you must have often seen a slimy green layer on rocks lying close to the sea this green layer is algae these are simple salud flora fill bearing autotrophic organisms you can spot algae growing on moist rocks and stones and fresh water and on wood Algie come in different forms and sizes for instance le'me Dominus is unicellular whereas war Vox is of colonial form and spirogyra is filamentous on the other hand helps form massive plant bodies Algie reproduce through vegetative sexual and sexual methods vegetative reproduction occurs by the process of fragmentation we're in each fragment develops into a phallus while asexual reproduction takes place through spores like zoospores and germinate into new plants during sexual reproduction to beliefs views to form a new organism based on the size of the gametes sexual reproduction can be further divided into isogamous I saw Gomes and Wacha mess reproduction when the fusion is between two gametes of similar size the reproduction is called isogamous the gametes in this case can be flagellated as in chlamydomonas none flagellated as in spirogyra when fusion takes place between two gametes of dissimilar sized the reproduction is termed as an ice auger --mess verga --mess is a fusion between a large non-motile female gamete and a small Hotel male gamete Algie perform a wide variety of functions they carry out carbon dioxide fixation and also increased the level of dissolved oxygen in their immediate surroundings through photosynthesis they produce energy-rich compounds that form food for aquatic organisms Algie are also used for commercial purposes for instance egg are obtained from Gilliam and grassle area is used to prepare ice creams and jellies based on the type of pigment and the type of stored food we can classify algae into draw-off I say fee fi say and Rodef I say Alameda Mona's while Vox and spirogyra are some members of the class glorify si they are commonly called green algae and can have a unicellular luenell or filamentous body their cell wall is rigid as the outer layer is made of pectus and the inner layer of cellulose the cell has several chloroplasts that contain paranoids structures that have starch and protein in definite chloroplasts you can find the localized pigments chlorophyll a and B that give the algae the color of green grass green algae can reproduce vegetatively through fragmentation and asexually by flagellated zoospores as well as sexually feel phi c is another class of algae and ekta kapoor s-- dictator laminaria us members these species commonly termed as brown algae are mostly found in brackish or saltwater they display a wide variety in form and size instance Hecht okapis displays filamentous form whereas cabs are profusely branched and can measure hundred meters in height they also vary in color due to the varying concentration of the pigments xanthophylls and Foucault xanthine apart from these pigments chlorophyll a see and carotenoids are the other major pigments found in brown algae let's now take a look at the body structure and cellular structure of brown algae the plant body consists of a frond a leaf like photosynthetic organ and a Stipe that functions as a stalk the front and Stipe are attached to the substratum by a holdfast the vegetative cells of brown algae have a cellulosic wall which usually has an outer gelatinous coating of elgyn the protoplast inside the cell has plastids and essentially located vacuole and mucus brown algae produce through fragmentation and asexually through by flageolets pause on the other hand in sexual reproduction the gametes unite either in water or within the organ rudder phi c is another class of algae whose members include vollis afonya grassle area and gle idiom the members are often called red algae the red color is due to a high concentration of the red pigment our psycho Eritrean the thali of red algae are multicellular and food is stored as floridian starch inside the cells red algae are found in brackish and saltwater and mostly in warmer areas reproduce vegetatively sexually through non-motile spores and sexually through motile spores thus we have seen that there are a variety of algae that thrive in the aquatic habitat it is common to see a green cover growing over rocks bricks and walls after heavy showers this green color is nothing but moss which is a type of bryophyte plants that usually grow in damp humid and shaded localities they are also called amphibians of the plant kingdom because though bryophytes grow in soil they need a moist habitat for sexual reproduction let's now take a look at the different parts of a bryophyte the plant body is felis like and is either prostrate or erect it is attached to the substratum by unicellular or multicellular rhizoids the plant body does not have true roots stem or leaves but possesses similar structures the main plant body of a bryophyte is haploid it is also called a gametophyte as it produces the meats the plant body has both male and female gametophyte which bear the male and female sex organs respectively the male sex organs are called the antheridia and they produce by flageolet antara Zoids the female sex organs called the archegonia a flask shaped and each produces a single egg during fertilization antheridium releases anthro Zoids in water where they come into contact with the mouth of the archegonium one anthro Zoid fuses with the egg to form a zygote the zygote in turn produces a multicellular body called the sporophyte the sporophyte gets its nutrition from the gametophyte some cells of the sporophyte undergo meiosis to produce haploid spores spores germinate to produce a gametophyte bryophytes out of two types liverworts and mosses you can find liverworts in moist and shady environs such as barks of trees the plant body phallus is dorsal-ventral and oppressed to the substrate however in the case of leafy liverworts the plant body bears tiny leaf like appendages in two rows on the stem like structures liverworts reproduce both sexually and sexually in the case of asexual reproduction we observe fragmentation of the phallus asexual reproduction also occurs when Jamie are formed they are green cellular asexual buds that separate from the parent and develop into new individuals they develop in small receptacles called gemma cups located on the fellas in the case of sexual reproduction the male and female sex organs are produced either on the same or on different phallus mosses are another type of bryophytes few Neriah tricking and swagman as common species of moss the MAS undergoes several stages in life quieren the gametophyte stage is the most predominant one the gametophyte stage has two sub stages - NEMA and leafy stage proto NEMA stage the spore develops into a proto NEMA fed like chain of cellars the proto NEMA is creeping green branched and filamentous the second stage is the leafy stage where the primary protein IVA develops into the secondary protein EEMA as a lateral bud the buds consist of upright slender axes that bear spirally arranged leaves attached to the soil through branched rhizoids organs developed during the leafy stage mosses reproduce vegetatively and sexually vegetative reproduction is by fragmentation and budding in the secondary protein EEMA sexual reproduction the male and female sex organs are produced at the apex of the leaf he shoots let's now look at the uses and importance of bryophytes Magnum provides beat which is used as fuel also form a dense mat thereby allowing rainwater to percolate into the ground this prevents rainwater from running off and the subsequent soil erosion fights such as mas are also ecologically important as along with lichens they are always the first to colonize rocks moreover they decomposed the rocks and make the area suitable for the growth of higher plants thus we have seen that bryophytes have several uses you have probably seen ferns growing in gardens or in someone's backyard funds are a type of terror to fight jello fights are plants that forage in a damp cool and shady habitat although some species also grow in sandy soil conditions [Music] they occupy a special place in plant evolution as they were the first terrestrial plants to possess vascular tissues and true root stem and leaves the leaves of a pteridophytes are large as in ferns or small as in the case of selaginella jeredy fights are widely used as ornamental plants soil binders and for medicinal purposes based on the organization of the plant body including the nature of the leaf and location of sporangia classified as Sulabh cedar like op sitter spin-up cedar and tarapada the lifecycle of a chariot of height begins when the plant body a sporophyte bears sporangia which are subtended by leaf-like appendages called sporophylls however in some genera like Equus Eitam sporophylls might form distinct and compact structures called Strobel a or cones the speranza produced spores in spore mother cells by meiosis which germinate into gametophyte s-- gold truth Alice / small multicellular free-living and mainly photosynthetic gametophyte which grows only in cool damp and shady places the pro thallus also bears the male and female sex organs the antheridium and archegonium the antheridium produces the male gametes called anti Zoids whereas the ik aghanim produces an egg when released antara Zoids traveled through water and eventually reached the mouth of the archegonium where each one fuses with an egg to form a zygote this zygote develops into a young embryo which further develops into a multicellular and well differentiated young sporophyte and ultimately into a mature sporophyte this completes the life cycle of a charity fight which is divided into the gametophyte ik phase and the sporophyte ik phase and freeze Derrida fights can be homeless POTUS or heterosporous almost porous pteridophytes produced spores of similar kind while heterosporous pteridophytes produced two different types of spores large or megaspores and small or micro spores megaspores germinate into female gametophyte which produce eggs while microspores germinate into male gametophyte which produce antara Zoids the egg and anthracite fuse to form a zygote which develops into a young embryo which then gives rise to a sporophyte these pteridophytes occupy an important place in the plant kingdom as they were the first plants to have true roots and leaves as well as vascular tissues it is common to find trees such as - cedrus and cycas growing in the cooler regions of India all of them are gymnosperms a group of plants in which the ovules are not enclosed by an ovary wall and remain exposed or naked before fertilization as well as post fertilization when they develop into seeds these seeds germinate to give rise to new plants if you take a look at the morphology of gymnosperms notice that most of them have tap roots moreover in some genera such as - the roots have a fungal Association in the form of mica riser while in other genera such as psychos small specialized roots called coronoid roots have an association with into fixing cyanobacteria the stems of a gymnosperm can be branched or unbranched use can be compound as in cycas or simple as in Jenko moreover these leaves are well-adapted to extend extreme climatic conditions as seen in balsam fir it's needle-like leaves reduce the surface area which in turn loss of water due to transpiration even the thick cuticle and sunken stomata on the leaves reduce the rate of water loss the reproductive structure of a gymnosperm is called a struggle as' or a and gymnosperms have both male and females trouble I interestingly thus trouble I may be born on the same tree as seen in Pinus or on different trees as in psychos the mail struggle as' has spirally arranged leaf-like structures called micro sporophylls which bear microsporangia a structure that produces haploid micro spawns the few microspores develop into male gametes called pollen grains and the rest degenerate named for males trouble a is microsporangia the females trouble Asst is a cluster of mega sporophylls which bears ovules the megasporangium or nacelles the megasporangium surrounded by a layer of envelopes produces haploid megaspores and a megaspore mother cell distinctly different from the other mega spawns the cell undergoes meiosis to give rise to four haploid megaspores one of these spores develops into a multicellular female gametophyte the female gametophyte further bears two or three female sex organs called archegonia develop inside the ovule the development of archegonia is followed by the fertilization process during which pollen dreams released from the micro sporangium are carried by air currents and come in contact with the micro pile and opening in the ovules a pollen tube sprouts from the pollen grain and grows towards the archegonium charges the male gametes these gametes fuse with the egg to form a zygote [Music] post fertilization the zygote develops into an embryo and the ovule into a seed interestingly gymnosperms were the first plants to have a seed habit today gymnosperms are widely used to make products such as varnish and cosmetics they also provide us with lumber that's used to make furniture you must have come across banana plantations apple orchards or herbs such as basil you may have also seen flowers such as Lotus and roses growing in ponds and gardens all these are species of flowering plants also called angiosperms these are plants in which the ovules develop inside the flowers the seeds too are enclosed in fruits and they can be monocotyledonous or dicotyledons a typical flower of an angiosperm contains the stamen and the pistol the male and female sex organs respectively the stamen consists of two parts filament and anther the micro score Anja inside the anther contain the microspore mother cells these mother cells undergo meiosis to produce microspores which then develop into pollen grains the male gametophyte the pollen grains are produced inside the anther on the other hand the pistol consists of the stigma at the tip followed by the style in the middle and an ovary at the base the ovules or the megasporangium are present inside the ovary these are views contain the megaspore mother sim which following meiosis develops into the haploid female gametophyte called the embryo sac the embryo sac has a three celled egg apparatus consisting of one egg cell to synergies three antipodal cells and two polar nuclei the polar nuclei eventually fuse to produce a diploid secondary nucleus the embryo sac now becomes ready for fertilization which in the case of angiosperms takes place by a process called pollination during pollination the antha disperses the pollen grains which are then carried by agents such as the wind and insects and are deposited over the stigma of a pistol here the pollen grain germinates and produces a pollen tube this tube penetrates the tissues of the stigma and style to enter the embryo sac inside the oven it discharges to male gametes inside the embryo sac while one gamete fuses with the egg cell to produce a zygote the other gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus this event is called double fertilization as it involves two fusions interestingly double fertilization is observed only in angiosperms lizz Asian and anti poodles regenerate the zygote develops into an embryo and the primary endosperm nucleus develops into an endosperm which nourishes the zygote simultaneously the ovule develops into a seed and the ovary into a fruit the seed germinates and the embryo develops into a new plant angiosperms are one of the biggest plant groups and they grow in diverse habitats such as land and water as well as in different climatic conditions besides being a source of food the suppliers with fuel fodder and medicines thus and sperms form an integral part of the ecosystem as well as of our daily lives if you observe the lifecycle of any sexually reproducing plant you will notice that it alternates between a sparrow phytic generation and the meta phytic generation this is termed as alternation of generations in the lifecycle of the fern for instance the main plant body no Madras what a fight mez sporangia which produce haploid spores through meiosis these paws undergo mitosis and germinate into a pro phallus Mehta fight with peptide cells Seles where's the antheridium and archegonium that respectively produce an thorough Zoids and egg the haploid male and female gametes the fusion of these haploid gametes results in the formation of a diploid zygote which undergoes mitosis to reproduce a diploid young sporophyte the young sporophyte soon matures into an adult sporophyte completing the lifecycle the plant body thus alternates between a sporophyte generation and a gametophyte ik generation however in different plant groups either the sporophyte of generation or the gametophyte ik generation is the dominant phase in other words persist for long a period this difference gives rise to three patterns of lifecycle in plants antek lifecycle the planting life cycle and haplotype luntik life cycle in the hypnotic lifecycle observed an algae such as Chlamydomonas spirogyra and Volvox the sporophyte of generation is represented by a single-celled diploid zygote and there are no free living sporophytes ms:i goat undergoes meiosis to form haploid spores which divide mitotically to produce a free-living gametophyte since mitosis occurs only in the haploid phase tomato fights are also called haplin's and the life cycle is called the hypnotic life cycle we're in the phytic generation is the dominant phase in the diplomatic lifecycle observed in gymnosperms and angiosperms Metro phytic generation is represented by a single or a few celled gametophyte on the other hand the dominant sporophyte ik generation is represented by a diploid free living and photosynthetic sporophyte the haplotype luntik lifecycle observed in bryophytes and pteridophytes both sporophyte ik and gametophyte ik generations are multicellular and free living however the dominant phases are different in the lifecycle of bryophytes and pteridophytes in bryophytes for instance living thyroid photosynthetic and erect haploid gametophyte represents the dominant phase on the other hand the spotter phytic generation is short-lived during which the multicellular sporophyte is totally or partially dependent on the gametophyte for its Anchorage and nutrition in pteridophytes the photosynthetic sporophyte with vascular tissues is the dominant phase that alternates with the haploid pendant cellular saprophytic or autotrophic gametophyte from bryophytes and pteridophytes certain algae such as Hector coppice and police afonya also exhibit the haplotype luntik life cycle thus every plant cycle is alternation of the spawn of phytic with the gametophyte expels however the dominant phase differs in different plant groups