Plant evolution — key innovation behind angiosperm dominance Considering major plant groups, which single feature is most often credited with the evolutionary success and ecological dominance of angiosperms (flowering plants)?

Introduction / Context:
Angiosperms (flowering plants) dominate most terrestrial ecosystems. While they possess multiple adaptive traits, biologists frequently highlight one innovation as pivotal for their diversification and reproductive success: flowers. This question asks you to identify that single most influential feature.

Given Data / Assumptions:

• Group in focus: angiosperms.
• Objective: identify the primary innovation linked to their success.
• Constraints: select one best answer among several attractive plant traits.

Concept / Approach:

Flowers are complex reproductive structures that enable precise pollen transfer (often animal-mediated), specialized reproductive timing, and high-efficiency fertilization. Coevolution with pollinators (insects, birds, bats) increased outcrossing and speciation rates. While seeds and fruits also matter, gymnosperms also have seeds; thus seeds alone cannot explain angiosperm dominance. Fruits aid seed dispersal, but they function downstream of successful pollination and fertilization, which flowers facilitate.

Step-by-Step Solution:

Verification / Alternative check:

Comparative botany and macroevolution studies consistently connect the radiation of angiosperms with the emergence of flowers and associated pollination syndromes.

Why Other Options Are Wrong:

Seeds: also present in gymnosperms; not unique. Fruit: important but derivative of successful flowering. Broad leaves: many plants have them; not decisive. Vascular tissue only: predates angiosperms (ferns and gymnosperms).

Common Pitfalls:

Equating “seeds” with angiosperm success and forgetting gymnosperms. Ignoring coevolution with pollinators as the main driver.

Final Answer:

Flowers