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Population Ecology ( Ch.5)

organism. population. community. ecosystem. biosphere. Population Ecology ( Ch.5). Factors that affect Population Size. Density Independant - Abiotic factors Amount ofsunlight & temperature precipitation / water soil / nutrients Density Dependant -Biotic factors

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Population Ecology ( Ch.5)

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  1. organism population community ecosystem biosphere Population Ecology (Ch.5)

  2. Factors that affect Population Size • Density Independant - Abioticfactors • Amount ofsunlight & temperature • precipitation / water • soil / nutrients • Density Dependant -Biotic factors • other living organisms • prey (food) • competitors • predators, parasites, disease

  3. Devil’s hole pupfish Iiwi Hawaiian bird Iriomote cat Socorro isopod New Guinea tree kangaroo Catalina Island mahogany tree Northern white rhinoceros At risk populations • Endangered species • limitations to range / habitat, over hunting, fishing • Loss of habitat (clear cutting, development, farming) • Changes in environment, competition. Introduced species that take over!

  4. marking territory = competition

  5. Population Spacing • Dispersal patterns of a population Provides insight into the environmental associations & social interactions of individuals in population clumped random uniform

  6. Births and immigration add individuals to a population. Immigration Births PopuIationsize Emigration Deaths Deaths and emigration remove individuals from a population. Population Size • Changes to population size • (4 factors)- • adding & removing individuals from a population • 1)Birth (B) • 2)Death (D) • 3)Immigration (I) • 4)Emigration (E)

  7. Age structure • Relative number of individuals of each age What do these data imply about population growth in these countries?

  8. 1000 Human (type I) Hydra (type II) 100 Survival per thousand Oyster (type III) 10 1 0 25 50 75 100 Percent of maximum life span Survivorship curves What do these graphs tell about survival & strategy of a species? • Generalized strategies I. High death rate in post-reproductive years II. Constant mortality rate throughout life span III. Very high early mortality but the few survivors then live long (stay reproductive)

  9. Reproductive strategies • K-selected • late reproduction • few offspring • invest a lot in raising offspring • Primates (us) • Big mammals r-selected • early reproduction • many offspring • little parental care • insects • many plants K-selected r-selected

  10. Exponential growth rate (J) curve - • Characteristic of populations without limiting factors (wide open resources) • introduced to a new environment or rebounding from a catastrophe Whooping crane coming back from near extinction African elephant protected from hunting

  11. gypsy moth Introduced (Invasive) species • Non-native species • transplanted populations may grow exponentially in new area • May out-compete native species • lack of predators, parasites, competitors • reduce diversity • examples • African honeybee • gypsy moth • zebra mussel • purple loosestrife kudzu

  12. ~2 months ecological & economic damage Zebra mussel, Cane Toad http://www.youtube.com/watch?v=gX1FLXEo96g • reduces diversity • loss of food & nesting sites for animals • economic damage

  13. 1968 1978 Purple loosestrife • reduces diversity • loss of food & nesting sites for animals

  14. The Snakehead • Great Snakehead Problems Snakeheads eat game fish and have no predators so they can overcrowd a body of water and harm native species. They are adapted to survive in water with little oxygen and can even crawl across land for short distances on their fins, taking in oxygen from a special bronchial adaptation. They will not attack people but may injure anyone stepping on them. http://www.youtube.com/watch?v=nmU7etSYYqI

  15. Logistic rate of growth Of course not! • Can populations continue to grow exponentially? no natural controls K =carryingcapacity effect of natural controls

  16. Significant advances in medicine through science and technology Industrial Revolution Human population growth adding 82 million/year ~ 200,000 per day! What factors have contributed to this exponential growth pattern? 20056 billion Is the human population reachingcarrying capacity? Bubonic plague "Black Death" 1650500 million

  17. Assuming these age structure diagrams describe human populations, in which population is unemployment likely to be most severe in the future? • I • II • III • No differences in the magnitude of future unemployment would be expected among these populations.

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