Concept 52.5 — Ecological change and evolution

Ecological change and evolution (Concept 52.5)

• Core idea: Ecological interactions can cause evolutionary change, and evolutionary change can alter ecological interactions; they influence one another over both short and long timescales.
• Long-term eco-evolutionary linkages (millions of years):
  • Origin and diversification of plants altered carbon cycling, removing CO₂ from the atmosphere.
  • New plant species created new habitats and food sources for insects and animals, triggering bursts of animal speciation.
  • Ecological changes and evolutionary changes exert reciprocal, ongoing effects over deep time.
• Short-term and mid-term linkages (years to decades):
  • Ecological change can drive rapid evolutionary change (e.g., soapberry bug beak-length changes; formation of new sunflower species).
  • Rapid evolution can drive ecological change (e.g., Trinidadian guppies). When predators are removed:
  • Guppy populations evolve larger body sizes and change color patterns; they produce fewer but larger offspring.
  • Larger guppies excrete more nitrogen, altering nutrient availability in streams and boosting primary producers like algae.
  • These ecological changes feed back to evolutionary pressures, creating rapid eco-evolutionary feedbacks.
• Implications for prediction and management:
  • Human actions or other environmental changes can trigger complex feedbacks between ecology and evolution.
  • Predictive models should account for potential reciprocal effects across multiple timescales.
• Figure references (conceptual):
  • Figure 52.22 illustrates reciprocal eco-evolutionary effects between ecological change and evolution.
  • Figure 52.23 shows how evolved body size in guppies affects nitrogen excretion and ecosystem dynamics.
• Concept Check 52.5:
  1. Describe a scenario showing how ecological change and evolution can affect one another.
  2. MAKE CONNECTIONS: Commercial fisheries target older, larger cod fish, causing cod that reproduce at a younger age and smaller size to be favored by natural selection. Younger, smaller cod have fewer offspring than do older, larger cod. Predict how evolution in response to fishing would affect the ability of a cod population to recover from overfishing. What other reciprocal eco-evolutionary effects might occur? (See Concept 23.3.)
• Summary takeaway: Ecological changes and evolutionary changes are interconnected processes that can potentiate rapid feedback loops across diverse timescales, influencing ecosystem structure and function.