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Questions and Answers
Which characteristic is most indicative of K-selected species?
Which characteristic is most indicative of K-selected species?
What is an example of mimicry in the animal kingdom?
What is an example of mimicry in the animal kingdom?
Which term describes the interaction where both species benefit?
Which term describes the interaction where both species benefit?
In which type of competition do individuals of the same species engage?
In which type of competition do individuals of the same species engage?
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Which strategy typically exhibits logistical growth?
Which strategy typically exhibits logistical growth?
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What does camouflage help an organism to achieve?
What does camouflage help an organism to achieve?
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What type of ecological succession begins on bare rock?
What type of ecological succession begins on bare rock?
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Which relationship is characterized by one organism benefiting at the expense of another?
Which relationship is characterized by one organism benefiting at the expense of another?
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What is a primary cause of population interactions and ecosystem balance?
What is a primary cause of population interactions and ecosystem balance?
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What feature is most associated with r-selected strategies?
What feature is most associated with r-selected strategies?
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Which of the following factors is NOT involved in affecting allele frequencies in a population?
Which of the following factors is NOT involved in affecting allele frequencies in a population?
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What is the formula for calculating population density?
What is the formula for calculating population density?
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Which population distribution pattern sees organisms evenly spaced over an area?
Which population distribution pattern sees organisms evenly spaced over an area?
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What does the ΔN formula represent in population change calculations?
What does the ΔN formula represent in population change calculations?
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What type of growth pattern is represented by a logistical growth model?
What type of growth pattern is represented by a logistical growth model?
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Which of the following best describes density-dependent factors?
Which of the following best describes density-dependent factors?
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What characteristic is NOT typical of r-selected strategies?
What characteristic is NOT typical of r-selected strategies?
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What is an example of density-independent factors affecting population fluctuations?
What is an example of density-independent factors affecting population fluctuations?
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What is the primary effect of the founder effect on allele frequencies?
What is the primary effect of the founder effect on allele frequencies?
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What does the variable 'K' represent in population ecology?
What does the variable 'K' represent in population ecology?
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What is the importance of the 'gene pool' in a population?
What is the importance of the 'gene pool' in a population?
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Which equation represents the calculation of allele frequency?
Which equation represents the calculation of allele frequency?
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Under what condition will a population be in Hardy-Weinberg equilibrium?
Under what condition will a population be in Hardy-Weinberg equilibrium?
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Which of the following statements about the Hardy-Weinberg Principle is true?
Which of the following statements about the Hardy-Weinberg Principle is true?
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What does a genotype frequency indicate?
What does a genotype frequency indicate?
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Which of the following is NOT a condition for Hardy-Weinberg equilibrium?
Which of the following is NOT a condition for Hardy-Weinberg equilibrium?
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In the Hardy-Weinberg equation, what does 'p2' represent?
In the Hardy-Weinberg equation, what does 'p2' represent?
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Which of the following best describes genetic drift?
Which of the following best describes genetic drift?
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How does gene flow impact a population's allele frequency?
How does gene flow impact a population's allele frequency?
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Which type of competition occurs within the same species?
Which type of competition occurs within the same species?
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Study Notes
Population and Community Dynamics
- Possible diploma questions include Hardy-Weinberg calculations and conditions, gene flow/genetic drift, density-dependent/independent and inter/intra competition, symbiosis, growth curves/carrying capacity, S vs J curves, K vs r-selected strategies, and population/community/succession calculations.
Hardy-Weinberg Principle
- The principle states that the genetic composition of a population remains constant from one generation to the next if there are no forces affecting allele frequency. This means no evolution is occurring. In other words, consistent allele frequencies.
- Allele frequency calculation: p+q=1, where p is the dominant and q is the recessive allele frequency.
- Genotype frequency calculation: p² + 2pq + q² = 1, where p² is the homozygous dominant, 2pq is the heterozygous and q² is the homozygous recessive.
Conditions of Hardy-Weinberg Equilibrium
- Population is large enough that chance events do not affect allele frequencies.
- Mating is random.
- No new mutations.
- No migration.
- No natural selection against any phenotypes.
Forces that affect Allele Frequencies
- Genetic drift
- Founder effect
- Bottleneck effect
- Gene flow
- Mutations
- Natural Selection
- Sexual Selection
Population Changes
- Populations are described by size or density.
- Population density calculation: D = N/A where D is density, N is the number of individuals and A is the area represented.
- Patterns of population distribution can be clumped, random or uniform.
- Factors affecting population size changes include birth rate/natality, immigration, death rate/mortality, and emigration.
Calculating Change in Population Size
- ΔN = (factors increasing pop.) - (factors decreasing pop.), where ΔN is the change in size of a population and factors are the factors identified above that impact population growth.
Calculating Growth Rate
- Growth rate is the increase in individuals over a specific time period.
- Gr = ΔN/Δt, where gr is the growth rate, ΔN is the change in population size and Δt is the time period of the change.
- The per capita growth rate describes the change in population compared to the initial population.
- cgr = ΔN/N, where cgr is the per capita growth rate
Carrying Capacity
- Carrying capacity (K) is the maximum number of individuals that a given environment can support.
- Logistic growth displays an S-shape curve.
- Population fluctuations are caused by:
- Density-dependent factors (competition, predation, disease)
- Density-independent factors (floods, drought)
Exponential Growth
- Exponential growth occurs in the absence of limiting factors.
Life Strategies
- r-selected strategies are characterized by short lifespans, early reproductive ages, high biotic potential (produce many offspring quickly), minimal parental investment, exponential growth, and tend to have smaller body sizes.
- K-selected strategies are characterized by long lifespans, late reproductive ages, low biotic potential (produce small numbers of offspring less frequently), considerable parental investment, often displays logistical growth and tend to have larger body sizes.
Population Interactions
- Mimicry is when one organism resembles another.
- Camouflage allows organisms to blend in with their surroundings.
- Chemical defense is a toxin change that can avoid being eaten.
- Predator-prey interactions are essential but result in cyclical changes in population sizes.
- Competition can be:
- Interspecific (between different species)
- Intraspecific (between individuals of the same species)
- Symbiotic Relationships can be:
- Mutualism (both benefit)
- Commensalism (one benefits, other is unaffected)
- Parasitism (one benefits, other is harmed)
Ecological Succession
- Primary succession begins from bare rock.
- Secondary succession begins following an ecological disturbance.
- The final stage is the climax community, which is stable and balanced.
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Description
Test your knowledge on key concepts of population and community dynamics, including the Hardy-Weinberg principle, gene flow, and competition types. This quiz covers essential calculations and the conditions necessary for Hardy-Weinberg equilibrium. Ideal for students studying ecology and evolution.
