What characteristics allowed plants to succeed in a terrestrial environment? What characteristics allowed them to spread to a wide variety of habitats?
Plants evolved from aquatic organisms called algae. To survive in terrestrial environments, they had to develop methods of fighting desiccation and gravity. Land plants were able to do this through adaptations that protected their gametes, that protected their body and embryo, and that provided structural support.
Gamete protection was achieved by the development of multicellular gametangia, or structures responsible for producing gametes. Fertilization then occurs within this multicellular structure, which provides embryotic protection. Structural support was achieved by the development of a cell wall made of cellulose. The rigidity of this wall is essential to land plants’ ability to withstand gravitational pressure.
Later, the development of vascular tissue and roots allowed plants to grow taller and to thrive in areas with less moisture. Water could be absorbed from the soil and then transported to other places within the plant. This reduced the threat of desiccation and reduced the impact of gravity, allowing land plants to spread to a variety of environments.