Final answer:
Plant evolution is marked by several key innovations, including the development of vascular tissues, seeds, cuticle and stomata for water retention, leaves for improved photosynthesis, and the evolution of flowering plants with fruits.
Step-by-step explanation:
The key evolutionary innovations of plants include the evolution from an aquatic ancestor to various adaptations that enabled them to thrive on land. Initially, plants like nonvascular plants emerged without vascular tissues. However, as evolutionary pressures demanded, plants developed vascular tissues to support their structure and facilitate efficient transport of water and nutrients. Another pivotal innovation was the formation of seeds, which allowed plant embryos to be protected and nutrients to be stored, aiding in the successful reproduction on land without moisture.
As plants continued to evolve, some developed a cuticle to minimize water loss, as well as stomata for gas exchange. The emergence of leaves improved photosynthesis by increasing surface area for light absorption. Successively, adaptations such as the wood-forming lignin, and roots for anchorage and nutrient acquisition, allowed plants to grow taller and larger. This evolutionary trajectory culminated in the appearance of flowering plants, which formed flowers and fruits, significantly enhancing their reproductive success and seed dispersal.