The information below was adapted from OpenStax Biology The ancestor of all land plants was an aquatic, green algal-like species. Living in the water provides a number of advantages compared to life on land:. If life on land presents so many challenges, why did any land plants evolve to live on land?
The transition from an aquatic to a terrestrial environment occurred as a result of a number of specific adaptations to the above challenges to survival on land. In fact, modern land plants have an array of adaptations to life on land, but they did not evolve all at once. In addition, different adaptations are present in different plant lineages. The adaptations and characteristics which ARE present in nearly all land plants include :. Early land plants could not live very far from an abundant source of water.
Over evolutionary time, land plants evolved strategies to survive in increasing degrees of dryness:. The phylogenetic tree below shows the evolutionary relationships between modern plants, as well as the origins of adaptations in each plant lineage:.
Usually one of these stages is large and multicellular the organism we can see by eye , while the other is small and unicellular. The gametophyte gives rise to the gametes reproductive cells by mitosis.
This can be the most obvious phase of the life cycle of the plant, as in the mosses, or it can occur in a microscopic structure, such as a pollen grain, in the v ascular plants.
The sporophyte stage is barely noticeable in nonvascular plants. Towering trees are the diplontic phase in the lifecycles of plants such as sequoias and pines. The image below shows a simplified version of the alternation of generations life cycle:. Though all plants display an alternation of generations life cycle, there are significant variations in different lineages of plants, consistent with their evolutionary history and order of origination:.
The video below describes the features of nonvascular plants mosses, liverworts, hornworts , and their alternation of generations life cycle:. The video below describes the features of vascular plants and their alternation of generations life cycle:.
The early era, known as the Paleozoic, is divided into six periods. The major event to mark the Ordovician , more than million years ago, was the colonization of land by the ancestors of modern land plants. Fossilized cells, cuticles, and spores of early land plants have been dated as far back as the Ordovician period in the early Paleozoic era. These earliest plants to colonize land would have been nonvascular plants, lacking true leaves or roots and living in extremely damp environments close to water.
The oldest-known vascular plants have been identified in deposits from the Devonian. These now-extinct vascular plants probably lacked true leaves and roots and formed low vegetation mats similar in size to modern-day mosses, although fossils indicate that some reached up to one meter in height.
Fossil evidence indicates that, by the end of the Devonian period, ferns, horsetails, and seed plants populated the landscape, giving rise to trees and forests throughout the Carboniferous. The club mosses and other seedless vascular plants dominated the landscape of the Carboniferous, growing into tall trees and forming large swamp forests alongside horsetails—some specimens reaching heights of more than 30 m ft —covering most of the land.
These forests gave rise to the extensive coal deposits that gave the Carboniferous its name. The video below describes the impact and legacy of vegetation during Carboniferous period:. The vegetation covering the Earth in the Devonian and Carboniferous periods helped enrich the atmosphere in oxygen, making it easier for air-breathing animals to colonize dry land.
Plants also established early symbiotic relationships with fungi, creating mycorrhizae. In the mycorrhizal relationship, the fungal network of filaments increases the efficiency of the plant root system, and the plants provide the fungi with byproducts of photosynthesis. Gymnosperms, the earliest seed plants, also first appeared in the fossil record during the Devonian. Seedless vascular plants had previously colonized land, and the wet Devonian climate allowed the seedless plants to proliferate quickly.
However, the Permian period at the end of the Paleozoic era saw much drier climates, and the dry climate provided gymnosperms an advantage over seedless plants because plants with seeds are better able to survive dry periods due to reproduction with pollen and seeds.
Gymnosperms expanded in the Mesozoic era about million years ago , supplanting ferns in the landscape, and reaching their greatest diversity during this time. The Jurassic period of the Mesozoic era was as much the age of the cycads palm-tree-like gymnosperms as the age of the dinosaurs. Angiosperms flowering plants are the most recent lineage of land plants to evolve. What are the three adaptations of plants needed to survive on land? What adaptation allowed plants to live on land? What was a prerequisite for the survival of life on land?
What are three evolutionary innovations that improved the probability of survival on land among How did plants first move from the oceans to land? See all questions in Survival on Land. Impact of this question views around the world. Abstract The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats.
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