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Questions and Answers
What does the rate of growth (r) equal?
What does the rate of growth (r) equal?
- Births + Emigration – Deaths + Immigration
- Births – Deaths + Immigration + Emigration
- Births + Deaths + Immigration – Emigration
- Births + Immigration – Deaths – Emigration (correct)
Which of the following statements about mortality is true?
Which of the following statements about mortality is true?
- Mortality is connected only to the birth rate.
- Mortality can be influenced by an organism's life span. (correct)
- Mortality rate is unaffected by environmental factors.
- All organisms have the same mortality rate.
Which pair of factors lead to population growth?
Which pair of factors lead to population growth?
- Deaths and Emigration
- Births and Immigration (correct)
- Immigration and Deaths
- Births and Emigration
What pattern do many larger mammals follow regarding offspring survival?
What pattern do many larger mammals follow regarding offspring survival?
Which of the following contributes negatively to the rate of growth?
Which of the following contributes negatively to the rate of growth?
What best describes organisms that have equal likelihood of dying at any age after infancy?
What best describes organisms that have equal likelihood of dying at any age after infancy?
What happens to birth rates when there are food shortages?
What happens to birth rates when there are food shortages?
What is the primary effect of high population density on desert locusts?
What is the primary effect of high population density on desert locusts?
What allows the desert locust to go from solitary to swarming behavior?
What allows the desert locust to go from solitary to swarming behavior?
Which regions are notably affected by swarms of desert locusts?
Which regions are notably affected by swarms of desert locusts?
How much food can a single swarm of locusts consume in a day?
How much food can a single swarm of locusts consume in a day?
What historical significance do records of locust plagues hold?
What historical significance do records of locust plagues hold?
What is the typical life cycle behavior of desert locusts during calm periods?
What is the typical life cycle behavior of desert locusts during calm periods?
What is a risk posed by the biotic potential for reproduction in desert locusts?
What is a risk posed by the biotic potential for reproduction in desert locusts?
What is the average distance that a locust swarm can travel in a single day?
What is the average distance that a locust swarm can travel in a single day?
What happens to locust numbers under typical desert conditions?
What happens to locust numbers under typical desert conditions?
What term describes the curve that illustrates mortality rates being consistent with age?
What term describes the curve that illustrates mortality rates being consistent with age?
Which type of factors are typically affected by the population size?
Which type of factors are typically affected by the population size?
What is the effect of abiotic factors on populations?
What is the effect of abiotic factors on populations?
What ecological principle explains the oscillation of predator and prey populations?
What ecological principle explains the oscillation of predator and prey populations?
What is a primary consequence of intraspecific competition?
What is a primary consequence of intraspecific competition?
Which type of factors could lead to high mortality rates during a population overshoot?
Which type of factors could lead to high mortality rates during a population overshoot?
Which of the following best illustrates abiotic factors affecting populations?
Which of the following best illustrates abiotic factors affecting populations?
How do occasional abiotic disturbances like fire affect ecosystems?
How do occasional abiotic disturbances like fire affect ecosystems?
What might cause stress-related diseases among organisms in high-density populations?
What might cause stress-related diseases among organisms in high-density populations?
What is the relationship between seed or egg production and survival rates in many species?
What is the relationship between seed or egg production and survival rates in many species?
Which factor is NOT a biotic factor affecting populations?
Which factor is NOT a biotic factor affecting populations?
How do successful individuals in a species typically contribute to population sustainability?
How do successful individuals in a species typically contribute to population sustainability?
What is a common outcome of density-independent factors impacting a population?
What is a common outcome of density-independent factors impacting a population?
What is the potential impact of a hurricane on a population?
What is the potential impact of a hurricane on a population?
Flashcards
What factors influence population growth?
What factors influence population growth?
The rate at which a population grows is determined by the balance of births, immigration, deaths, and emigration.
What is the difference between immigration and emigration?
What is the difference between immigration and emigration?
Immigration is the movement of individuals into a population, while emigration is the movement of individuals out of a population.
What is mortality?
What is mortality?
The portion of a population that dies in a given period.
What factors influence mortality?
What factors influence mortality?
Environmental factors, such as disease or limited resources, and an organism's natural lifespan contribute to mortality.
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What is a survivorship curve?
What is a survivorship curve?
The pattern of survival and death over an organism's lifespan.
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What is Type I survivorship?
What is Type I survivorship?
Organisms that invest heavily in a few offspring, with high juvenile and adult survival.
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What is Type II survivorship?
What is Type II survivorship?
Organisms with an equal chance of dying at any age after infancy.
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What is Type III survivorship?
What is Type III survivorship?
Organisms with high mortality rates during early life.
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Density-dependent transformations
Density-dependent transformations
The change in an organism's behavior or appearance due to a change in population density.
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Swarm
Swarm
A large group of insects that migrate together, typically locusts.
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Biotic potential
Biotic potential
The ability of an organism to reproduce and increase in population size.
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Bust
Bust
The decline in a population after a period of rapid growth.
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Boom
Boom
The rapid increase in a population.
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Intraspecific interactions
Intraspecific interactions
The interaction between members of the same species.
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Migration
Migration
The process of moving from one place to another, often in large groups.
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Environmental changes
Environmental changes
The factors that affect the distribution and abundance of organisms in an environment.
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Stress
Stress
Factors that trigger a response in an organism, especially stress.
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Population density
Population density
The number of individuals present in a given area.
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Type I Survivorship Curve
Type I Survivorship Curve
A straight line on a graph that shows a constant mortality rate with age.
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Intrinsic Factors
Intrinsic Factors
Factors that operate within individual organisms or between organisms of the same species, influencing population dynamics.
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Extrinsic Factors
Extrinsic Factors
Factors that originate from outside the population, affecting population dynamics.
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Biotic Factors
Biotic Factors
Factors that are caused by living organisms, influencing population dynamics.
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Abiotic Factors
Abiotic Factors
Factors that are caused by non-living components of the environment, influencing population dynamics.
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Occasional Events or Disturbances
Occasional Events or Disturbances
Events or disturbances that have a large impact on populations and can be either beneficial or harmful.
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Density-Dependent Factor
Density-Dependent Factor
A factor influencing population dynamics that is affected by the size of the population.
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Density-Independent Factor
Density-Independent Factor
A factor influencing population dynamics that is unaffected by the size of the population.
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Predation
Predation
A type of interaction between species where one species benefits by consuming another.
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Interspecific Competition
Interspecific Competition
An interaction between species where both species are harmed due to competing for the same resources.
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Intraspecific Competition
Intraspecific Competition
A type of interaction between individuals of the same species where they compete for resources.
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Carrying Capacity
Carrying Capacity
The maximum population size that an environment can sustainably support.
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Establishing Territories
Establishing Territories
The process of establishing a defined area within an environment by an individual or group to control access to resources.
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Stress Shock
Stress Shock
Stressful conditions caused by high population densities and competition.
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Lotka-Volterra Model
Lotka-Volterra Model
A model that describes the cyclical relationship between predator and prey populations.
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Population Growth Factors
- Rate of growth is calculated as (Births + Immigration) – (Deaths + Emigration)
- This model applies to both human and animal populations.
- Birth rates vary between species and can decline due to factors like food shortages or stress.
- Emigration is the departure of individuals from a population.
- Deaths, or mortality, have patterns influenced by environmental factors and an organism's natural lifespan.
- Life spans greatly vary, from minutes for microorganisms to thousands of years for bristlecone pines.
Survivorship Patterns
- Different organisms exhibit different survivorship curves.
- Some, like whales and elephants, have high juvenile survival and low adult mortality.
- Others, like seagulls and mice, have roughly constant mortality rates across their lifespan.
- Organisms producing numerous offspring, like fish and trees, often have high initial mortality but high survival past reproduction.
Factors Affecting Population Dynamics
- Factors can be intrinsic (within the population) or extrinsic (outside the population), biotic (living) or abiotic (non-living).
- Biotic factors include predators, competitors, prey, and their abundance.
- Abiotic factors are environmental conditions like climate, soil type, water, and occasional events like fires, floods, and droughts. These can have positive or negative impacts.
- Some factors are density-dependent (e.g., predation, competition, spread of disease) affecting populations based on their size.
- Other factors are density-independent (e.g., fires, droughts), affecting populations regardless of their size.
Population Interactions
- Predation can benefit a population by keeping its numbers in check, eliminating weak members. Predation–prey populations may oscillate.
- Intraspecific competition (within a species) drives competition for resources like food, mates, and territory.
- Territories regulate access to resources and limit competition within a species.
- Stress and crowding can negatively impact reproduction and increase mortality in dense populations.
Case Study: Desert Locust
- Desert locusts usually live solitary lives as grasshoppers.
- During periods of high rainfall and vegetation growth, locust populations surge, leading to density-dependent changes.
- Locusts form enormous swarms, migrate, and cause devastating crop damage.
- This cyclical boom-and-bust population dynamics can affect agricultural livelihoods for substantial portions of the global population.
- Actions by the Food and Agriculture Organization (FAO) have been taken in recent years to mitigate the impact of these swarms on various regions.
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