Seedless plants were the first to appear on the barren rocky landmass of the earth as in the form of cyanobacteria and later on developed and multiplied and spread and dispersed to the formation of various ecosystems biomes and habitats on earth.
Plants like ferns and horsetails are considered to the first to originate on the planet at the Devonian period of dinosaurs and these plants, later on, acquired the properties to bear seeds like the angiosperms and gymnosperms.
As these primitive plants were adapted to live in aquatic habitats they used to live damp and shady places and later on mature and developed properties of life in terrestrial habitats an example of Ricca being a primitive plant adapted to the water and could sustain itself by the diffusion of water in and out.
Superposition and geologic timescale support the theory because of the changes in features in index fossils of diverse periods are presumed to be caused by evolution, and the existence of different organisms in different periods is then used to support biological evolution.
