. (actually includes herbivores eating plants)  Predation Influences: - All stages of predator and prey life cycles. - Specialized food-obtaining mechanisms. - Specific predator-prey adaptations.  Predation can exert selective pressures Coevolution

Figure 03.10

Examples of specialized food-obtaining mechanisms: fast, big brained, packs, can ambush, camo, have pursuit skills, and intelligence. Ex. Of predator-prey adaptations: camo, warning coloration, plants with spines, toxins, chemicals, & wax. 22

23 Competition 23. Intraspecific - Competition among members of the same species.  Dispersal  Territoriality  Resource Partitioning having different niches for juveniles, reducing competition 24. Interspecific - Competition between members of different species.  Territoriality Defending resource-rich area, primarily against members of own species.  Resource Allocation and Spacing

Figure 03.11

Competitive Exclusion graph: 25

Figure 03.12

Epiphytes Ferns and bromeliads: In commensalistic realtionship with the tree 27

28 Symbiosis 25. Symbiosis - Intimate living together of members of two or more species.  26. Commensalism - One member benefits while other is neither benefited nor harmed. Cattle & Cattle Egrets or trees & epiphytes or ferns & bromeliads or hummingbirds & mites  27. Mutualism - Both members benefit. - Lichens (Fungus and cyanobacterium) - (Lichens also called a pioneer species) - Ex. Of mutualism: Mycorrhizal fungi helps plants with nutrient absorption

Figure 03.13

 28. Parasitism - One member benefits at the expense of other.  Humans and Tapeworms  Pathogen: disease causer  Tick & dog 30

Figure 03.14

32 Defensive Mechanisms  29. Batesian Mimicry - Harmless species evolve characteristics that mimic unpalatable or poisonous species.  30. Mullerian Mimicry - Two unpalatable or dangerous species evolve to look alike.  Ex. Wasp & beetle

Figure 03.15

34 Keystone Species 31. Keystone Species - A species or group of species whose impact on its community or ecosystem is much larger and more influential than would be expected from mere abundance. NOT usually most abundant.  Often, many species are intricately interconnected so that it is difficult to tell which is the essential component. - Top Predators - Multiple Key Players

Giant Kelp forests off Pacific coast in CA

36 POPULATION DYNAMICS 32. Population Growth  33. Exponential Growth - Growth as a percentage of the whole. - dN/dt=rN - Where dt=time & dN= (b-d)+(i-e) & r=growth rate  34. Biotic Potential - Potential of a population to grow in the absence of expansion limitations. Max # that the organism can produce.

Figure 03.17

38 Boom and Bust Cycles Exponential growth is graphed as a J curve.  35. Carrying Capacity - Number of individuals that can be indefinitely supported in a given area. - Overshoot - When a population surpasses the carrying capacity of its environment.  Dieback  Oscillations

39 Population Oscillations

40 Growth to a Stable Population 36. Logistic Growth - Growth slows as the population approaches carrying capacity.

41 Limiting Factors: usually many, but sometimes a specific critical factor. 37. Environmental Resistance  38. Density-Dependent Factors - Mortality rates increase as the density of the population increases. - Disease, Stress, Predation  39. Density-Independent Factors - Effect on mortality rate is independent of population density. - Abiotic conditions. Drought, fire, habitat destruction (often human caused)

Figure 03.19

(r) Strategies Short life Rapid growth Early maturity Many small offspring Little parental care Little investment in individual offspring Adapted to unstable environment Pioneers, colonizers Niche generalists Prey Regulated mainly by extrinsic factors Low trophic level

(K) Strategies Long life Slower growth Late maturity Fewer large offspring High parental care and protection High investment in individual offspring Adapted to stable environment Later stages of succession Niche specialists Predators Regulated mainly by intrinsic factors High trophic level

45 COMMUNITY PROPERTIES 42. Primary Productivity - Rate of biomass production. Used as an indication of the rate of solar energy conversion to chemical energy.  43. Net Primary Productivity - Energy (amount of biomass) left after respiration.

Figure 03.21

47 Abundance and Diversity 44. Abundance -Total number of organisms in a community. 45. Diversity - Number of different species, ecological niches, or genetic variation.  Abundance of a particular species often inversely related to community diversity.  As a general rule, diversity decreases and abundance within species increases when moving from the equator to the poles.

48 Complexity 46. Complexity - Number of species at each trophic level, and the number of trophic levels, in a community.  Diverse community may not be complex if all species are clustered in only a few trophic levels.  Highly interconnected community may have many trophic levels, some of which can be compartmentalized.  Decreased complexity means decreased diversity.

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50 Resilience and Stability Constancy 47. (Lack of fluctuation) Inertia (Resistance to pertubation) Renewal 48. (Ability to repair damage)  MacArthur (1955) proposed complex, interconnected communities would be more stable and resilient in the face of disturbance. - Controversial

51 Community Structure 49. Randomly Arranged  Individuals live wherever resources are available. 50. Clumped  Individuals cluster together for protection, assistance, or resource access. Regularly Arranged or ordered

52 Community Structure

Figure 03.24

54 Edges and Boundaries 51. Ecotones - Boundaries between adjacent communities. 52. Edge Effects - Important aspect of community structure is the boundary between one habitat and others.  May produce differently-shaped habitat patches.

55 Preserve Shape

56 COMMUNITIES IN TRANSITION Ecological Succession  53. Primary Succession - A community begins to develop on a site previously unoccupied by living organisms. - Pioneer Species  54. Secondary Succession - An existing community is disrupted and a new one subsequently develops at the site.  Ex. An abandoned field or after a clear-cut - Ecological Development

57 Primary Succession

58 Ecological Succession 55. Climax Community - Community that develops and seemingly resists further change.  Clements 56. Individualistic Community - Species become established according to their ability to colonize and reproduce in a given area.  Gleason

Figure 03.28

Figure 03.29

61 Introduced Species If introduced species prey upon, or compete more successfully than, native populations, the nature of the community may be altered.  Human history littered with examples of introducing exotic species to solve problems caused by previous introductions. - Mongoose and Rats in Caribbean

Figure 03.30

Gross Primary Productivity Defined as the total amount of CO 2 that is fixed by the plant in photosynthesis. Ocean areas with greatest GPP 1. Shallow waters near the continents 2. Along coral reefs (where enough light, heat & nutrients are available) 3. Current upwellings that move N & P up from the sea floor.

58. Lowest GPP 1. Deserts & other arid regions 2. Open ocean due to a lack of nutrients 64

Respiration, R Respiration, R, is the amount of CO 2 that is lost from an organism or system from metabolic activity. Respiration can be further divided into components that reflect the source of the CO 2 65

59. NPP Net Primary Production, NPP, is the net amount of primary production after the costs of plant respiration are included. Therefore, NPP = GPP - R Net primary productivity: the units of energy or biomass available to consumers Ex. Kcal/m 2 /yr or g/m 2 /yr 66

Greatest NPP 1. Estuaries 2. wetlands 3. tropical rainforest (also most diverse, as they are stable & have many niches) Humans increase productivity in agricultural lands by selecting certain crops, irrigation, and using fertilizers. 67

Lowest NPP 1. Open ocean 2. tundra 3. desert 68

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