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

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Presentation on theme: "Population Ecology. Dynamics of species’ populations Interaction of populations with environment Population Ecology."— Presentation transcript:

1 Population Ecology

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

3 Most species live in groups Groups

4 Probability that a species will persist Population Viability

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

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

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

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

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

10 Exponential Growth Logistic Growth Growth Patterns

11 Growth Patterns

12 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 Reproductive Strategies

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

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

15 K or r? Reproductive Strategies

16 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 Survivorship Curves

17

18 TypeDescription I. Late LossReproduction occurs fairly early in life. Low mortality at birth. High probability of surviving until old age II. Constant LossAll ages have fairly uniform death rate. Death usually due to predation III. Early LossLarge numbers of offspring. High death rate for young, declines with age. Survivorship Curves


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