The evolution of hummingbirds' beaks and plants with deep tubes in their flowers is an example of:

• A. genetic drift
• B. convergent evolution
• C. co-evolution
• D. artificial selection

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by understanding the concept of co-evolution. Co-evolution occurs when two or more species influence each other's evolutionary trajectory due to close ecological interactions. In this case, hummingbirds and plants with deep tubular flowers are examples of species that have evolved traits in response to each other.
2. Step 2: Analyze the relationship between hummingbirds and plants with deep tubular flowers. Hummingbirds have evolved long, specialized beaks that allow them to access nectar deep within the flowers, while the plants have evolved deep tubes to ensure that only specific pollinators, like hummingbirds, can access their nectar, promoting effective pollination.
3. Step 3: Compare co-evolution with other evolutionary concepts mentioned in the problem. Genetic drift refers to random changes in allele frequencies in a population, which is unrelated to the mutual adaptation seen in co-evolution. Convergent evolution refers to unrelated species developing similar traits due to similar environmental pressures, which is not the case here. Artificial selection involves human intervention in breeding, which is also not applicable.
4. Step 4: Recognize that the mutual adaptation between hummingbirds and plants with deep tubular flowers is a clear example of co-evolution, as both species have evolved traits that benefit their interaction and survival.
5. Step 5: Conclude that the correct answer is co-evolution, as it best describes the evolutionary relationship between hummingbirds and plants with deep tubular flowers.