68 Questions
What is the primary role of mutation in evolution?
Providing the raw material for evolution
How is the effect of mutation on Hardy-Weinberg equilibrium calculated?
p = p - mp & q = q + mp
What does mutation selection balance refer to?
An equilibrium in allele frequency due to mutation and natural selection
What term describes the movement of alleles between populations?
Migration
How does migration relate to gene flow?
Migration facilitates the movement of alleles between populations
In the context of mutation in evolution, what do allele frequencies represent?
Frequency of occurrence of specific genes in a population
How does genetic drift impact smaller populations compared to larger populations?
Genetic drift has a more pronounced effect on smaller populations
What is the relationship between migration and selection in terms of preventing divergence?
Migration prevents divergence due to selection
Why are smaller populations more susceptible to genetic drift?
Because chance events have a greater impact on allele frequencies
In the context of genetic drift, what role does population size play?
Population size determines the rate of genetic drift
What is the founder effect in relation to genetic drift?
It exemplifies genetic drift after a founder event
How does the Hardy-Weinberg equilibrium need to be adjusted to account for drift?
By considering population size and genetic diversity
What makes genetic drift more influential in smaller populations?
Random events having a greater impact in smaller populations
Why does genetic drift have less influence in larger populations?
Larger populations have more individuals, reducing drift's impact
What is the potential consequence of inbreeding on genotype frequencies?
Increase in homozygosity
How does breeding depression relate to the Hardy-Weinberg equilibrium?
It is caused by a deviation from HW equilibrium
What are delayed effects and how are they related to genetic outcomes?
Long-term impacts that may not be immediately noticeable
What does fixation of an allele in a population mean?
All alleles at the locus have been eliminated except one
How can genetic drift lead to fixation of alleles in a population?
Through random sampling leading to allele frequencies of 0 or 1
Which outcome is most likely to occur as a result of genetic drift?
Reduction in genetic diversity
How does genetic drift impact the potential for adaptation in a population?
Reduces the potential for adaptation
What is a consequence of genetic drift on the genetic differences between populations?
Increases genetic differences between populations
How does genetic drift affect the prevalence of harmful alleles in a population?
Increases the prevalence of harmful alleles
What is one potential long-term consequence of increased genetic differences between populations due to genetic drift?
Formation of new species over time
How does genetic drift affect the level of heterozygosity within a population?
Decreases heterozygosity by making less common alleles more prevalent
What insight does the fixation Index provide when studying genetic differentiation?
Extent of genetic diversity between populations
What does effective population size represent in genetic studies?
Size of an ideal random mating population that loses genetic variation at the same rate as an actual population
What is a quantitative trait based on the text provided?
A trait showing continuous variation due to genetics and environment
How do small effect loci contribute to quantitative traits?
They have a significant impact on phenotype despite their small effect
In the context of genetic drift, what can be inferred about populations that are genetically distinct?
They have evolved independently from each other
How does genetic drift impact the genetic relationships between different groups of organisms?
It reveals hidden genetic similarities among organisms
How do codominance and multiple alleles impact quantitative traits?
Increase phenotypic diversity
What is the emphasis of nature in heritability?
Contribution of genetic factors
What is the difference between broad-sense and narrow-sense heritability?
Broad-sense accounts for all genetic effects, narrow-sense only additive genetic effects
Why do we typically use narrow-sense heritability in genetic studies?
It offers a more precise estimate of genetic variance inheritance
Which term best describes broad-sense heritability?
Total phenotypic variance due to genetics
In the context of heritability, what does 'nurture' refer to?
Environmental factors
What does the use of narrow-sense heritability help us determine?
% of genetic variance passed down to offspring
In quantitative genetics, why is narrow-sense heritability preferred over broad-sense heritability?
It specifically measures additive genetic effects.
What does phenotypic plasticity refer to?
The ability of an organism to change its physical characteristics in response to environmental cues
How is phenotypic plasticity described in the context of adaptation?
A flexible trait that helps an organism adjust to its surroundings for improved survival and reproduction
What defines a trade-off in adaptation?
An unavoidable compromise between one trait and another
How do constraints affect adaptation?
Constraints prevent populations from evolving optimal trait values
In the context of adaptation, what is a lack of genetic variation indicative of?
Low potential for evolutionary responses to selective pressures
Why is genetic variation crucial for adaptation?
To provide raw material for natural selection to act upon
What role does environmental influence play in phenotypic plasticity?
It triggers changes in the physical characteristics of an organism
What does behavioral thermoregulation involve?
Using various actions and behaviors to regulate body temperature within a certain range
What defines sexual dimorphism?
A difference in the phenotypes of females versus males within a species
Why does sexual dimorphism exist in some species?
To increase the chances of finding mates and reproducing successfully
What is the primary difference between parental investment by males and females?
Females generally invest more heavily in parental care compared to males
How does sexual selection impact mating success?
It enhances the average mating success of individuals with certain phenotypes
What role do distinct physical characteristics play in enhancing reproductive success?
They increase the likelihood of finding mates and reproducing successfully
In what way do environmental factors contribute to sexual dimorphism?
They impact the expression of genes related to reproductive success
How does parental investment differ between males and females?
Females typically invest more heavily in parental care compared to males
In the context of reproductive success limits, how does sexual selection influence individuals within a population?
By shaping the traits and behaviors individuals exhibit to enhance mating chances
What factor often constrains female reproductive success limits in many species?
Availability of resources and ability to care for offspring
How do reproductive success limits typically vary between males and females?
Males have higher potential reproductive success limits than females
What defines mating success in individuals within a population?
Traits and behaviors that attract potential partners
Why are reproductive success limits important in the context of evolutionary biology?
To study how individuals maximize their chances of passing on their genes
What role do genetic constraints play in shaping reproductive success limits?
They impact the number of offspring an individual can produce
How does sexual selection contribute to the evolution of traits and behaviors in a species?
By favoring traits that enhance mating success and reproduction
What distinguishes mating success from reproductive success in individuals within a population?
The ability to attract potential partners vs. successful offspring production
In which scenario would male-male competition most likely occur?
Males competing for mates during breeding season
What is the main purpose of outright combat among male animals?
To establish dominance over females
Which term describes the sneaker-males mating strategy?
Surreptitious fertilization
What characterizes sperm competition among males?
Competing to fertilize the same female's eggs
Which of the following best defines infanticide?
Killing of offspring by members of the same species
What is the primary motivation for male-male competition during the breeding season?
Gaining access to mates to pass on genes
Study Notes
Genetic Drift and Inbreeding
- Inbreeding increases the likelihood of certain genotypes being passed down from one generation to the next, leading to an increase in homozygosity for certain alleles and affecting the overall genotype frequencies within the population.
- Inbreeding can result in a reduction in genetic diversity and an increased prevalence of genetic disorders.
Breeding Depression
- Breeding depression refers to reduced fitness in individuals or populations resulting from inbreeding.
- It is a potential consequence of deviating from Hardy-Weinberg equilibrium.
Delayed Effects
- Delayed effects refer to the impact or consequences of a certain action or event that are not immediately apparent, but become evident after a significant amount of time has passed.
Fixation
- Fixation is the elimination from a population of all the alleles at a locus but one, leaving the one remaining allele at a frequency of 1.0.
Cumulative Effects of Genetic Drift
- Genetic drift can lead to the fixation of certain alleles, reducing genetic diversity and increasing the prevalence of harmful genetic traits.
- It can also lead to the loss of beneficial alleles, reducing the potential for adaptation and evolution within the population.
Mutation and Selection Balance
- Mutation provides the raw material for evolution.
- Mutation selection balance refers to an equilibrium in the frequency of an allele that occurs because new copies of the allele are created by mutation at exactly the same rate that old copies of the allele are eliminated by natural selection.
Migration and Gene Flow
- Migration refers to the movement of alleles between populations.
- Migration can prevent divergence due to selection.
Genetic Drift and Population Size
- Genetic drift is more pronounced in small populations.
- Smaller populations are more susceptible to genetic drift as chance events have a greater impact on allele frequencies.
Founder Effect
- The founder effect is a specific type of genetic drift that occurs when a small group of individuals from a larger population establish a new population in a different area.
- It is a change in allele frequencies that occurs after a founder event due to genetic drift.
Heterozygosity and Drift
- Genetic drift can have a significant impact on the level of heterozygosity within a population.
Fixation Index
- The fixation index is a measure of genetic differentiation within and between populations.
- It provides insight into the genetic structure of populations and can help identify patterns of gene flow and migration.
Effective Population Size
- The effective population size is the size of an ideal random mating population that would lose genetic variation via drift at the same rate as is observed in an actual population.
Quantitative Traits
- Quantitative traits are determined by the combined influence of the environment and many loci of small effect.
- Codominance and multiple alleles can have significant effects on quantitative traits by increasing the diversity of phenotypes within a population.
Nature vs. Nurture
- Nature emphasizes the role of genetics, while nurture emphasizes the role of the environment in shaping heritable traits.
Heritability
- Broad-sense heritability refers to the total genetic variance in a trait within a population.
- Narrow-sense heritability specifically measures the proportion of genetic variance that is due to additive genetic effects.
Adaptation
- Adaptation refers to the process by which an organism becomes better suited to its environment.
Phenotypic Plasticity
- Phenotypic plasticity is the ability of an organism to change its physical characteristics in response to environmental cues.
- It allows the organism to better survive and reproduce in different environmental conditions.
Trade-Offs and Constraints
- Trade-offs and constraints create the conditions under which trade-offs must be made in order for an organism or system to successfully adapt to its environment.
Sexual Selection
- Sexual selection refers to the differences in average mating success among individuals with different phenotypes.
- It is a key driver of evolutionary change in many species.
Sexual Dimorphism
- Sexual dimorphism refers to the differences between the phenotypes of females versus males within a species.
- It can be influenced by environmental factors and social dynamics within a species.
Parental Investment
- Parental investment refers to the expenditure of time and energy on the provision, protection, and care of an offspring.
- Females typically invest more heavily in parental care compared to males.
Reproductive Success Limits
- Reproductive success limits refer to the maximum number of offspring an individual can produce and successfully raise to adulthood.
- Reproductive success limits vary between males and females due to differences in reproductive strategies and biological constraints.
Mating Success and Reproductive Success
- Mating success refers to an individual's ability to attract and engage in mating behaviors with a potential partner.
- Reproductive success refers to the actual production of offspring.
Week 4: Mutations, Drift, and Migration Week 5: Quantitative Genetics Week 6: Adaptation Week 7: Sexual Selection
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