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Limitations in Environmental Science
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Limitations in Environmental Science

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  1. Limitations in Environmental Science Cannot prove or disprove Human-generated bias Statistics and sampling Confounding factors Testable hypotheses ***These are the same limitations as other sciences

  2. Matter Anything that has mass and takes up space Cannot be created or destroyed (law of conservation of matter) Can change form

  3. Energy Capacity to do work or transfer heat Potential energy – stored energy Kinetic energy – energy being use/released Governed by two laws

  4. First Law of Thermodynamics Energy cannot be created or destroyed Energy can only change form (transformation)

  5. Second Law of Thermodynamics With transformation, some energy converted to heat (lower quality) Entropy Energy Efficiency 16% energy produced in US performs useful work (41% lost by entropy)

  6. System System – set of components that function together Systems respond to change Positive feedback loops – changes in same direction Negative feedback loops – changes in opposite direction

  7. Prey Numbers Increase Predator Numbers Decrease Predator Numbers Increase Prey Numbers Decrease

  8. Thresholds/Tipping Points Threshold – system pushed to a new functional state Can be irreversible

  9. What Do We Study? ** Biome Level

  10. Population Level Distribution (limiting factors, tolerance, fundamental niche) Density

  11. dN/dt = rN dN/dt = rN((K-N)/K)

  12. Population Level Population Growth – positive or negative changes can help in understanding nature of response Challenge is recognizing multiple factors might be involved Example – Science Focus p. 110

  13. Why is Sea Otter Population Increase Slow? Slow reproduction Increase # orcas Cat parasites via kitty litter Toxic algal blooms (urea from fertilizer) PCBs & other pollutants (otters as biomagnifiers)

  14. Recognizing Strategies of a Population:r-selected and K-selected species

  15. Populations fluctuate around K or do not reach it? Why?

  16. Community Level Role of Interactions Competition Predation Parasitism Mutualism Commensalism Have proximate (ecological) and ultimate (evolutionary) impacts

  17. Competition – Evolutionary Influence Prevent species from reaching carrying capacity Change niche (realized niche) - barnacles Competitive exclusion

  18. Competition – Evolutionary Influence Resource Partitioning

  19. Competition – Evolutionary Influence Character Displacement

  20. Predation Population regulation “Coevolutionary dance”

  21. Evolution Avoidance strategies Enhancement strategies The arms race (or is it?)