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Population Ecology

Population Ecology. Population Ecology. Dynamics of species’ populations Interaction of populations with environment. Groups. Most species live in groups. Population Viability. Probability that a species will persist. Population Viability. Increased (+). Decreased (-).

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Population Ecology

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  1. Population Ecology

  2. Population Ecology • Dynamics of species’ populations • Interaction of populations with environment

  3. Groups • Most species live in groups

  4. Population Viability • Probability that a species will persist

  5. Population Viability Increased (+) Decreased (-) Unfavorable environment Many competitors Unsuitable defenses Cannot migrate Not resistant Insufficient Specialized niche Unsatisfactory habitat • Favorable environment(light, temp, nutrients) • Few competitors • Suitable defense mechanisms • Able to migrate • Resistance to disease • Sufficient food • Generalized niche • Satisfactory habitat

  6. Carrying Capacity (K) • Number of organisms that an environment can support

  7. Carrying Capacity (K) • Below K, population increases • Above K, population decreases

  8. Limiting Factors • Keep populations in balance with environment • Density dependent • Density independent

  9. Biotic Potential • Max rate at which a population can grow • When? • Influences:

  10. Growth Patterns • Exponential Growth • Logistic Growth http://www.allamericanpatriots.com/photos/salmonella-bacteria

  11. Growth Patterns

  12. Reproductive Strategies • Adaptations • Maximize growth rate when lacking limiting factors • r-strategists • r = growth rate (births-deaths) • Maintain population size near K • K-strategists • K = carrying capacity

  13. Reproductive Strategies r-strategists K-strategies Mature slowly Long lived Tend to be predators Few offspring High parental care Most endangered species are K-species • Mature rapidly • Short lived • Tend to be prey • Many offspring (overproduction) • Low parental care • most pest species are r-selected

  14. Reproductive Strategies r-strategists K-strategies Stabilized population Larger Limited by dependent factors • Wide fluctuations in population • Usually small • Limited by independent factors

  15. Reproductive Strategies • K or r?

  16. Survivorship Curves • At what point during an organism’s life does it die? • Curves show age distribution characteristics, reproductive strategies, and life history • Curves represent balance between resource limitations and competition

  17. Survivorship Curves

  18. Survivorship Curves

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