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Course objectives

This course delves into the interrelationship between living and non-living environments, focusing on ecological principles, heredity, and the functioning of the human body. Students will explore the dynamics of various ecological levels, from organismal to landscape ecology, and gain knowledge about population characteristics, distribution patterns, and community interactions. Key topics include density and dispersion, population growth models, and survivorship curves, all aimed at providing a comprehensive understanding of ecological systems and informing environmental policy and education.

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Course objectives

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  1. Course objectives • Understand how living and non-living environments are interrelated • Understand how cells function • Understand principles of heredity • Understand how the human body functions

  2. Ecology Ch 46

  3. Ecology • Abiotic & biotic factors • History ie scale • Interactions

  4. Ecology and Environment • Understanding • Knowledge of impacts • Information for policy • Education

  5. Ecological Scale • Organismal ecology • Population ecology • Community ecology • Ecosystem ecology • Landscape ecology

  6. Organismal Ecology • Individual level interaction w/ environment • Morphology, Physiology, Behavior • Can influence geographic distribution

  7. Population Ecology • Group of organisms of one species in a given area • Interactions w/ abiotic & biotic • Evolutionary important unit

  8. Community Ecology • All species in a given area and their interactions w/ abiotic and biotic • Influences community structure • Ex. Predator prey interactions, competition, niche partitioning

  9. Ecosystem Ecology • Interaction among all communities and the abiotic and biotic factors • Flow/ cycles of nutrients & energy

  10. Landscape Ecology • Largest scope • Interactions amongst ecosystems • Atmosphere to deep ocean bottom • Biosphere

  11. Population Ecology • Group of organisms of one species in a given area • Interactions w/ abiotic & biotic • Evolutionary important unit

  12. Population • Group of individuals of a single species that simultaneously occupy the same general area • Characterized by density and spacing

  13. Population Characteristics • Face similar environmental conditions • Exhibit variation, unit of evolution • Demography- Study of populations and how they change • Physical structure • Density • Dispersion • Population growth • Birth & death rates • Life Table • Age structure • Survivorship curve • Population size regulation • Density dependent/independent factors • Growth Models • Life history patterns

  14. Density & Dispersion • Density • Number individuals per unit area/volume • Dispersion • Pattern of spacing among individuals w/in the geographic boundaries of the population • Used to understand the physical structure of a population • Patterns vary according to scale and animals interaction with environment

  15. Spatial Distribution

  16. Impacts on Density & Dispersion • Ecological needs • Feeding strategy • Social structure (Intraspecific interactions) • Resource distribution • Limiting resource drives distribution patterns

  17. Patterns of Dispersion • Clumped • Uniform • Random

  18. Most common Clumping around patchy resource Nutrients Sunlight Mates Protection Clumped

  19. Evenly spaced Typically due to competition for resource Uniform

  20. Creosote Bush

  21. Unpredictable spacing Absence of strong attractants/ repulsions Not common Random

  22. Impacts • Feeding strategy • Reproduction • Social structure

  23. Population Growth • Biotic potential • Highest rate of natural population size increase • Assumes no limiting factors • Usual number of offspring per reproduction • Reproduction table • Chances of survival to age of reproduction • Life Table • Survivorship curve • Frequency of reproduction • Reproduction table • Age of reproduction • Age structure

  24. Reproductive Table • Summary of reproductive rates in a population • Female biased

  25. Age Distribution of Populations Indicates Growth Potential

  26. Life Table • Track life expectancy • Info on survivorship • Study cohort • Individuals of same age from birth to death

  27. Survivorship Curve • Visual representation of life table data

  28. Survivorship Curve • 3 general survival patterns ie survival strategies • Type I • Low death rate early to middle life, incr death rate at old age. Ex humans • Few offspring produced with more care invested in each increases survivorship • Type II • Intermediate pattern- constant death rate over lifespan • Type III • High early death rate • Many offspring with little care investment

  29. Survivorship Curve

  30. Type I Death rate increases with age

  31. Type II Constant death rate

  32. Type III High initial death rate

  33. Population Growth • Rates & patterns of population growth • Study factors that influence patterns • Birth rate • Death rate • Immigration/ emmigration • 3 primary patterns of population growth • No growth • Unregulated/ unchecked growth • Regulated growth

  34. Population Growth Models • Models used to characterize growth patterns • Zero population Growth • Exponential model • Logistic growth model

  35. Zero Growth Model • Net birth rates & death rates are equal • Population exhibits no net growth • Greatly impacted by disturbance

  36. Exponential Growth Model • No regulation in growth patterns • Net increase in population growth • Occurs in conditions when • Resources are abundant • Predators/ limiting factors are absent • Characterized by J shaped curve • Examples • Reintroduced populations • Protected species • Exploitation of new environment • Non-native species

  37. Exponential Growth Model

  38. Logistic Growth Model • “Realistic” growth model • Takes into account limitations in resources • Food, predator interactions, competition, etc. • Carrying capacity • Maximum population size the environment can support • Dynamic according to abiotic & biotic parameters • Characterized by S shaped curve

  39. Logistical Growth Model

  40. Logistical Growth Model

  41. Regulation of Population Growth • Factors (abiotic or biotic) that influence and/or limit patterns of population growth • Why do populations stop growing? • Density independent • Density dependent • Negative feedback • Population cycles

  42. Density Independent • A population-limiting factor whose effects are independent of population density • No negative feedback to control growth • Environmental conditions

  43. Population Cycles

  44. Density Dependent • A population-limiting factor whose effects depend on population density • Competition for resources • Territoriality • Health • Predation Results in negative feedback systems

  45. Competition for Resources • Increase intraspecific competition • Less resources allocated per individual • Results in decreased reproductive output

  46. Territoriality • Territory (space) and it’s resources are a limiting factor

  47. Health • As population size increases interaction increases • Transmission of disease & wastes increases

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