Coevolution, Arms Races, and Ecological Evolutionary Dynamics
Evolution in Interaction Networks
What coevolution is
Coevolution occurs when two or more species reciprocally influence one another's evolution. This can happen between predators and prey, hosts and parasites, mutualists and partners, or plants and pollinators.
Arms races and diffuse coevolution
Reciprocal selection can produce escalating traits such as defense and counter-defense. In some systems, selection acts on whole communities rather than strict one-to-one pairs, producing diffuse coevolution.
Ecological feedback
Trait evolution can alter ecological interactions, which then change the selective environment and drive further evolution.
Which pairing is a classic example of coevolution?
Reciprocal adaptation between interacting species is the essence of coevolution.
Correct answer: Predator and prey with reciprocal adaptations
How can mutualism involve coevolution?
Mutualisms often involve reciprocal adaptation, not just conflict.
Correct answer: Each partner can evolve traits that improve the interaction, and those traits then change selection on the other partner.
Interaction outcomes
Antagonistic coevolution
- Each species reduces the fitness of the other
- Often produces arms-race dynamics
Mutualistic coevolution
- Each species benefits the other
- Can favor specialization or cooperation
Red Queen dynamics
In some interactions, species must continually evolve just to maintain their relative performance because partners and enemies are also changing. This helps explain why static trait values can be temporary in competitive systems.
What is the best description of the Red Queen hypothesis?
The Red Queen idea emphasizes ongoing evolutionary change driven by interacting species.
Correct answer: Species must keep evolving to maintain relative fitness in changing biotic environments
Analyzing a coevolutionary system
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1
Identify the interacting species.
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2
Ask whether each exerts reciprocal selection on the other.
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3
Determine whether the interaction is antagonistic or mutualistic.
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4
Consider whether trait change may be rapid and cyclical.