For many years it has been generally assumed by botanists that in angiosperms, as in the heterosporous pteridophytes, the megaspores are larger than the microspores. The adoption of heterospory and the retention and germination of a single megaspore within megasporangium to form a female gametophyte, led to the. In some species of homosporous ferns, gametophytes. Cyanobacteria are classified under a protista b plantae c monera d algae. The condition of production of two different types of spores in the same species is known as the heterospory. Pteridophyta general characteristics, classification and stelar system pteridophyta are the most primitive vascular plants.
It is pretty generally recognized that there is no true epi dermis in pteridophytes. Seed is the ripened ovule with integuments formed after fertilization. The sexuality of pteridophytic gametophytes can be classified as follows. Heterospory evolved first in pteridophytes such as selaginella and salvinia. When such attempts lime been made the definitions show striking contrasts in content and or emphasis table i. An introduction to pteridophyta start download portable document format pdf and ebooks electronic books. An introduction to pteridophyta top results of your surfing an introduction to pteridophyta start download portable document format pdf and ebooks electronic books free online rating news 20162017 is books that can provide inspiration, insight, knowledge to the reader. Heterospory means production of two different sizes of sporesmegaspore and microspore. They are known as megasporangium ovule and microsporangium. This fossil history and the fact that isoetes and the heterosporous water ferns are aquatic. For many years it has been generally assumed by botanists that in angiosperms, as in the heterosporous pteridophytes, the megaspores are.
Importance of heterospory and seed habit of ferns 581 words abstract the evolution of the seed is one of the major events in the history selaginlela land plants. Most of the pteridophytes are homosporous, produce isospores. Pteridophytes constitute a significant and important group in the plant kingdom. The evolution of the seed habit is related to the retention of the megaspore. Heterospory and seed habitat origin of seeds and seed habitat in vascular plants from heterospory heterospory is the production of two or more types of spores. Cyanobacteria are classified under kingdom monera as they are prokaryotes. Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants. Pteridophyta characteristics, life cycle, classification.
The microsporangia contain microspores whereas megasporangia contain megaspores in them. A seed ovule may be defined as an integumented indehiscent megasporangium. The heterosporous pteridophytes show certain characteristics, which are precursor to the seed habit in gymnosperms. Heterospory and seed habit in pteridophytes botany.
Some pteridophytes are aquatic and some are epiphytes. Here we have given ncert exemplar class 11 biology chapter 3 plant kingdom. In both types, the gametophyte obtains the nutrition from the sporophyte. A gametophyte free living structure formed in pteridophytes. Difference between homosporous and heterosporous pteridophytes. The condition of heterospory in selaginells constitute one of the very important phases in the evolution of the plants. In seed plants, two types of sporangia develop on sporophylls. Some of the characters of pteridophytes are as follows. Pdf summary the origin of the seedplant life history, and subsequent. This document is highly rated by neet students and has been viewed 388 times. Heterospory is thus considered an important step in evolution as it is a precursor to the seed habit. The smaller of these, the microspore, is male and the larger megaspore is female. In homosporous pteridophytes, the sex differentiation takes place only during the development of antheridia or archegonia.
There is further elaboration of the megasporangium so as to enable it to be an ideal starting point for the development of a new plant. A sporophytic free living structure formed in pteridophytes. In most of the heterosporous plants, the gametophyte is restricted to very few cells. Free online biology multiple choice quizzes and practice tests for 5th grade, 7th grade quiz, igscse quiz, ap biology quiz, sat biology quiz, neet mcq, class 10 and 12 and all biology exams.
The adoption of heterospory and the retention and germination of a single megaspore within megasporangium to form a female gametophyte, led to the phenomenon of seed habit, a characteristic feature of the spermatophytes. Most of the pteridophytes produce one kind of similar spore. In selaginella, nutritive tissue called tapetum is present. Download offline apps based on latest ncert books 202021 for new session. Being the first successful colonisers in land habit pteridophytes show both the homospory and heterospory. Full text of the origin of gymnosperms and the seed habit. The existence of heterospory has importance in the origin and evolution of seed. The microspores produce male gametophyte which produces male gametes, while the megaspores produce female gametophyte which produces archegonia and provides nourishment to the embryo. Importance of heterospory and seed habit of ferns 581 words.
Jason stephenson sleep meditation music 9,703,915 views. Each microsporangium contains a large number of microspores whereas each megasporangium contains usually only. Thus the origin of the seed habit is a logical progression that began with homospory, was followed by stages of heterospory, and culminated into the seed. Relaxing rain and thunder sounds, fall asleep faster, beat insomnia, sleep music, relaxation sounds duration. Heterospory is production of diploid and tetraploid spores sexual and asexual spores large and small spores haploid and diploid spores. Ncert solutions 202021 are updated according to new cbse syllabus 202021 to all boards who are using ncert books. Multiple choice quiz on pteridophytes biology multiple choice quizzes. Retention of the female gametophyte within the megasporangium on the parent plant for proper parental care of new embryo. In majority of the pteridophytes all the spores are of similar kinds, such plants are called homosporous.
Ebook an introduction to pteridophyta as pdf download. Multiple choice quiz on pteridophytes biology multiple. To watch the full class on pteridophytes and gymnosperms for your neet exam for free, click. Finally, we deal with the phylogeny of homoiohydry and the seed habit to see if the deliberations on the minimum size of seeds and of homoiohydric seedlings can shed any light on the ecophysiological performance of young sporophytes of homosporous and heterosporous pteridophytes.
Class 11 important questions for biology plant kindom. Therefore, integuments cannot explain the evolutionary success of seed plants. Heterospory the sporangia show greater specialization that those of ferns. Alternative views of character state distributions in the evolution of. In general terms, the relatively derived seed plant lineages. To watch the full class on pteridophytes and gymnosperms for your neet exam for free, click here. Thus, heterospory leads to a reduction of the gametophyte. We highlight a positive correlation between a coenocytic growth phase and increased ovuleseed size in early spermatophytes. Heterospory and seed habit are often exhibited by a plant possessing a petiole b ligule c bract d spathe. Jul 17, 2019 anybody can ask a question anybody can answer the best answers are voted up and rise to the top. Ncert exemplar class 11 biology chapter 3 plant kingdom multiple choice questions q1. Most pteridophytes are terrestrial and grow in moist and shady places while some flourish well in open, dry places especially in xeric conditions. The retention of megaspores and the dispersal of microspores allow for both dispersal and establishment reproductive strategies.
The spores are differentiated into microspores and megaspores borne on the microsporangium and megasporangium. Apr 25, 2020 notes edurev is made by best teachers of neet. Students can download bio botany chapter 2 plant kingdom questions and answers, notes pdf, samacheer kalvi 11th bio botany book solutions guide pdf helps you to revise the complete tamilnadu state board new syllabus and score more marks in your examinations. Jul 20, 2019 importance of heterospory and seed habit of ferns 581 words abstract the evolution of the seed is one of the major events in the history selaginlela land plants. What is the difference between homosporous and heterosporous pteridophytes. University botanyi is a comprehensive textbook for students of 1st year b.
Evolution of seed habit in selaginella pdf pdf summary the origin of the seedplant life history, and subsequent should be considered two independent, fundamentally distinct evolutionary. What are the similarities between homosporous and heterosporous pteridophytes. Heterospory evolved during the devonian period from isospory independently in several plant groups. Heterospory produced the first endosporic inside the spore wall type of gametophyte development in land plants. Every care has been taken to present the subject in a simple language and in a profusely illustrated manner for better understanding. Heterospory and seed habitat in pteridophytes easybiologyclass. Samacheer kalvi 11th bio botany solutions chapter 2 plant.
Alpmt 2015, cancelled a chlorella and spirulina are used as space food. The book also discusses topics like heterospory, seed habit, leaf phylogeny, stellar system, alternation of generations, regeneration in general and special role of germ cellsegg and sporein life cycle. Heterospory advanced to the seed habitat in land plants. It is characterized by morphologically dissimilar spores produced from two types of sporangia. They are differentiated into micro and megasporangia. Neet aipmt biology chapter wise solutions plant kingdom. Heterospory and seed habit in pteridophytes ferns evolution of the seed is one of the most crucial adaptations in phanerogams for successful survival in terrestrial habitat. A seed is that ovule which contains an embryo developed as a result of fertilization. Evolution of the seed habit consists of at least two independent problems.
How far does selaginella one of the few living members of lycopodiales pteridophytes fall. Ncert exemplar class 11 biology chapter 3 plant kingdom are part of ncert exemplar class 11 biology. Nonetheless, dioicy can undoubtedly occur in homosporous pteridophytes. The minimum size of seeds and spores in relation to the.
Heterospory is a condition of the production of more than one type usually two of spores in a single plant. The most successful origin of heterospory ultimately resulted in the great diversity of seed plants. Such peridophytes are known as homosporous and this phenomenon is known as homospory. Heterospory and the origin of the seed habit deepdyve. Pteridophyta general characteristics, classification and. This adaptive ability of heterospory increases reproductive success as any type of environment favors having these two strategies. Heterospory was a key event in the evolution of both fossil and surviving plants. Types of stele and its evolution in pteridophytes duration. Apr 25, 2020 heterospory and origin and evolution of seed habitat in land plants pteridophytes. The book is written strictly in accordance with the revised common core syllabus adopted by the universities in andhra pradesh. These plants posses some of the characteristics which are precursors of the seed habit and these are. Seed habit originated in algae fungi bryophytes pteridophytes. Call neetprep education counselor buy neet course complete syllabus.
Thus, heterospory in pteridophytes forms the base of seed habits in gymnosperms. Examples of heterosporous pteridophytes lifeeasy biology. Genera like selaginella, salvinia, marsilea and azolla which produce two kinds of spores, macro large. However, the pteridophytes differ from mosses and seed plants in that both generations are independent and free living. However, there are some pteridophytes which produce two different types of spores differing in size.
Ncert solutions for class 11 biology chapter 3 plant. Important questions for class 11 biology chapter 3 plant. According to rashid1976, only 9 genera of pteridophytes show heterospory,i. Full text of the origin of gymnosperms and the seed habit see other formats stop early journal content on jstor, free to anyone in the world this article is one of nearly 500,000 scholarly works digitized and made freely available to everyone in the world by jstor. Moreover, surprisingly few authors have attempted to formally define heterospory or its presumed ancestral condition, homospory. The structure and development of the sporophylls and. No pteridophytes are cultivated as crop plants, but the leaf buds fiddleheads of some ferns are commercially harvested and canned or frozen. The sporangia show greater specialization than those of ferns. The pteridophytes show heteromorphic alternation of generation. The role of heterochrony article pdf available in taxon 381.
Pteridophytes differ from bryophytes in that the sporophyte is branched and generally much larger and more conspicuous, and from seed plants in that both generations are independent and free living. Heterosporous pteridophytes are the plants that produce two types of spores i. Today this subject is controversial, and scarcely considered in textbooks and journals of botany, in spite of its importance. The socalled epidermis is physiologi cally but not morphologically equivalent to that of seedplants. In this article we will discuss about heterospory and seed habit in pteridophytes. Ncert exemplar class 11 biology solutions plant kingdom.
They are generally photosynthetic in nature and contain pigments, chlorophyll a, and carotenoids, etc. Biology experiment protocols and flow charts, diagrams for biology record work. The sporophyte is the conspicuous and familiar plant body. From free sporing homospory to free sporing heterosporythe origin of sex determination. Aug 06, 2019 evolution of seed habit in selaginella pdf pdf summary the origin of the seedplant life history, and subsequent should be considered two independent, fundamentally distinct evolutionary. Rothwell department of environmental and plant biology, ohio university, athens, oh 45701, usa received 31 october 1994. Heterospory and origin and evolution of seed habitat in land plants pteridophytes. Development of protective layers and nutritive tissue.
Buy isbn9781403930309 at 16% discount by macmillian india ltdnew delhi. Similar to the life cycle of seed plants, the pteridophytes also involves the alternation of generations in its life cycle. Pteridophytes biology encyclopedia plant, body, different. Read heterothally and the seed habit versus heterospory, new phytologist on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Each microsporangium contains a large number of microspores whereas each megasporangium contains. The microspores develop into male gametophyte whereas the megaspores give rise to female gametophyte. Feb 06, 2016 evolution of seed habit, biology lecture sabaq. Evolutionary significance of heterospory and seed development in. Heterosporous pteridophytes produce two types of spores. Heterospory and seed habit are often exhibited by a plant possessing a petiole b ligule. Neet aipmt biology chapter wise solutions plant kingdomcontents1 neet aipmt biology chapter wise solutions plant kingdom1.
In a word, heterangy in combination with homospory and heterothally forms the distinctive features of the seed habit while heterospory represents the culmination of the free. In certain species of selaginella only one megaspore develops within the mega sporangium. Ncert solutions for class 11 biology chapter 3 in pdf form to free download in english medium updated for new academic session 202021. Coenocytic growth phases in land plant development. The heterospory also reduced the size of gametophytic generation. Heterospory originated in some pteridophytes like selaginella. The development of seed habit, seen in presentday gymnosperms and also in angiosperms eliminated the requirement of water during sexual reproduction. The origin of the sporophyte in land plants represents a fundamental phase in plant evolution. It is a condition found in some plants in which a plant produces more than one type of spores. Ncert exemplar class 11 biology solutions plant kingdom multiple choice questions 1. The sexuality of pteridophyte gametophytes can be classified as follows. Megasporophyll of pteridophytes is comparable to which structure of angiosperms stamens ovule carpel microsporophyll.