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Ecology of Populations

Ecology of Populations

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Ecology of Populations

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  1. Ecology of Populations Day #1:Introduction to Ecology

  2. Modern Biology Pages 359-360 What is the common theme for ecology? • “Interconnectedness” • Nothing exists by itself. • Interdependence. • All living organisms interact with; • Other organisms • Physical factors Key Words: Interdependence Niche Discussion

  3. Modern Biology Pages 361-362 What are the levels of organization found in the environment? • Biosphere is broadest of all. • All areas that support life. Key Words: Biosphere

  4. Modern Biology Pages 361-362 What are the levels of organization found in the environment? • Biomes are large areas of the Earth. • Common abiotic conditions in the area. Key Words: Biomes

  5. Modern Biology Pages 361-362 What are the levels of organization found in the environment? Ecosystems • All organisms and non-living environment in a given area. • Can be any size. Key Words: Ecosystems

  6. Modern Biology Pages 361-362 What are the levels of organization found in the environment? • Communities • All interacting organisms in an area. • Includes all species Key Words: Communities

  7. Modern Biology Pages 361-362 What are the levels of organization found in the environment? • Populations • All members of a species living in one area. Key Words: Population

  8. Modern Biology Pages 361-362 What are the levels of organization found in the environment? • Organism • Simplest level of organization in ecology. Key Words: Population

  9. Ecology of Populations Day #2:Ecology of Organisms

  10. Modern Biology Pages 363-365 How doorganisms interact with their environment? • Environmental factors; • Abiotic • Biotic • Interactions • Abiotic - abiotic • Abiotic - biotic • Biotic - biotic Key Words: Abiotic Biotic

  11. Modern Biology Pages 363-365 How doorganisms interact with their environment? • Abiotic factors always change, • Organisms must tolerate abiotic changes. • All organisms have a range of tolerance. Key Words: Tolerance Curve

  12. How doorganisms interact with their environment? Modern Biology Pages 363-365 • Tolerance curves shows how well a species tolerates abiotic changes.

  13. Modern Biology Pages 363-365 How doorganisms interact with their environment? • Acclimation • Not adaptation • How organisms react to changing abiotic conditions. • Ex: You and altitude Key Words: acclimation

  14. Modern Biology Pages 363-365 How doorganisms interact with their environment? • Conformers • Change with the environment. • Ex: Reptiles and body temperature. • Regulators • Maintain steady internal conditions. • Ex: Mammals Key Words: Conformer Regulators

  15. Modern Biology Pages 363-365 How doorganisms interact with their environment? • Escaping unfavorable conditions. • Migration • Hibernation • Dormancy Key Words: Dormancy Migration

  16. Ecology of Populations Day #3: Energy Transfer in Ecosystems

  17. Modern Biology Pages 366 Producers Are Essential To An Ecosystem • Energy flows through ecosystems. • Producers use energy to produce organic molecules. • Autotrophs • Use energy to produce carbohydrates. • Most use photosynthesis. • A few use chemosynthesis. Key Words: Producers Chemosynthesis Organic molecules

  18. Modern Biology Pages 366 What is Productivity? • Gross Primary productivity: • The rate at which producers capture energy. • Equal to all of the carbohydrates produced using photosynthesis. • Referred to as biomass. Key Words: biomass Gross Primary Productivity

  19. Modern Biology Pages 366 How is Productivity Measured? • Net Primary Productivity. • Measured as g/m2/year. • All organic material in an ecosystem is referred to as biomass (dry organic mass). • All stored energy in the ecosystem. • Rate at which biomass accumulates is NPP. Key Words: Net Primary Productivity Dry Organic Mass

  20. Modern Biology Pages 370 Consumers • Consumers are heterotrophs. • Obtain energy by consuming organic molecules. • Herbivores • Carnivore • Omnivore • Detritivore • Decomposers Key Words: Detritus Decomposers

  21. Modern Biology Pages 368-369 Energy Flow • Energy is transferred from organism to organism. • Trophic level is the feeding position in community. • Trophic levels: • 1st level = producers • 2nd level = herbivores • 3rd level = carnivore • 4th level = second carnivore Key Words: Trophic Level

  22. How is Energy Lost in Ecosystems? Modern Biology Pages 368-369

  23. Modern Biology Pages 368-369 Food Chains • A single pathway of energy through the ecosystem. • 5% of sun’s energy is preserved in the producers. • Approximately 10% of energy is preserved in each transfer.

  24. Modern Biology Pages 368-369 Food Webs • Several food chains interlinked. • Better shows energy flow in an ecosystem.

  25. Modern Biology Pages 368-369 Why Do We Find Just a Few Hawks In An Ecosystem?

  26. Modern Biology Pages 365 What is a specie’s niche? • The niche • The way of life. • The role in the environment • Includes all interactions in ecosystem. • Generalist Vs specialist What factors might be included in the artic wolf’s niche? Key Words: generalists specialists

  27. Modern Biology • Pages 371-372 Ecology of Organisms • Niche Differences • A species niche can change over time. • Generalists have very broad niches • Specialists have very specific niches. Why is it an advantage for the adult to feed on a different food source than the larva?

  28. Ecology of Populations Day #4:Measuring Populations

  29. Modern Biology Pages 381-384 Properties of Populations • Population size • Determined by: • actual count • sampling How many populations are shown here?

  30. Modern Biology Pages 366-369 Properties of Populations • Population Density • Expressed as: • # of Individuals/area. Key Words: Population density Population dispersion How would low density effect the condor population?

  31. Modern Biology Pages 366-369 Properties of Populations • Population dispersion • Clumped • Uniform • Random • Depends viewing scale in many cases. Could redwood trees demonstrate all three dispersions in different conditions?

  32. Modern Biology Pages 383-389 Population Dynamics • Dynamics means changing over time. • Change is due to: • Birth rate. • Death (mortality) rate. • Immigration • Emmigration What industry (business) pays close attention to this type of data?

  33. Modern Biology Pages 383-389 Population Dynamics • Survivorship curves • Type I • Type II • Type III Is survivorship type related to number of offspring produced?

  34. Modern Biology Pages 383-389 Population Dynamics • Age structure What information can you get from this chart?

  35. Modern Biology Pages 383-389 Population Growth • Population growth rate is size change over time. • Growth can be negative or positive. • Depends on any of four factors • Birth rate • death rate • Emmigration & immigation What two events might have led to the rapid increase in human populations?

  36. Modern Biology Pages 383-389 Exponential Growth Curve • Populations grow more rapidly as they increase in size. • “J” curve. • Demonstrates species biotic potential. • Unlimited resources. • Only occurs in rare cases. Can this growth curve occur for long periods of time? Why

  37. Modern Biology Pages 383-389 Logistic Growth Curve • Same as exponential for short time. • Growth slows and finally levels out. • Known as “S” curve. • Carrying capacity has been reached. What resource most likely causes this curve to flatten out?

  38. Comparison of Expoential and Logistic Growth Curves

  39. Ecology of Populations Day #5:Measuring Populations

  40. Modern Biology Pages 383-389 Factors that Limit Population Growth • Causes growth to be something less than biotic potential. • Referred to as limiting factors • Density dependent • Limits on resources. • Disease • Density independent • Weather • Fire Why so many rabbits in Australia?

  41. Modern Biology Pages 383-389 Factors that Limit Population Growth

  42. Modern Biology Pages 383-389 Dangers of Small Populations • Leads to: • Lack of genetic variation. • Inbreeding. • Lower birth rates. • Susceptible to extinction. Do zoos solve the problems of small populations?

  43. Modern Biology Pages 363-365 How is a fundamental niche different from a realized niche? • Fundamental niche • Full range of interactions in ecosystem. • All potential resources • Theoretical niche as if no other organisms present Why is the realized niche shown above smaller than the fundamental niche? Key Words: Fundamental niche Realized niche

  44. Modern Biology • Pages 371-372 Ecology of Organisms • Realized niche • All resources actually used. • Competition with other organisms limits fundamental niche. • Something less than the fundamental niche. Which species out competes the other species regarding niche?

  45. Why is there not a mixture of the two species in the overlap area?

  46. What strategies help the finches to survive?