Population Biology: Threats and Management
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Questions and Answers

What is the term for random fluctuations in population size and environmental conditions?

  • Effective population size
  • Genetic drift
  • Environmental stochasticity (correct)
  • Heterozygosity
  • What is the average number of alleles per locus in African lions?

  • 7.0%
  • 1.0
  • 1.27 (correct)
  • 7.1%
  • What is the term for the portion of the population that passes its genes onto the next generation?

  • Mutation rate
  • Genetic drift
  • Effective population size (correct)
  • Observed heterozygosity
  • What is the term for individuals that carry different alleles for a particular trait?

    <p>Heterozygotes</p> Signup and view all the answers

    What is the consequence of genetic drift in small populations?

    <p>Reduction in genetic diversity</p> Signup and view all the answers

    What is the term for the proportion of heterozygotes that would exist if random breeding takes place in a population?

    <p>Expected heterozygosity</p> Signup and view all the answers

    What does small population size lead to at a faster rate than large populations?

    <p>Genetic drift</p> Signup and view all the answers

    Which process can override the effects of selection and mutation in small populations?

    <p>Genetic drift</p> Signup and view all the answers

    What is the primary process affecting genetic variation in small populations?

    <p>Genetic drift</p> Signup and view all the answers

    What is the term for the variation of alleles and genotypes present in a population?

    <p>Genetic diversity</p> Signup and view all the answers

    What does effective population size (Ne) represent?

    <p>The portion of the population that passes its genes onto the next generation.</p> Signup and view all the answers

    What can lead to an increase in extinction risk?

    <p>The reduction in genetic diversity</p> Signup and view all the answers

    Which factor causes random unpredictable variation in environmental factors such as temperature and rainfall?

    <p>Environmental stochasticity</p> Signup and view all the answers

    What is the term for random unpredictable variation in sex ratios, and birth and death rates?

    <p>Demographic stochasticity</p> Signup and view all the answers

    Which term refers to extreme environmental events such as disease epidemics or hurricanes?

    <p>Catastrophes</p> Signup and view all the answers

    What do small populations tend to be more inbred, lose genetic diversity more rapidly, and have a reduced ability to adapt to environmental change than large populations?

    <p>Genetic deterioration</p> Signup and view all the answers

    What is the term for the numbers game involving population growth rates, mortality, reproductive rates and life tables?

    <p>Demography</p> Signup and view all the answers

    What does an age pyramid graphically demonstrate?

    <p>The sex and age structure of a population</p> Signup and view all the answers

    Which factor has a larger impact in smaller populations?

    <p>Demographic stochasticity</p> Signup and view all the answers

    'Scimitar-horned oryx EEP' is associated with which aspect of population biology?

    <p>Demographic stability</p> Signup and view all the answers

    Which process causes random changes in allele frequencies within a population and affects larger populations less than smaller ones?

    <p>Genetic Drift</p> Signup and view all the answers

    What causes substantial population contractions and can be caused by catastrophic events, habitat loss, fragmentation, or intentional actions like captive release and reintroductions?

    <p>Population Bottlenecks</p> Signup and view all the answers

    Which mating practice increases homozygosity and decreases heterozygosity?

    <p>Inbreeding</p> Signup and view all the answers

    What measures the relatedness of an individual's parents and higher values indicate greater inbreeding?

    <p>Inbreeding coefficient (F)</p> Signup and view all the answers

    What negative effects result from crosses of genetically differentiated populations, like hybridization in Ibex populations which led to offspring maladaptation and population extinction?

    <p>Outbreeding depression</p> Signup and view all the answers

    What results in a number of small populations, increasing the risk of extinction due to inbreeding, demographic fluctuations, and the extinction vortex?

    <p>Population structure and fragmentation</p> Signup and view all the answers

    What feedback loop causes population decline and extinction as a result of human impacts, inbreeding, and demographic fluctuation?

    <p>'Extinction vortex'</p> Signup and view all the answers

    What makes small populations more susceptible to extinction than larger ones due to demographic, genetic, and ecological reasons?

    <p>'Population structure and fragmentation'</p> Signup and view all the answers

    Which factor can push populations towards extinction in the extinction vortex?

    <p>'Overhunting'</p> Signup and view all the answers

    Study Notes

    • Genetic Drift: process causing random changes in allele frequencies within a population, affects larger populations less than smaller ones
    • Population Bottlenecks: occurrences of substantial population contractions, can be caused by catastrophic events, habitat loss, fragmentation, or intentional actions like captive release and reintroductions
    • Populations that have experienced bottlenecks have lower genetic diversity than those that haven't
    • Inbreeding: mating between relatives, increases homozygosity and decreases heterozygosity
    • Inbreeding depression: negative effects on offspring, including increased juvenile mortality, reduced longevity, and reduced reproductive fitness
    • Inbreeding depression can cause population declines and extinctions in various species, such as bighorn sheep, Florida panthers, and greater prairie chickens
    • Inbreeding coefficient (F): measures relatedness of an individual's parents, higher F values indicate greater inbreeding
    • Outbreeding depression: negative effects resulting from crosses of genetically differentiated populations, like hybridization in Ibex populations which led to offspring maladaptation and population extinction.
    • Population structure and fragmentation: fragmentation results in a number of small populations, increasing risk of extinction due to inbreeding, demographic fluctuations, and the extinction vortex.
    • Extinction vortex: a feedback loop of human impacts, inbreeding, and demographic fluctuation that causes population decline and extinction
    • Small populations are more susceptible to extinction than larger ones, due to demographic, genetic, and ecological reasons.
    • Population fragmentation increases the number of small populations, making them more vulnerable to extinction.
    • Habitat loss, epidemic diseases, overhunting, invasive species, demographic stochasticity, and catastrophic events are factors that can push populations towards extinction in the extinction vortex.
    • Genetic, demographic, and environmental factors can make it difficult to identify the immediate cause of extinction.

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    Description

    Learn about the challenges faced by small populations and the genetic factors that cause population extinction. Explore management interventions to counter these threats and contribute to the conservation of species.

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