Podcast
Questions and Answers
What are the three main drivers of population-level evolution?
What are the three main drivers of population-level evolution?
- Natural selection, artificial selection, and genetic drift
- Natural selection, genetic drift, and gene flow (correct)
- Genetic drift, gene flow, and selective breeding
- Gene flow, natural selection, and adaptation
What is the term for the process by which a population's genetic makeup changes due to random chance, particularly affecting small populations?
What is the term for the process by which a population's genetic makeup changes due to random chance, particularly affecting small populations?
- Adaptation
- Genetic drift (correct)
- Gene flow
- Natural selection
Which of the following describes the effect of gene flow on genetic diversity?
Which of the following describes the effect of gene flow on genetic diversity?
- Gene flow always increases genetic diversity by introducing new alleles.
- Gene flow has no effect on genetic diversity, as alleles are simply transferred between populations.
- Gene flow always decreases genetic diversity by homogenizing populations.
- Gene flow can either increase or decrease genetic diversity depending on the specific alleles involved. (correct)
What is a bottleneck in the context of population genetics?
What is a bottleneck in the context of population genetics?
What is the primary reason why genetic drift has a more pronounced effect on smaller populations?
What is the primary reason why genetic drift has a more pronounced effect on smaller populations?
What is the founder effect?
What is the founder effect?
Which of the following is NOT a type of natural selection?
Which of the following is NOT a type of natural selection?
Which of these is an example of human-induced genetic drift?
Which of these is an example of human-induced genetic drift?
Which of the following statements is TRUE about the effects of genetic drift?
Which of the following statements is TRUE about the effects of genetic drift?
What is the term for the ability of an organism to change its phenotype in response to environmental changes?
What is the term for the ability of an organism to change its phenotype in response to environmental changes?
What is the primary mechanism by which gene flow occurs?
What is the primary mechanism by which gene flow occurs?
How does genetic drift differ from natural selection?
How does genetic drift differ from natural selection?
Which of the following human activities can contribute to genetic drift?
Which of the following human activities can contribute to genetic drift?
What is the main idea behind the concept of genetic drift?
What is the main idea behind the concept of genetic drift?
What is a key difference between genetic drift and natural selection?
What is a key difference between genetic drift and natural selection?
Which of the following is an example of the founder effect?
Which of the following is an example of the founder effect?
What is a potential consequence of genetic drift?
What is a potential consequence of genetic drift?
How does size-selective harvesting impact populations?
How does size-selective harvesting impact populations?
What is a potential consequence of trophy hunting?
What is a potential consequence of trophy hunting?
How can genetic drift affect the long-term survival of a population?
How can genetic drift affect the long-term survival of a population?
In the example of the Tiburon Island desert bighorn sheep population, what is a likely factor that contributed to the increase in population size?
In the example of the Tiburon Island desert bighorn sheep population, what is a likely factor that contributed to the increase in population size?
Flashcards
Genetic Drift
Genetic Drift
Random changes in allele frequencies in a population over time due to chance events.
Founder Effect
Founder Effect
A phenomenon where a small group becomes isolated and establishes a new population with different allele frequencies.
Isolation
Isolation
When a small group of individuals becomes separated from the larger parent population.
Desert Bighorn Sheep Example
Desert Bighorn Sheep Example
A study showing how a small founder population increased significantly in size over time.
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Human-Induced Genetic Drift
Human-Induced Genetic Drift
Changes in allele frequencies caused by human activities, such as selective harvesting.
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Selective Harvesting
Selective Harvesting
The practice of harvesting individuals based on specific traits, often size or attributes, affecting population genetics.
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Trophy Hunting
Trophy Hunting
A hunting practice where individuals harvest animals for sport, often targeting individuals with desirable traits.
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Size-selective Fishing Example
Size-selective Fishing Example
Fishing methods that only catch larger individuals, impacting the overall genetic makeup of fish populations.
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Microevolution
Microevolution
Small-scale evolutionary changes within a population over time.
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Natural selection
Natural selection
Process where organisms better adapted to their environment tend to survive and produce more offspring.
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Bottleneck effect
Bottleneck effect
Sharp reduction in population size due to environmental events or human activities, leading to decreased genetic diversity.
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Phenotypic plasticity
Phenotypic plasticity
The ability of an organism to change its phenotype in response to environmental changes.
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Types of Natural Selection
Types of Natural Selection
Includes directional, disruptive, and stabilizing selection, mechanisms that drive evolution.
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Costs and Benefits of Gene flow
Costs and Benefits of Gene flow
Movement of genes between populations can introduce new alleles but also can disrupt local adaptations.
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Effects of Genetic Drift
Effects of Genetic Drift
Can change allele frequencies randomly, reducing variation, and fixing harmful alleles.
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Gene Flow
Gene Flow
Transfer of alleles between populations through movement of individuals or gametes.
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Beneficial Gene Flow
Beneficial Gene Flow
Increases genetic diversity by introducing new alleles into a population.
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Harmful Gene Flow
Harmful Gene Flow
Potentially decreases local adaptation by blending different populations.
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Microevolution - Key Drivers
- Natural selection: Adaptations change allele frequencies
- Genetic drift: Chance events alter allele frequencies
- Gene flow: Transfer of alleles between populations
Microevolution - Natural Selection
- Driving force of evolution
- Individuals with traits better suited to their environment have higher survival and reproductive rates.
- Over generations, beneficial traits become more common.
Microevolution - Genetic Drift
- Random changes in allele frequencies
- Significant in small populations.
- Chance events (e.g., natural disasters, disease outbreaks, or founder effect) can drastically alter allele frequencies.
- Bottlenecks: drastic reduction in population size leads to loss of genetic variation.
- Founder effect: establishing a new population from a small group can lead to reduced genetic diversity compared to the original population.
- Examples: Northern elephant seals, California condors
Microevolution - Gene Flow
- Movement of alleles between populations.
- Individuals migrating between populations introduce new alleles or change the proportion of existing alleles.
- Increases genetic diversity in recipient populations.
- Examples: Wind pollination, animal migration, dispersal of seeds by animals
- Importance in conservation biology
Human-Induced Selective Harvesting
- Selective harvesting (e.g., trophy hunting, fisheries) can impact populations.
- Often, individuals with specific traits (based on size or other characteristics) are targeted.
- Can lead to significant genetic consequences altering the genetic diversity in the population.
- Examples: Trophy hunting of bighorn sheep, fisheries targeting larger fish
Genetic Drift - Consequences
- Significant in small populations
- Random changes in allele frequencies
- Loss of genetic variation.
- Harmful alleles can become fixed, while beneficial alleles can be lost.
- Examples: Greater prairie chickens (Illinois population), which lost considerable genetic variation due to a drastic population decline from the 1800s to the 1990s.
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Description
This quiz explores the key drivers of microevolution, including natural selection, genetic drift, and gene flow. Understand how these mechanisms influence allele frequencies and contribute to evolutionary changes in populations. Test your knowledge on these fundamental concepts of evolutionary biology.