Podcast
Questions and Answers
What is the main characteristic of Type III survivorship?
What is the main characteristic of Type III survivorship?
- Constant death rates across all age groups
- Low mortality rates in young
- Parental care leading to high survival rates
- High mortality for the young followed by a plateau in adults (correct)
In exponential population growth, which factor does NOT influence the change in population size?
In exponential population growth, which factor does NOT influence the change in population size?
- Industrial pollution (correct)
- Number of deaths
- Number of immigrants
- Number of births
What denotes the carrying capacity (K) in a habitat?
What denotes the carrying capacity (K) in a habitat?
- The number of individuals that can migrate to a new area
- The maximum population size that can be sustained (correct)
- The point at which resources are infinite
- The initial population size before growth starts
Which equation represents the change in population size over time?
Which equation represents the change in population size over time?
Which of the following best describes exponential growth?
Which of the following best describes exponential growth?
What does 'r' represent in the context of population growth?
What does 'r' represent in the context of population growth?
Which scenario is most likely to lead to exponential population growth?
Which scenario is most likely to lead to exponential population growth?
What is primarily responsible for limiting logistic growth?
What is primarily responsible for limiting logistic growth?
What is the first step in the mark-recapture method for estimating population size?
What is the first step in the mark-recapture method for estimating population size?
Which formula is used to estimate the population size in the mark-recapture method?
Which formula is used to estimate the population size in the mark-recapture method?
What is a key assumption made in mark-recapture methods?
What is a key assumption made in mark-recapture methods?
What does the variable 's' represent in the mark-recapture method?
What does the variable 's' represent in the mark-recapture method?
Which of the following factors contribute positively to changes in population size?
Which of the following factors contribute positively to changes in population size?
After marking and releasing individuals, what is the next action to take in the mark-recapture process?
After marking and releasing individuals, what is the next action to take in the mark-recapture process?
What is the purpose of counting the number m of re-sampled marked individuals?
What is the purpose of counting the number m of re-sampled marked individuals?
What is the primary purpose of a life table in demographics?
What is the primary purpose of a life table in demographics?
Which of the following statements accurately reflects the mark-recapture method?
Which of the following statements accurately reflects the mark-recapture method?
Which type of survivorship curve is characterized by a low death rate in juveniles and adults?
Which type of survivorship curve is characterized by a low death rate in juveniles and adults?
What is demography primarily concerned with studying?
What is demography primarily concerned with studying?
Why is it often impossible to count all individuals in a population?
Why is it often impossible to count all individuals in a population?
Which characteristic is NOT associated with K-selection?
Which characteristic is NOT associated with K-selection?
What do K-selection strategies generally favor?
What do K-selection strategies generally favor?
What is one common misconception regarding K and r strategies?
What is one common misconception regarding K and r strategies?
In the context of life history trade-offs, which statement is true regarding r strategies?
In the context of life history trade-offs, which statement is true regarding r strategies?
What factor may influence the evolution of life-history traits according to the recent understanding in ecology?
What factor may influence the evolution of life-history traits according to the recent understanding in ecology?
What does the logistic growth model express?
What does the logistic growth model express?
Which statement best describes competition in K-selection environments?
Which statement best describes competition in K-selection environments?
Which of the following is an example of a K-strategy organism?
Which of the following is an example of a K-strategy organism?
What is a life history trait that impacts an organism's schedule of reproduction and survival?
What is a life history trait that impacts an organism's schedule of reproduction and survival?
Which of the following is a characteristic of r-selection life history strategies?
Which of the following is a characteristic of r-selection life history strategies?
What is one of the trade-offs observed in life history traits regarding offspring?
What is one of the trade-offs observed in life history traits regarding offspring?
In the logistic growth model, what is expected to happen if a population overshoots its carrying capacity K?
In the logistic growth model, what is expected to happen if a population overshoots its carrying capacity K?
Which of the following best describes a phenotypic negative correlation?
Which of the following best describes a phenotypic negative correlation?
What defines the r-selection in population ecology?
What defines the r-selection in population ecology?
Which factor is NOT a life history trait?
Which factor is NOT a life history trait?
What do life history trade-offs imply about resource allocation?
What do life history trade-offs imply about resource allocation?
What does population ecology primarily study?
What does population ecology primarily study?
What is the main purpose of the mark-recapture method?
What is the main purpose of the mark-recapture method?
Which factor is NOT typically analyzed in population dynamics?
Which factor is NOT typically analyzed in population dynamics?
Which curve is associated with survivorship based on life tables?
Which curve is associated with survivorship based on life tables?
What is a key difference between exponential and logistic growth models?
What is a key difference between exponential and logistic growth models?
How can life history traits influence an individual’s fitness?
How can life history traits influence an individual’s fitness?
Which of the following is true regarding trade-offs in life history traits?
Which of the following is true regarding trade-offs in life history traits?
Which method is primarily used to extrapolate population sizes from a sub-sample?
Which method is primarily used to extrapolate population sizes from a sub-sample?
Flashcards
Population ecology
Population ecology
The study of populations in relation to their environment, including factors like density, distribution, age structure, and population size variations.
Population dynamics
Population dynamics
The study of how interactions between biotic(living) and abiotic (non-living) factors influence changes in a population's size.
Mark-recapture method
Mark-recapture method
A method to estimate population size by capturing, marking, releasing, and recapturing individuals in a sample.
Population
Population
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Estimating population size
Estimating population size
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Mark-recapture method: step 1
Mark-recapture method: step 1
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Mark-recapture method: step 2
Mark-recapture method: step 2
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Mark-recapture method: step 3
Mark-recapture method: step 3
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Sample individuals
Sample individuals
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Mark all sampled individuals
Mark all sampled individuals
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Resample individuals
Resample individuals
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Count re-sampled marked individuals
Count re-sampled marked individuals
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Population size estimation
Population size estimation
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Estimation formula
Estimation formula
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Extrapolation
Extrapolation
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Mark-Recapture Assumptions
Mark-Recapture Assumptions
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Population Density Change
Population Density Change
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Demography
Demography
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Life Table
Life Table
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Survivorship Curve
Survivorship Curve
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Type III Survivorship Curve
Type III Survivorship Curve
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Exponential Growth
Exponential Growth
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What is the equation for exponential growth?
What is the equation for exponential growth?
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Intrinsic Growth Rate (r)
Intrinsic Growth Rate (r)
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Logistic Growth
Logistic Growth
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Carrying Capacity (K)
Carrying Capacity (K)
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What are the limitations of exponential growth?
What are the limitations of exponential growth?
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What is the key difference between exponential and logistic growth?
What is the key difference between exponential and logistic growth?
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Life history traits
Life history traits
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Trade-off in Life History
Trade-off in Life History
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r-selection
r-selection
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K-selection
K-selection
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Influence of density on selection
Influence of density on selection
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Density-independent selection
Density-independent selection
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Density-dependent selection
Density-dependent selection
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Examples of r-selection
Examples of r-selection
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Life History Trade-offs
Life History Trade-offs
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r-strategy
r-strategy
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K-selected species
K-selected species
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r-selected species
r-selected species
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Ecological Succession
Ecological Succession
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Study Notes
Topic 15: Population Ecology
- Population ecology is the study of populations in relation to their environment, including factors like density, distribution, age structure, and population size variation.
- Population dynamics investigates how biotic and abiotic factors influence population size changes.
- A population is a group of individuals of a single species living in the same area and interbreeding to produce fertile offspring.
Learning Outcomes
- Estimate population size using the mark-recapture method.
- Graphically analyze population demographics over time.
- Identify survivorship curves based on demographic parameters from a life table.
- Compare and contrast exponential and logistic population growth models.
- Evaluate growth model parameters to predict population size changes.
- Explain how life history traits impact lifetime fitness.
- Graphically identify trade-offs in life history traits.
Estimating Population Size
- Often, counting all individuals in a population is impossible.
- A sub-sample is used and extrapolated to estimate the whole population.
- Mark-recapture method:
- Sample a number of individuals (s).
- Mark all sampled individuals.
- Release the marked individuals.
- Resample a number of individuals (r).
- Count the number of re-sampled marked individuals (m).
- Use the formula N = (s × r) / m to estimate population size (N).
Population Density
- Population density is the number of individuals per unit area or volume, and it can change over time.
- Population density change is influenced by immigration/births and emigration/deaths.
- Change in population size = births + immigrants - deaths - emigrants
Demographics
- Demography is the study of changes in vital statistics over time (like birth rates, death rates) within populations, especially birth rates and death rates.
- A life table can summarize the survival and reproduction rates of individuals across specific age groups within a population.
- A life table typically tracks a cohort (individuals born around the same time), particularly females, because they tend to be the ones producing offspring.
- Life tables reveal constant death rates and higher reproduction rates at specific ages (e.g., age 4 in the Belding's ground squirrel example).
Survivorship Curves
- Survivorship curves show the proportion of individuals in a cohort that remain alive at each age.
- Type I curves show a high survival rate in juveniles and adults, followed by a sharp decline in old age (mammals, few offspring, parental care).
- Type II curves display a relatively constant death rate across all ages (e.g., certain birds).
- Type III curves illustrate high mortality rates for young but a leveling off of death rates among surviving individuals into adulthood (fish, many offspring, no parental care).
Modeling Population Growth
- Exponential growth occurs in ideal, unlimited environments, where the population size increases by a constant proportion each time interval. The population size over time follows a J-shaped curve.
- Logistic growth occurs when resources are finite. Initial growth is exponential but slows as the population approaches the carrying capacity (K), the maximum population size a particular environment can sustain, forming an S-shaped growth curve over time. Logistic growth is influenced by environmental limits that affect per capita birth rates and/or death rates
Life History Traits
- Life history traits are the characteristics determining the schedule of reproduction and survival in an organism. Examples include:
- Mass at birth
- Age at sexual maturity
- Frequency of reproduction
- Reproductive lifespan
- Number of offspring
- Investment in parental care
- Age at death (longevity)
Life History Trade-offs
- Organisms allocate finite resources to different life history traits, often resulting in trade-offs.
- Examples include the trade-off between the number of offspring and the resources invested in each offspring. Egg size and fecundity show phenotypic negative correlations.
- r-selected species (low densities): Short lifespan, high reproductive rate, many small offspring, few reproductive events, high mortality rate, and minimal parental care.
- K-selected species (high densities): Longer lifespan, low reproductive rate, few large offspring, frequent reproduction, low mortality rate and high parental care
Summary
- Population ecology studies populations' relationship to their environment. Key aspects include population dynamics, estimating size, demographics (like survivorship curves), modeling growth (exponential/logistic), life history traits, and trade-offs between them. These factors impact population size over time.
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