Podcast
Questions and Answers
What is population size?
What is population size?
- The carrying capacity of an ecosystem
- The density of organisms per unit of space
- The number of individuals in a population (correct)
- The total biomass of all organisms in an area
Which of the following organisms is most likely to have the largest population size?
Which of the following organisms is most likely to have the largest population size?
- Tigers
- Moose
- Elephants
- Invertebrates (correct)
Which of the following best defines population density?
Which of the following best defines population density?
- The total number of organisms in a habitat
- The number of births minus deaths in a population
- The amount of biomass per unit of area
- The number of organisms per unit area or space (correct)
Which unit is most appropriate for measuring the density of soil invertebrates?
Which unit is most appropriate for measuring the density of soil invertebrates?
What is the main difference between maximum birthrate and ecological (realized) birthrate?
What is the main difference between maximum birthrate and ecological (realized) birthrate?
Which of the following is an example of emigration?
Which of the following is an example of emigration?
Which of the following is a 'density-dependent' factor affecting population size?
Which of the following is a 'density-dependent' factor affecting population size?
Which of the following population-dynamic processes directly increase population size?
Which of the following population-dynamic processes directly increase population size?
Which process is described as the death of individuals under actual environmental conditions?
Which process is described as the death of individuals under actual environmental conditions?
What effect does high population density have on the impact of certain factors?
What effect does high population density have on the impact of certain factors?
What is the definition of 'fertility' in population dynamics?
What is the definition of 'fertility' in population dynamics?
Which type of survival curve is characterized by high survival at young ages and decreased survival at older ages?
Which type of survival curve is characterized by high survival at young ages and decreased survival at older ages?
What is a likely consequence of excessively high population density?
What is a likely consequence of excessively high population density?
Which is an example of immigration within a population context?
Which is an example of immigration within a population context?
Which factor is most likely responsible for causing a decrease in population size?
Which factor is most likely responsible for causing a decrease in population size?
How do density-dependent factors influence population size?
How do density-dependent factors influence population size?
Which of the following processes is NOT typically associated with population dynamics?
Which of the following processes is NOT typically associated with population dynamics?
What is a characteristic feature of Type III survival curves?
What is a characteristic feature of Type III survival curves?
What effect does high fertility have on population dynamics?
What effect does high fertility have on population dynamics?
Flashcards
Population size
Population size
The total number of individuals of a particular species living in a specific area at a given time.
Population density
Population density
The number of individuals per unit area or volume.
Maximum birthrate
Maximum birthrate
The maximum possible birthrate under ideal conditions.
Ecological birthrate
Ecological birthrate
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Emigration
Emigration
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Density-dependent factors
Density-dependent factors
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Density-independent factors
Density-independent factors
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Immigration
Immigration
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Realized mortality
Realized mortality
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Mortality
Mortality
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Type I Survival Curve
Type I Survival Curve
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Population Dynamics
Population Dynamics
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Type II Survival Curve
Type II Survival Curve
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Type III Survival Curve
Type III Survival Curve
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Study Notes
Population Size & Dynamics
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Population size: The number of individuals in a population.
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Population density: The number of organisms per unit area or space. Suitable unit for soil invertebrates is individuals per 1 m².
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Maximum birthrate: The theoretical maximum number of offspring a population could produce under ideal conditions.
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Ecological (realized) birthrate: The actual number of offspring produced under prevailing environmental conditions. It's lower than the maximum birthrate.
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Emigration: Leaving a population and moving to a different region.
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Immigration: Moving into a population from another area.
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Density-dependent factors: Factors whose effect on a population increases as population density rises. Examples include food availability, competition, and spread of disease.
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Density-independent factors: Factors that affect population size regardless of density (like natural disasters). Examples include seasonal changes in temperature, hurricanes, earthquakes.
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Population-dynamic processes: Processes that directly alter population size; fertility, immigration, mortality, emigration.
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Mortality: The number of deaths in a population. "Realized mortality" refers to deaths under actual environmental conditions.
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Fertility: The ability of a population to increase its size through reproduction.
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Survival curves: Diagrams depicting patterns of survival across different ages. Type I curves show high survival at young ages and increased mortality at old ages (e.g., humans)
Factors Affecting Population Size
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Density-dependent factors: Intensify their effect as population density increases, e.g., competition for resources.
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Density-independent factors: Impact populations regardless of density, e.g., natural disasters.
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High population density: Can lead to increased competition, resulting in reduced growth and increased mortality among members of the population. Animals may be physically weaker and smaller with increased population density.
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Increased emigration: Is a population-decreasing factor.
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Resource availability: Low resource availability leads to population decrease.
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Increased mortality: Is a population-decreasing factor.
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High fertility: Leads to population increase.
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