- Pteridophyta are the first organisms known to have had seeds.
- The heterosporous Selaginella gives credence to this theory.
- Reason is the proper explanation for the assertion that it is correct, thus both it and the assertion are accurate.
- Plants belonging to the genus Selaginella can be either creeping or ascending in their growth habit.
- They have leaves that resemble scales and are simple in appearance.
(a) The capacity or propensity to develop into a seed is referred to as the seed habit. It was formed in fossil gymnosperms of the group Cycadofilicales (pteridosperms), also known as seed ferns, such as Lyginopteris, which possesses characteristics of both ferns and cycads. Seed habit is displayed by a small number of pteridophytes, such as Selaginella, Marselia, Isoetes, and others.
What is the origin of seed habit?
- One of the most significant contributors to the development of terrestrial plants has been the seed.
- A beginning was made in the late Devonian period toward the understanding of the genesis and development of the seed habit.
- It was discovered that the first seed plants or plants with structures similar to seeds existed in the Devonian seed ferns, which belonged to the archetypal pteridosperm genus Lyginopteris.
What are the ancestors of seed-bearing plants?
- Heterospory is a reproductive strategy that has developed on its own in a number of different lineages.
- It is thought to be a step in the process that comes before seed reproduction.
- It is generally agreed that the progymnosperms are the seed plants’ ancestral progenitors.
- b) A wide array of seeds and seed-like structures may be found preserved in the fossils of seed-bearing seed ferns (Lyginopteridopsida).
What was the first seed-like plant on Earth?
It was discovered that the first seed plants or plants with structures similar to seeds existed in the Devonian seed ferns, which belonged to the archetypal pteridosperm genus Lyginopteris. The Pteridosperms are a group of extinct flowering plants that are placed in a transitional position between the Pteridophytes and the seed-bearing plants.
What was the first plant to develop a tree-like habit?
It appears that ferns were the earliest plants to exhibit secondary growth and a woody character. In fact, one species of Wattieza had already reached heights of 8 meters and a tree-like habit as early as the Middle Devonian. It did not take very long for other clades to mature into a tree-like stature.
What is the origin of seed habit?
In the late Devonian period, some 385 million years ago, the beginning of seed colonization and its subsequent development first began to take place. It all started with the emergence of the first modern tree, which was a species of Archaeopteris and created an advanced spore system termed heterospory.
Where is seed habit found?
Pteridophyte plants are characterized by their seed-bearing behavior. There is no evidence of it in any of the lower plants. The pteridophytes are the most sophisticated flowerless and seedless plants in the plant kingdom. It is necessary to be aware of the fact that they make up the biggest living group of primitive vascular plants.
What is seed habit example?
The preservation and germination of a single megaspore within a megasporangium is referred to as the seed habit. This is an adaption of the heterospory reproductive strategy. It is often regarded as the most sophisticated and fruitful technique of sexual reproduction, which is utilized by the majority of terrestrial plant species.
What is seed habit in gymnosperm?
- The Devonian period saw the first appearance of these plants, and by the Carboniferous period, they had become commonplace.
- In appearance, seed ferns were similar to some progymnosperms in that they were tiny trees with fernlike leaves (the equivalence of a progymnospermous flattened branch) that bore seeds.
- Seed ferns were also similar to progymnosperms in that they were classified as gymnosperms.
What is seed habit in plants?
- The seed habit is the mode of sexual reproduction in vascular land plants that is the most complicated and diversified of all the possible modes.
- Since their first appearance in the Late Devonian, seed plants have evolved to dominate practically every terrestrial ecosystem.
- This trend began with their ability to reproduce sexually and produce seeds.
- They also cover a wider range of habitats than any other group of Tracheophytes, which makes them very diverse.
Can origin of seed habit be traced in pteridophytes?
The origin of seed habitat may be traced back to pteridophytes, which is the solution. Some pteridophytes, such as Selaginella and Salvinia, are heterosporous, meaning that they generate two different kinds of spores: microspores (which are very small) and macrospores (which are very large). When these spores germinate, they create male and female gametophytes, respectively.
Is pteridophytes precursor of seed habit?
- Pteridophytes are known for their habit of producing seeds, which is seen as an important evolutionary step due to the reasons given above.
- Explanation: There are a few genera of pteridophytes that exhibit heterospory, such as Selaginella and Salvinia.
- Heterospory is regarded to be a forerunner to the seed habit.
- They generate both microspores and megaspores as a byproduct of their reproductive process.
What is Pteridophyte Apogamy?
Apogamy refers to the process in which sporophytes are developed directly from gametophytes without the involvement of syngamy or sexual fusion. It is a widespread and common process that can be noticed in ferns that the sporophytes have some haploid chromosome numbers, similar to those seen in the gametophytes.
What is seed habitat?
- The phenomenon known as ″seed habit″ is something that emerged as a result of the spermatophytes’ adoption of heterospory, which is the retention and germination of a single megaspore within a megasporangium in order to form a female gametophyte.
- This is a distinguishing feature of the spermatophytes.
- An embryo that was created as a consequence of fertilization is contained within an ovule, which is what we refer to as a seed.
What is heterospory in Selaginella?
- The trait known as heterospory is associated with Selaginella.
- Both microspores and megaspores are created by this plant.
- Microspores are produced in the plant’s microsporangia, while megaspores are produced in the plant’s megasporangia.
- Microspores are responsible for the production of male gametophytes, whereas megaspores are responsible for the production of female gametophytes.
- The presence of heterospory is necessary for normal seed development.
What is the difference between pteridophytes and gymnosperms?
There is no seed present in pteridophytes, whereas gymnosperms are classified as spermatophytes (seed plants).
What is the habitat of pteridophytes?
Pteridophytes can be found in environments that are wet, gloomy, and damp. They live in the cracks and crevices of rocks, as well as in tropical trees in bogs and swamps.
What is seed habit BYJU’s?
The phenomena known as ″seed habit″ was caused by the preservation of a single megaspore within a megasporangium, the adoption of heterospory, and the germination of that megaspore in order to generate a female gametophyte. It is an attribute that is unique to the spermatophytes as a whole. An embryo, food reserves, and a seed coat are the three components that make up a seed.