Biology CCE Presentation

8/3/2019 Biology CCE Presentation

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Biology CCE

Project


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Classification of Plants


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PLANTAE KINGDOM -

PHYLUM

} Thallophyta

} Bryophyta

} Pteridophyta

} Gymnosperm

} Angiosperm


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THALLOPHYTA

} A phylum of plants of very diverse habit andstructure, including the alg, fungi, andlichens. The simpler forms, as many blue-green alg, yeasts, etc., are unicellular and

reproduce vegetatively or by means of asexualspores; in the higher forms the plant body isa thallus, which may be filamentous or mayconsist of plates of cells; it is commonlyundifferentiated into stem, leaves, and roots,and shows no distinct tissue systems; thefronds of many alg, however, are modified toserve many of the functions of the above-named organs. Both asexual and sexualreproduction, often of a complex type, occurin these forms. The Thallophyta exist almostexclusively as gametophytes, the sporophytebeing absent or rudimentary. By those who donot separate the Myxophyta from theTallophyta as a distinct phylum the latter istreated as the lowermost group in thevegetable kingdom.


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CHARACTERISTICS OF

THALLOPHYTA

1) They are found in moist or wet places.

2) They are autotrophic ,i.e, manufacturetheir own food. Reserve food is generally

Starch.3) They have a cellulose cell wall around

their cells

4) Mechanical & conducting elements areabsent.

5) Sex organs are simple, single celled,there is no embryo formation afterfertilization.


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Bryophyta

} The term bryophyte comesfrom Greek - bryon, "tree-moss,oyster-green" + - fyton "plant.Bryophyte is a traditional name used torefer to all embryophytes (land plants)

that do not have true vascular tissue andare therefore called 'non-vascular plants'.Some bryophytes do have specializedtissues for the transport of water; howeversince these do not contain lignin, they arenot considered to be true vascular tissue.Currently bryophytes are thought not to be

a natural ormonophyletic group; howeverthe name is convenient and remains in useas a collective term. Bryophytes produceenclosed reproductive structures(gametangia and sporangia), but theyproduce neither flowers nor seeds,reproducing via spores.


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Characteristics of Bryophyta

} The green tissue that makes up most of theplant body is not vascularized; it does not havexylem and phloem cells. This absence ofspecialized tissues for transporting water anddissolved food throughout the organism limits

terrestrial forms to being very short plants, sincethe only way to move substances through theplant body is by osmosis and diffusion fromsurface moisture.

} bryophytes do not have roots, but have rhizoids,which are relatively simple, sometimesmulticellular filaments of thin-walled cells thatextend from the photosynthetic tissue into thesoil or other substrate . They anchor the plantsomewhat and in some cases facilitate waterand nutrient uptake.


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Pteridophyta

} Pteridophyta made from two Greekroots that mean winged (pteryz -); and plant (phyto -). The reference is to the wing-like appearance of the compoundleaves (fronds) that are characteristicof most ferns. There are severalnames used for the ferns, amongthem are: Polypodiophyta,Filicinophyta, and Moniliformopses.They grow as perennial herbs, trees,epiphytes, and floating plants

(Figures A-Z). They have exploitedalmost all terrestrial and freshwaterenvironments, and dominate in someof them. The leaves also usually arecompound and are among the mostcomplex leaves of any in the kingdomof green plants.


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Characteristics of Pteridophyta

} Reproduction

Ferns are strongly distinguished from other plantsby their method of reproduction. Instead ofproducing seeds, they reproduce by making spores--microscopic structures that combine with sperm toproduce a new generation.

} HabitatFerns are usually found in border habitats that otherplants find hard to survive in. They grow in rockcrevices, deserts, on mountains and in moist andshady forests. Some species are epiphytes that growwithout soil on the branches of trees.

} Structure

Ferns have fibrous roots. They are generallyconsidered non-woody plants, but some giant fernscan be considered semi-woody. They have greenleaves that provide energy through photosynthesis.New leaves grow out of a tight spiral called afiddlehead. They also have specialized leaves thatproduce spores called sporophylls


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Gymnosperm

} The gymnosperms are a groupof seed-bearing plants thatincludes conifers, cycads, Ginkgo, andGnetales. The term "gymnosperm"comes fromthe Greek word gymnospermos (), meaning "naked seeds", afterthe unenclosed condition of their seeds(called ovules in their unfertilized state).Their naked condition stands in contrastto the seeds or ovules of flowering

plants (angiosperms), which areenclosed during pollination.Gymnosperm seeds develop either onthe surface of scale- or leaf-likeappendages of cones, or at the end ofshort stalks (Ginkgo).


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Characteristics of Gymnosperm

} Gymnosperms do not have and outer-covering or shell around their seeds.

} Gymnosperms do not produce flowersbarring a few exceptions.

} Gymnosperms are heterosporous whichmeans that they produce different maleand female spores.The microsporesdevelop into pollen grainsand the megaspores are in an ovule.

} Gymnosperms produce cones.

} Gymnosperms do not bear fruits.

} Gymnosperms propagate via windpollination


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Angiosperm

} The angiosperms, or flowering plants, are oneof the major groups of extant seed plants andarguably the most diverse major extant plantgroup on the planet, with at least 260,000living species classified in 453 families. Theyoccupy every habitat on Earth exceptextreme environments such as the highestmountaintops, the regions immediately

surrounding the poles, and the deepestoceans. They live as epiphytes (i.e., living onother plants), as floating and rooted aquaticsin both freshwater and marine habitats, andas terrestrial plants that vary tremendously insize, longevity, and overall form. They can besmall herbs, parasitic plants, shrubs, vines,lianas, or giant trees. There is a huge amountof diversity in chemistry (often as a defenseagainst herbivores), reproductivemorphology, and genome size andorganization that is unparalleled in othermembers of the Plant Kingdom. Furthermore,angiosperms are crucial for human existence;the vast majority of the world's crops areangiosperms, as are most natural clothingfibers. Angiosperms are also sources forother important resources such as medicineand timber.


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Characteristics of Angiosperm

} 1) Ovules that are enclosed within acarpel, that is, a structure that ismade up of an ovary, which enclosesthe ovules, and the stigma, a structurewhere pollen germination takes place

} 2) Double fertilization, which leads tothe formation of an endosperm (anutritive tissue within the seed thatfeeds the developing plant embryo)

} 3) Stamens with two pairs of pollen

sacs

} 4) Features of gametophyte structureand development

} 5) Phloem tissue composed of sievetubes and companion cells


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Classification of Angiosperm


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Monocots

} The Monocotyledonae comprise one-quarter of all flowering plant species. Theyinclude some of the largest and mostfamiliar groups of plants, including lilies,orchids, agaves, palms, and grasses.Though often described as having a

stereotype morphology, the monocots areactually quite diverse, ranging from tinyduckweeds to large palms and climbingvines.

} Economically, monocots are perhaps themost important organisms on earth. Ourfour most important foods -- corn, rice,

wheat, and barley -- all come frommonocots. Bamboo and palms are aprimary source of building materials andfibers in many tropical countries. Sugarcane, pineapples, dates, bananas, andmany of our familiar tropical fruits alsocome from monocots.


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Dicots

} The dicotyledons, also known as dicots,are a group of floweringplants whose seed typically has twoembryonic leaves or cotyledons. There arearound 199,350 species within this group.Flowering plants that are not dicotyledons

are monocotyledons, typically havingone embryonic leaf.

} Dicotyledons are not a monophyletic group,and therefore the names "dicotyledons" and"dicots" are, strictly speaking, deprecated.However, the vast majority of "dicots" doform a monophyletic group calledthe eudicots or tricolpates. These may bedistinguished from all other flowering plantsby the structure of their pollen. Otherdicotyledons and monocotyledonshave monosulcate pollen, or forms derivedfrom it, whereas eudicots have tricolpatepollen, or derived forms, the pollen havingthree or more pores set in furrows calledcolpi.


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Monocots vs Dicots


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Phanerogamaes & Cryptogamaes


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Pictures of Phanerogamaes & Cryptogamaes

Phanerogamaes Cryptogamaes


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Credits

} Compiled by

NAME CLASS /SEC ROLL NO.

Souvick Maji IX A 26

DELHI PUBLIC SCHOOL, FARAKKA

Biology CCE Presentation

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