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Questions and Answers
What is the primary consequence of low genetic diversity in small populations?
Which evolutionary force is NOT directly involved with the selection of traits in a population?
What role does genetic rescue play in species conservation?
Which factor can severely impact species with low MHC diversity?
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How does loss of self-incompatibility alleles affect plant populations?
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Which of the following statements about genetic drift is true?
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What is a key effect of an extinction vortex?
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Why are small populations at a greater risk of extinction?
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What is one potential consequence of low genetic diversity in small populations?
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The process by which allele frequencies can fluctuate due to random chance is known as _____ drift.
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Natural selection and genetic drift are the same evolutionary forces.
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Which of the following is NOT an evolutionary force mentioned?
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What does 'fitness' refer to in the context of reproduction and survival?
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Loss of self-incompatibility alleles can lead to increased fitness in plant populations.
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Match the following terms with their descriptions:
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How does low MHC diversity affect species?
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Environmental extremes can challenge species with low genetic diversity, reducing their _____ potential.
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In the context of genetic diversity, what does Ne represent?
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Study Notes
Genetic Diversity and Extinction
- Extinction and Genetic Diversity: Reduced genetic diversity increases the risk of extinction.
- Fitness: Reproduction and survival are key components of fitness.
- Small Populations: Small populations often have low genetic diversity, leading to reduced evolutionary potential, vulnerability to environmental changes, and increased susceptibility to diseases.
- Self-Incompatibility: Loss of self-incompatibility alleles in small plant populations reduces their fitness.
- MHC: Low MHC diversity can make species highly vulnerable to pests, parasites, and infectious diseases.
- Evolutionary Forces: Mutation, migration/gene flow, natural selection, and genetic drift are key evolutionary forces.
- Neutral Alleles: Neutral alleles, not subject to selection, can drift in frequency over time, eventually becoming lost or fixed in a population.
- Genetic Rescue: Introducing genetic diversity through external populations can rescue declining populations by providing new genetic variation.
- Consequences of Loss of Genetic Diversity: Reduced fitness and increased susceptibility to extinction are major consequences.
Post-2020 Global Biodiversity Framework
- Effective Population Size (Ne): Important factor influencing genetic diversity.
- Ne and H-Loss: Effective population size (Ne) and haplotype diversity (H) are key measures when evaluating genetic diversity and risk of genetic loss.
Genetic Diversity and the Extinction Vortex
- Reduced Evolutionary Potential: Low genetic diversity leads to limited adaptive capacity and a reduced ability to cope with environmental changes.
Genotypes, Phenotypes, Environment, and Plasticity
- Genotype: An individual's genetic makeup.
- Phenotype: An individual's observable characteristics, influenced by both genotype and environment.
- Plasticity: The ability of an organism to change its phenotype in response to environmental conditions.
Key Take Home Messages
- Genetic diversity is crucial for species survival.
- Small populations often have low genetic diversity and are more vulnerable to extinction.
- Environmental changes, like climate change, can further impact the genetic diversity of species.
Class Assignment
- Conservation: Identify a species of conservation concern.
- Factors Contributing to Vulnerability: Analyze how the interaction of its biological traits and environmental factors (like climate change) contribute to its risk of extinction.
Genetic Diversity & Extinction
- Extinction is linked to genetic diversity & variation.
- Reproduction and survival contribute to fitness.
- Small populations may have low genetic diversity, resulting in reduced evolutionary potential, poor ability to cope with environmental extremes and infectious diseases compared to populations with higher genetic diversity.
- Loss of self-incompatibility alleles in small plant populations leads to reduced fitness.
- MHC with low diversity may cause species to suffer dramatically from outbreaks of pests, parasites, and infectious diseases.
Evolutionary Forces
- Mutation: A change in the DNA sequence.
- Migration and gene flow: Movement of individuals and their genes between populations.
- Natural selection: Differential survival and reproduction of individuals based on traits.
- Genetic drift: Random changes in allele frequencies, especially prominent in small populations.
Genetic Drift
- Neutral alleles can drift in frequency for extended periods before becoming lost or fixed in a population.
Natural Selection
- Natural selection acts on the phenotypic variation influenced by underlying genetic differences.
Genetic Rescue
- Introduces new genetic variation into a population to increase fitness and reduce risk of extinction.
Consequences of Genetic Diversity Loss
- Reduced fitness
- Increased extinction risk
- Decreased adaptability to environmental changes
Ne and H-loss
- Effective population size (Ne) is a measure of the number of individuals contributing genes to the next generation.
- Ne can be smaller than the actual population size due to factors such as uneven sex ratios and inbreeding.
- Loss of genetic diversity (H) reduces evolutionary potential and increases extinction risks.
Genetic Diversity and Extinction Vortex
- Loss of genetic diversity leads to reduced evolutionary potential, increasing vulnerability to environmental changes and extinction.
Genotypes, Phenotypes, Environment, and Plasticity
- Genotype (genetic makeup) influences the phenotype (observable traits).
- Phenotypes can be influenced by environment and plasticity, allowing individuals to adjust to changing environmental condition.
Key Take Home Messages
- Genetic diversity is crucial for survival and adapting to changing environments.
- Small populations are more vulnerable to genetic drift and loss of diversity.
- Conservation efforts should focus on maintaining genetic diversity to prevent extinction.
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Description
Test your knowledge on the relationship between genetic diversity and extinction. This quiz covers key concepts about fitness, small populations, and the impact of evolutionary forces on genetic variability. Explore the implications for species survival and management strategies like genetic rescue.
