Rucete ✏ Campbell Biology In a Nutshell
Unit 8 ECOLOGY — Concept 52.5 Ecological Change and Evolution Affect One Another Over Short and Long Time Scales
Ecological and evolutionary processes are intertwined: ecological conditions influence evolution, and evolutionary changes can reshape ecosystems. This feedback can occur over both millions of years and within a few generations, leading to dynamic shifts in community structure and function.
1. Long-Term Eco-Evolutionary Feedback
- Ecological interactions can lead to evolutionary change, and vice versa
- Example: the origin of plants altered atmospheric carbon and nutrient cycles
- New plant species provided new habitats and food, triggering animal diversification
- Evolution of one group (plants) spurred ecological change, which then led to further evolution (insects, animals)
2. Mid-Term Evolutionary Effects
- Over centuries or millennia, reciprocal effects are also evident
- Example:
- Mosquitofish adapted to predation pressure
- Apple maggot flies adapted to human-introduced apple trees
- These examples show how ecological opportunities or pressures shape species traits over moderate time scales
3. Rapid Evolution and Ecosystem Change
- Evolutionary change can happen quickly—within years or decades—and reshape ecosystems
- Example: Trinidadian guppies evolved under different predation regimes:
- Low predation guppies: feed more on algae → reduced algal biomass
- High predation guppies: feed on invertebrates → increased algal biomass (less invertebrate grazing)
- These behavioral and dietary changes affect primary productivity and community dynamics
4. Reciprocal Feedback Cycle
- Ecological change alters selective pressures, prompting evolutionary responses
- Those evolutionary changes then alter ecological interactions, completing a feedback loop
- This dynamic is captured in eco-evolutionary feedback models
- Example: predator expansion → prey evolves defenses → changes predator-prey interactions
5. Human Impact and Evolution
- Humans can accelerate evolution via actions like overfishing or habitat alteration
- Example: Cod fishing favors early-reproducing, smaller individuals → lowers population recovery potential
- This kind of artificial selection can have lasting ecological impacts
In a Nutshell
Ecological and evolutionary changes are not separate or linear—they continuously influence each other. These eco-evolutionary feedbacks can operate on all time scales, from deep history to a few generations. Understanding this interplay is essential for predicting how ecosystems respond to environmental change, including human activity.