The broad kingdom of Plantae consists of over 2 million different species. These organisms are all non-motile, eukaryotic, multi-cellular, and autotrophic. Their cells contain chlorophyll that helps in photosynthesis. They have various cell organelles for photosynthesis, reproduction, and support.
All of the million species under Kingdom Plantae are classified into five subgroups based on their features, such as their plant body's complexity, presence or absence of a vascular system, and how they bear seeds. These five subgroups are thallophytes, gymnosperms, angiosperms, bryophytes, and pteridophytes.
Thallophyta- They are primitive in terms of body structure and are called 'thallus,' meaning body structure is not well differentiated. They are mostly aquatic (marine or freshwater) or are found in moist habitats. A few examples of Thallophytes are Green algae like Volvox, Spirogyra, and brown algae like Fucus,
Bryophyta- They are a little more complex in terms of body structure when compared with Thallophytes since they have root-like, stem-like and leaf-like structures. They are also terrestrial plants dependent on water for reproduction. It explains why they are called "Amphibians of the Plant kingdom" and why they are mostly seen in moist, shady places. Examples of Bryophytes include Marchantia, Funaria, and Sphagnum.
Pteridophyta- The plants in this subgroup develop distinctly into the root, stems, and leaves. They are terrestrial and have a vascular system within the body, which helps conduct water and minerals to different body structures. They reproduce by dispersing spores and do not produce seeds. Selaginella and Pteris are some common examples.
Gymnosperms- These are further developed plants that are capable of bearing naked seeds. They are fully terrestrial with differentiated body structures. They also have a developed vascular system to supply water and minerals to all these body structures. Pinus, Cycas, and Ephedra are Gymnosperms plants.
Angiosperms- They are the most advanced plants with well-differentiated plant bodies, developed vascular systems, and bear seeds covered within fruits. The significant difference between bryophytes pteridophytes gymnosperms and angiosperms are the seed-bearing capacity. These include plants like Eucalyptus, Rose, Mango, etc.
Differentiate Between Bryophytes and Pteridophytes
There are several similarities between bryophytes and pteridophytes. The alternation of generation in bryophytes and pteridophytes are similar in both. To sum up, the significant difference between Bryophyta and Pteridophyta subgroups are tabulated below.
(Image to be added soon)
Bryophyte Life Cycle
(Image to be added soon)
Pteridophyte Life cycle
(Image to be added soon) (Image to be added soon)
Fun Facts:
Researchers at the University of Exeter discovered that bryophytes might have caused an ice-age during the Late Ordovician Mass Extinction. As they spread across the land, they altered the bedrock composition, sucked in all the air's carbon dioxide, and brought the temperature down.
Bryophytes can absorb water from the air and pass it on to leaves. Since they do not have a vascular system, they do not extract water from the soil through roots like other plants.
Fern species (Pteridophytes) can come in all sizes ranging from 3 inches to even 30 feet tall.
Ferns take up nitrogen from the air, and hence farmers sometimes use ferns as natural fertilizers in rice fields.
In ancient cultures, mosses were used to cleanse and heal wounds. When allied surgeons ran out of cotton on battlefields during World War I, they began to use moss as a temporary stopgap on wounds.
1. Why are Pteridophytes called the “Snakes of the Plant Kingdom”?
Pteridophytes are known as the plant kingdom's Snakes because they are the first type of plants to be entirely terrestrial. In the animal kingdom, reptiles were the first animals to be completely terrestrials. It is by a similar logic that bryophytes are called amphibians of the plant kingdom. They are dependent on both land and water for survival and reproduction.
Like the reptiles, pteridophytes are so widespread that they are the second most diverse subgroup of land plants following angiosperms. There are about 11000 species of pteridophytes in the world. Both Bryophyta and Pteridophyta have a lineage running back to four hundred million years, as suggested by fossil records. There is evidence suggesting that there existed treelike ferns as tall as 36.5 meters, known as Lepidodendron, an ancestor of modern club mosses.
2. What is the ecological significance of Bryophytes?
There are several benefits to the ecosystem due to the widespread growth of bryophytes. Some of them are listed below.
Bryophytes such as mosses and lichens were the first plants to survive on rocks. The acids from the lichens and the dead and decomposing matter from mosses led to soil formation. They are also known as soil binders since they grow densely and prevent soil erosion. Even in case of heavy rains, they reduce the run-off and hold the soil intact.
Further, bryophytes can also create rocks along with algae and calcium bicarbonate. The plants decompose to form bicarbonate ions and precipitate as calcium carbonate. It leads to the formation of calcareous rocks on shallow lakes and a broad mineral deposit area.
Many companies now realize the amount of ocean pollution and ecological damage is due to the excessive use of plastic. Therefore, processed forms of mosses are increasingly used as packing material for fragile items as an eco-friendly alternative.
The peat from which fossil fuels are formed is mostly from decomposed peat moss or Sphagnum. It is also used in the production of ethyl alcohol, paraffin, and dyes.