Introduction to Ecology and Evolutionary Biology
Introduction
Professor Nicole Medeiro from the department of Ecology and Evolutionary Biology.
Studies ecology and evolution of infectious diseases, focusing on traits of pathogens influencing infectiousness and disease severity.
Uses mathematical modeling to explore how control efforts can affect pathogen evolution.
Course Overview
Exploration of evolutionary causes and consequences of variation in traits and behaviors across different organisms.
Topics include:
Understanding the origins of phenotypes, emphasizing behaviors.
Examining sexual traits and behaviors, including variation between sexes.
Exploring social evolution through cooperation and conflict.
Applying evolutionary perspectives to health and disease, including topics like aging and pathogen evolution.
Understanding Phenotypes and Behaviors
Phenotypes result from both genetic and environmental influences.
Natural selection shapes behaviors similar to other traits.
Environmental effects lead to plasticity; traits or behaviors can change according to environmental conditions.
Examples of both adaptive and maladaptive plasticity in behaviors.
Adaptive plasticity: changes that improve fitness or survival.
Maladaptive plasticity: changes that do not confer advantages.
Types of Questions in Biology
How/What Questions (Mechanistic):
Focus on mechanisms behind traits and behaviors.
E.g., How do aggressive behaviors in elk manifest biologically?
Why Questions (Ultimate):
Address evolutionary reasons for traits and behaviors.
E.g., Why has aggressive behavior evolved in elk?
Case Study: Fruit Fly Polymorphism
Polymorphism: trait variation exists within a species.
Focus on the foraging gene affecting behaviors in fruit flies, categorized into:
Rovers: larvae that move significantly more.
Sitters: larvae that remain relatively stationary.
Environmental conditions (food presence) influence these behaviors:
When food is available, sitters may do well, whereas rovers may thrive when food is scarce.
Genetic Basis of Behavior
The Rover-Sitter polymorphism is influenced by a single nucleotide polymorphism (SNP) in the foraging gene.
Different alleles correspond to different behaviors.
Gene expression levels influence the outcome of foraging behavior.
Environmental Influences on Behavior
Example: Food deprivation in fruit flies influences movement:
Rovers move farther than sitters, but both reduce activity when food-deprived longer.
Reaction norms: graphical depiction showing how the phenotype of a single genotype responds to environmental changes.
Plasticity and Reaction Norms
Interaction of genotype and environment demonstrated via reaction norms, showing different responses to environmental stimuli.
Adaptive plasticity encourages favorable adjustments in behavior that improve existence in challenging environments.
Evolution of Plasticity Examples
Daphnia genus exhibits behavioral plasticity based on predation cues.
Differences in behavior correlated with historical exposure to predators:
Lakes with predation history show adaptations in behavior to avoid risks.
Visualization of how populations evolve in response to threats through shifts in reaction norms.
Conclusion
Understanding phenotypes and behaviors requires integrated consideration of genetic and environmental effects.
Real-world implications exist for health and disease processes based on evolutionary perspectives.
Introduction - Professor Nicole Medeiro from the department of Ecology and Evolutionary Biology. - Studies ecology and evolution of infectious diseases, focusing on traits of pathogens influencing infectiousness and disease severity. - Uses mathematical modeling to explore how control efforts can affect pathogen evolution.
Course Overview - Exploration of evolutionary causes and consequences of variation in traits and behaviors across different organisms. - Topics include: - Understanding the origins of phenotypes, emphasizing behaviors that can range from simple reflexes to complex social structures. - Examining sexual traits and behaviors, including variation between sexes and how these adaptations facilitate reproductive success. - Exploring social evolution through cooperation and conflict, particularly in species that thrive in social groups. - Applying evolutionary perspectives to health and disease, including topics like aging, pathogen evolution, and the impact of human behavior on these processes.
Understanding Phenotypes and Behaviors - Phenotypes result from both genetic and environmental influences, demonstrating the complexity of trait development. - Natural selection shapes behaviors similar to other traits by selecting individuals that exhibit beneficial behaviors. - Environmental effects lead to plasticity; traits or behaviors can change according to environmental conditions, allowing for adaptive responses. - Examples of both adaptive and maladaptive plasticity in behaviors. - Adaptive plasticity: changes that improve fitness or survival in fluctuating environments. - Maladaptive plasticity: changes that do not confer advantages or may even reduce fitness in the long term.
Types of Questions in Biology 1. How/What Questions (Mechanistic): - Focus on mechanisms behind traits and behaviors at a biological level. - E.g., How do aggressive behaviors in elk manifest biologically in their physiology and brain structure? 2. Why Questions (Ultimate): - Address evolutionary reasons for traits and behaviors, considering fitness advantages. - E.g., Why has aggressive behavior evolved in elk, possibly related to competition for mates and resources?
Case Study: Fruit Fly Polymorphism - Polymorphism: trait variation exists within a species, allowing for adaptable strategies in different environments. - Exploration of the foraging gene affecting behaviors in fruit flies, categorized into: - Rovers: larvae that move significantly more, enabling them to search wider areas for food. - Sitters: larvae that remain relatively stationary, which may conserve energy when food is abundant. - Environmental conditions (food presence) influence these behaviors: - When food is available, sitters may do well by being more efficient, whereas rovers may thrive when food is scarce, capitalizing on resource scarcity.
Genetic Basis of Behavior - The Rover-Sitter polymorphism is influenced by a single nucleotide polymorphism (SNP) in the foraging gene. - Different alleles correspond to different behaviors, indicating a direct link between genetics and observable outcomes. - Gene expression levels influence the outcome of foraging behavior, with variances leading to behavioral diversity.
Environmental Influences on Behavior - Example: Food deprivation in fruit flies influences movement: - Rovers move farther than sitters, indicating a behavioral strategy to find scarce resources, but both reduce activity when food-deprived longer to conserve energy. - Reaction norms: graphical depiction showing how the phenotype of a single genotype responds to environmental changes, capturing the interplay of genetics and environment on behavior.
Plasticity and Reaction Norms - Interaction of genotype and environment demonstrated via reaction norms, showing different responses to environmental stimuli across multiple contexts. - Adaptive plasticity encourages favorable adjustments in behavior that improve existence in challenging environments, leading to higher survival rates.
Evolution of Plasticity Examples - Daphnia genus exhibits behavioral plasticity based on predation cues, showcasing how past environmental pressures shape current behavior. - Differences in behavior correlated with historical exposure to predators: - Lakes with predation history show adaptations in behavior to avoid risks, highlighting evolutionary responses to survival threats. - Visualization of how populations evolve in response to threats through shifts in reaction norms, reflecting the dynamic nature of evolutionary change.
Conclusion - Understanding phenotypes and behaviors requires integrated consideration of genetic and environmental effects, emphasizing the importance of both in evolutionary biology. - Real-world implications exist for health and disease processes based on evolutionary perspectives, demonstrating the relevance of these concepts in practical applications such as epidemiology and conservation biology.