It is speculated that life began in the oceans, and through millions of years of evolution, life slowly adapted on to dry land. Problems of cytology and evolution in the pteridophyta by manton, i. Between the fossil gymnosperms and the present forms there has occurred a reduction of the antheridial jacket and the corresponding production of a. Characteristics of pteridophytes, morphology of pteridophytes, reproduction of pteridophytes, homosporous and heterosporous pteridophytes, megaspore and microspores, gametophytes of pteridophytes, fertilization, zygote and embryo of pteridophytes, life cycle. In this article, we also provide complete details of the b. Pteridophytes or pteridophyta, in the broad interpretation of the term or sensu. Types of stelar systems and its evolution in pteridophytes.
Why are pteridophytes better adapted to dry land than bryophytes. Taxonomy and biogeography of indian pteridophytes springerlink. At first you see forms vaguely resembling ferns and bit by bit the image becomes sharper. Economic importance of pteridophytes,several ferns such as angiopteris, asplenium, marattia, microsorium, nephrolepis, phymatodes, etc. Pteridophytes are a vascular plant and since bryophytes have no vascular system they are not capable to transport the water and nutrients from one part of the plant to another but pteridophytes can. They formed the dominant part of the earths during palaeozoic and mesozoic periods on soral evolution. In both pteridophytes and gymnosperms, the general structure of the archegonium is almost similar. Energy healthy bacteria bacterial resistance and evolution gram staining alternations of generations bryophytes, pteridophytes, gymnosperms, angiosperms plant organization the amazing plant race phylum porifera. In lastrea pseudomas polydactyla wills, the authors still maintain their claim, made in a preliminary paper, that there is a migration and fusion of prothallial nuclei. A similarity exists between these gymnospermous systems and the parastichous type.
They formed the dominant part of the earths during palaeozoic and mesozoic periods. Were pteridophytes always less abundant than phanerogamic plants. Classification of pteridophytes for a long time the division pteridophyta includedthe ferns, lycopods and horsetails. The two main vascular elements are the xylem and phloem. Occurrence and evolution of pteridophytes pteridophyta is a group of ancient plants. We now turn to a consideration of the vascular system of the modern ferns, and in tracing its various modifications. Pteridophytes do not have seeds or flowers either, instead they also reproduce via spores. A field manual of the ferns and fernallies of the united state and. A few pteridophytes are aquatic while still others are epiphytes. This pdf version does not have an isbn or issn and is not therefore effectively. Seeds, pollen, and wood in the long evolutionary history of plants, few developments have had more profound consequences than the evolution of seeds and pollen. Reduction in the number of vegetative prothallial cells appears to have occurred early in gymnosperm evolution, so that the male gametophyte may be regarded essentially as a reduced antheridium. Ferns, horsetails often treated as ferns, and lycophytes clubmosses, spikemosses, and quillworts are all pteridophytes.
Sumita, assistant professor, department of botany, pggc11, chandigarh. Seed bearing plants have been prominent in nearly all terrestrial ecosystems from the paleozoic era to today. The evolution of a resistant cuticle, complex stomata, vascular tissue, and lignin enabled. In general, pteridophytes have a long fossil record and. Both these pteridophytes have completely endosporic male gametophytes with one prothallial cell and an antheridium with 256 antheriozoids in selaginella and only four in isoetes. The first vascular plants rapidly diversified to cover the earth. The moderff ferns and anatomical evolution the hymbnophyllaceig. Pteridophytes ferns and fern allies the plant list. Sc notes pdf download all semester notes latestnews24. Already on the origin of plant lineage, we still have no safe dating for the endosymbiotic event, i. Occasionally the term is also used to describe the young gametophyte of a liverwort or peat moss as well the prothallus develops from a germinating spore. Pteridophytes general characters ppt general characteristics, life cycle and reproduction of pteridophytes ppt what are pteridophytes.
Problems of cytology and evolution in the pteridophyta by. Pteridophytes ferns chapter pdf available february 2003. Tansley lecturer on plant anatomy at university college, london. The three groups of bryophytes are morphologically distinct from one anoth er chopra 1968, but it is rarely recog nized that such distinctions are due to fundamental differences in morpho genetic design. All pteridophytes have a true alternation of generations, in which a dominant sporophyte generation produces spores through meiosis, and a freeliving gametophyte generation forms gametes egg and sperm by mitosis. Publication date 1950 topics pteridophyta, karyokinesis publisher.
Pteridophytes introduction, authors and addresses, systematic list, glossary, and key to tribes. Occurrence and evolution of pteridophytes biology boom. Comparative habitat requirements for spore germination and prothallial. In 1880, the cryptogams of the plant kingdom were divided. Please wash your hands and practise social distancing. All these very large evolutionary jumps are discussed on the basis of the phyletic gradualist neodarwinian theory and other genetic evolutionary mechanisms. The primary components of stele are xylem and phloem. Full text of the origin of gymnosperms and the seed habit. This pdf version does not have an isbn or issn and is not therefore effectively published melbourne code, art.
Phytochemical studies in pteridophytes growing in brazil. Pteridophyta in the broad interpretation of the term are. The following separation of the main growth forms of pteridophyta is proposed. Most of the pteridophytes ferns and fernallies show their luxuriant and vigorous growth during the rainy season particularly in the hilly regions usually above 1400 m altitude. Firstly all the botanists divided the plant kingdom into two large groups cryptogamia and phanerogamia, linnaeus 1754 used the term cryptogams for the first time for those plants which did not possess visible sex organs. The influence of soil evolution on pteridophyte diversification. Stelar theory also says that the cortex and the stele are the two fundamental. And among the first of the plants to truly live on land were the pteridophytes.
In some forms, as the abietineae, the development of two or three prothallial cells, distinct from the large antheridial cell, is a wellknown fact, an amount of prothallial develop ment not shown by any other living heterosporous forms, even the heterosporous pteridophytes. The simpler terms open and closed dormer, 1945, 1946a are preferable since sympodia are of course the essential longitudinal components of both systems esau, 1965, p. Molecular evolution of pteridophytes and their relationship to seed plants. During the past two decades, the discoveryof fossil spores from as far back as the midordovician. Primitive siphonostele protostele with central pith. Tissues like pericycle, medullary rays and pith are also the components of stele. Pteridophytes or pteridophyta, in the broad interpretation of the term, are vascular plants plants with xylem and phloem that reproduce and disperse via spores. Pteridophyta is the most highly evolved group among the cryptogams. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
The origin and early diversification of land plants marks an interval. With the commencement of monsoon about mid june, the ferns and fernallies start growing vigourously and luxuriantly. The printed version, however, was effectively published on 6 june 20. Occurrence and evolution of pteridophytes with its origin and economic importance in pteridophyta is a group of ancient plants. Or the sporangia usually occur in clusters called sori or sorus,found on the underside fertile leaves.
Polyploidy occurs in the heterosporous and homosporous pteridophyta, but with a much higher frequency in the latter. Evolutionary significance of polyploidy in the pteridophyta. Liebig 1931 pointed out a sort of similarity between the male gametophytes of isoetes and some fossil gametophytes like cordainthus. Pteridophytes constitute a significant and important group in the plant kingdom. Missouri botanical garden and washington university. On the basis of their anatomy jeffrey in 1902 divided the vascular plants into two types or stocks. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as cryptogams, meaning that their means of reproduction is hidden.
All the pteridophytes possess a vasculature in the center of the axis traversing from one and to the other and branching with all the branches. Thus, these characteristics make them horticulturally important plants. Sachs 1868 for the first time classified pteridophytes according to the type of spores. Types of stelar systems and its evolution in pteridophytes and higher plants with ppt. Future studies may attempt to compare this oceanic archipelago with other islands that are rich in pteridophyte diversity, such as the mascarene islands hennequin et al. Reproductive biology and evolution in the pteridophyta. Pteridophytes biology encyclopedia plant, body, different. There are five types of protostele in pteridophytes they are 1. A field manual of the ferns and fernallies of the united states and. Each of these can be divided into life forms according to a series of morphological and other characters. Lloyd in flowering plants many of the diverse characteristics utilized in systematics to determine phylogenetic relationships represent direct adaptations to specific methods of pollination or reproduction. The biosystematics of pteridophytes iowa state university digital.
Apogamy and apospory in ferns university of chicago press. Unlike the bryophytes, these plants are in the mainstream of land plant evolution and eventually gave rise to the seed plants. By assembling and analyzing the most inclusive molecular dataset for leptosporangiate ferns to date, i provide unprecedented insight into overall fern. Some of the species belonging to this division have small leaves called as the microphylls. Useful notes on the classification of pteridophytes. A concept based exclusive material pteridophytes, gymnosperms. Most pteridophytes are terrestrial plants and thrive well in abundant moisture and shade while some flourish well in open, dry situations especially in xeric conditions. There are two theories regarding evolution of bryophytes. Stelar evolution in pteridophytes ppt types of steles and its evolution in pteridophytes ppt what is stele. They are the vascular plants those having xylem and phloem tissues that reproduce by releasing spores rather than seeds, and they include the highly diverse true ferns and other graceful, primarily forestdwelling plants. A prothallium, or prothallus from latin pro forwards and greek thallos twig is usually the gametophyte stage in the life of a fern or other pteridophyte.
The sporophyte was the dominant phase of the life cycle of these early pteridophytes. Pteridophytes pteridophtyes are a phylum of plants. Evolution of bryophytes according to these theories the evolution in bryophytes is as follows. Accordingly several major groups of vascular plants, many minor groups and a large number of genera have had to be omitted. Ferns can be used to illustrate the life cycle stages common to all pteridophytes. The plant body can be divided into a true root, stem, and leaves. The stele is a real entity and present universally in all axis of higher plants.
What is one evolutionary advantage pteridophytes have over. The modern classification of pteridophytes have been suggested by many scientist according to the sporne1975 pteridophytes have been classified into six classes. What is one evolutionary advantage pteridophytes have over bryophytes. The pteridophytes occupy the intermediate position in between the bryophytes on one hand and the phanerogams on the other.
As they produce neither flowers nor seeds, they are referred to as cryptogams. I the emergence of ferns is best to be compared with a looming up from the fog. The pteridophytes are an economically important group of plants. A prothallus, or prothallium, from latin pro forwards and greek thallos twig is usually the gametophyte stage in the life of a fern or other pteridophyte. Ninetysix percent of the homosporous pteridophyta show a gametic chromosome number greater than 27, whereas 90 percent of the heterosporous ones possess a gametic chromosome number less than 28. Sc is usually divided into 3 years or 2 semesters in each years total of 6 semesters. They are preserved in the form of fossils or coal deposits.
In a book of this limited size it is impossible to describe in detail all the fossil plants that are known. Even today, many tribal communities and rural populations are dependent heavily upon the natural resources obtained from the surrounding forest regions for treatment of various ailments and diseases. A pteridophyte is a vascular plant with xylem and phloem that disperses spores. Although bryophytes and pteridophytes have gametes tha depend on water for fertilization, the emergence of conducting vessels in this last group facilitated life in a terrestrial environment. Bryophytes, pteridophytes, gymnosperms, angiosperms pages. The most characteristic feature of the pteridophytes is the presence. Nayar and his collaborators, pertaining mainly to taxonomy of indian pteridophytes, is presented, including his philosophy on phylogeny and evolution and the phyllorhize theory, which seeks to replace the axial theory and stelar theory. Sphenophyta, pterophyta from biol 9 at the university of hong kong. Pteridophyta characteristics, life cycle, classification.
However, additional phylogenetic dilemmas are the evolution of bryophytes from algae and the transition from these first land plants to the pteridophytes. It is a shortlived and inconspicuous heartshaped structure. Stelar theory, components of stele, different types of steles in plants, protostele. Read the introductory remarks and list of characteristics of the bryophytes p. Pdf molecular evolution of pteridophytes and their. They are psilopsida, psilotopsida, lycopsida, sphenopsida, pteropsida and progymnospermopsida. There are also some purely aquatic ferns such as water fern or water velvet salvinia molesta and mosquito ferns azolla species. Types of stele and its evolution in pteridophytes vivek roys.
Pdf the fern gametophyte has interested plant biologists for the past. Write an essay on stelar evolution in pteridophytes with suitable examples and neat diagrams. Types of stele and its evolution in pteridophytes youtube. In lower pteridophytes, the prothallial cells which enclose the venter.
The same organization occurs in endosporal gametophytes of lower tracheophyta of the present day. The different species of selaginella are grown as the garden plants. The pteridophytes are the successful colonisers on land habit. Although the evolution of these pathways is poorly understood, possible phenolic precursors have been detected in charophycean algae4,31, and elements of auxin metabolism have been recognized in mosses and hornworts49. Fre 1852 was the first pteridologist to introduce characters of the spore as a criterion in the taxonomy and classification of ferns. Life forms of pteridophyta, their origin and evolution. The xylem consists of mostly, tracheitis and rarely, vessels selaginella, pteris etc. They possess certain combinations of major characters which are not found in bryophytes or in phanerogams. Basic types of steles protostele central xylem, surrounding phloem. Many aspects of difficult interpretation exist in the phylogenetic history of land plants. View the article pdf and any associated supplements and figures for a period of 48 hours. The kingdoms monera, protoctista and fungi biology module 1 diversity and evolution of life 30 notes 2.
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