Plant evolution refers to the gradual changes in plant species over millions of years, driven by environmental factors and genetic variations. It began with simple, single-celled organisms in water, which eventually evolved into more complex forms. Key milestones include the development of mosses, ferns, and flowering plants, each adapting to different habitats and climates. The transition from water to land was significant, leading to the evolution of structures like roots, stems, and leaves. These adaptations allowed plants to absorb nutrients, support themselves, and perform photosynthesis efficiently. Today, plants play a crucial role in ecosystems, providing oxygen and food for various organisms.