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Home , Pteridophyte

NAME OF THE TEACHER: SR. RENCY GEORGE SUBJECT: BIOLOGY TOPIC: CHAPTER -1 : XI MOBILE NO:9340839715

CHAPTER-3 Kingdom Objectives :-

Observe closely to notice features and characteristics of growth and development. Observe and identify differences in plants and . Observe similarities among plants (, , stems, , , )

Learning Strategies:-

• Explain Different systems of Classification. • Differentiate between Artificial and Natural System of Classification. • Explain and its significance. • Differentiate between various classes of Algae. • Explain various modes of reproduction in Algae.

RESOURCES:

i.Text books ii.Learning Materials iii.Lab manual iv.E-Resources,video ,L.C.D etc… CLICK HERE TO PLAY CONTENT RELATED VIDEO ON YOU TUBE. https://youtu.be/SWlVX1gDd98 https://youtu.be/P_MyyxIQzm4 https://youtu.be/KmbFGIiwP4k https://youtu.be/mepU8gStVpg https://youtu.be/fnE01M0YlTc https://youtu.be/xir7xvLi8XE

Contents Introduction Plant kingdom includes algae, , , and angiosperms. ... Depending on the type of pigment possessed and the type of stored food, algae are classified into three classes, namely Chlorophyceae, Phaeophyceae and Rhodophyceae.

Eukaryotic, multicellular, containing and having , are grouped under the kingdom Plantae. It is popularly known as plant kingdom.

• Phylogenetic system of classification based on evolutionary relationship is presently used for classifying plants. • Numerical use computer by assigning code for each character and analyzing the features. • Cytotaxonomy is based on cytological information like chromosome number, structure and behaviour. • Chemotaxonomy uses chemical constituents of plants to resolve the confusion.

Algae: These include the simplest plants which possess undifferentiated or thallus like forms, reproductive organs single celled called gametangia. It includes only Algae. Characteristic of Algae

• Plant body is thallus, which may be unicellular, colonial, filamentous or parenchymatous.

• Usually aquatic but a few are also found in moist terrestrial habitats like trunks, wet rocks, moist soil, etc.

• Vascular tissues and mechanical tissues are absent.

• Reproduction is vegetative by fragmentation, asexual by formation (zoospores) and sexual reproduction by fusion of two which may be Isogamous (Spirogyra), Anisogamous (Chlamydomonous) or Oogamous (Volvox).

Green Algae Brown Algae

Mostly fresh water and sub Mostly marine. Mostly marine. aerial.

Unicellular organisms Unicellular species are Unicellular species fewer. abundant. absent.

Chlorophyll a and b type. Chlorophyll a and c type. Chlorophyll a and d type.

Reserve food is Reserve food is laminarin. Reserve food is floridean starch.

Cell wall contains Cell wall contains cellulose and poly- Cell wall is of cellulose. and algin. sulphate esters.

Fucoxanthin is absent Fucoxanthin present. Phycoerythrine is present.

Zoospores present. Zoospores present. Zoospores absent.

Chlamydomonas, Ulothrix, Focus, Sargassum, Polysiphonia, Gelidium, Porphyra etc. spirogyra. ectocarpus.

• cycle is various- haplontic, diplontic or diplohaplontic.

Economic importance-

1. A number of brown algae ( Laminaria, Sargassum) are used as food in some countries. 2. Fucus and Laminaria are rich source of Iodine. 3. Laminaria and Ascophyllum have antibiotic properties. 4. Alginic acid is obtained from Fucus and Sargassum, which is used as emulsions. Bryophytes – They are non-vascular and liverworts that grow in moist shady region. They are called amphibians of plants kingdom because these plants live on soil but dependent on water for sexual reproduction.

Characteristic features-

• Live in damp and shady habitats, found to grow during rainy season on damp soil, rocks, walls, etc.

• The dominant phase or plant body is free living .

• Roots are absent but contain

• Vegetative reproduction is by fragmentation, tubers, gemmae, etc. sex organs are multicellular and jacketed. The male sex organ is called . They produce biflagellate antherozoids. The female sex organ called is flask-shaped and produces a single egg.

• is dependent on gametophyte for nourishment. Bryophytes Hepaticopsida (Liverworts)

• The plant body of a liverwort is thalloid, e.g., Marchantia. The thallus is dorsiventral and closely appressed to the substrate.

• Asexual reproduction in liverworts takes place by fragmentation, or by the formation of specialised structures called gemmae. • Gemmae are green, multicellular, asexual buds, which develops in small receptacles called gemma cups. The gemmae becomes detached from the parent body and germinate to form new individuals

• During sexual reproduction, male and female sex organs are produced either on the same or on different thalli. The sporophyte is differentiated into a foot, seta and . produced within the capsule germinate to form free-living . Bryopsida (Mosses)

• The gametophyte of mosses consists of two stages- the first stage is protonema stage, which develops directly from spores. It is creeping, green and frequently filamentous. The second stage is the leafy stage, which develops from secondary protonema as lateral having upright, slender axes bearing spirally arranged leaves.

• Vegetative reproduction is by the fragmentation and budding in secondary protonema. In sexual reproduction, the sex organs antheridia and archegonia are produced at the apex of the leafy .

• in mosses are more developed and consist of foot, seta and capsule.

• Common examples are Funaria, Polytrichum, Sphagnum etc. Pteridophytes

• They are seedless vascular plants that have sporophytic plant body and inconspicuous gametophyte. Sporophytic plant body is differentiated into true stem, roots and leaves.

• Vascular are present but vessels are absent from and companion cells and sieve tube are absent.

• Sporophytes bear sporangia that are subtend by like appendages called . In some plants () compact structure called strobili or cone is formed. • Sporangia produce spores by meiosis in spore mother cells. Spores germinate to produce multicellular thalloid, .

• Gametophyte bears male and female sex organ called antheridia and archegonia. Water is required for fertilisation of male and female gametes.

• Most of Pteridophytes produce spores of similar kind (homosporous) but in Selginella and Salvinia, spores are of two kinds (heterosporous) larger called that produce female gametophyte and smaller that produce male gametes.

Gymnosperms: • Gymnosperms are those plants in which the are not enclosed inside the

Monocotyledons Dicotyledons wall and remain exposed before and after fertilisation.

• They are perennial and woody, forming either bushes or . Some are very large (Sequoia sempervirens) and others are very small (Zamia pygmia).

• Stem may be unbranched(Cycas) or branched(Pinus). is taproot. Leaves may be simple or compound.

• They are heterosporous, produce haploid microspore and megaspore in male and female Strobili respectively.

• Male and female gametophytes do not have independent free-living existence. occurs through air and zygote develops into and ovules into seeds. These seeds are naked.

• Example- Pines, Cycus, Cedrus, Ginkgo, etc. Angiosperms

• grain and ovules are developed in specialized structure called . Seeds are enclosed inside the .

• Size varies from almost microscopic Wolfia (0.1cm)to tall tree Eucalyptus (more than 100m

• The male sex organs in a flower is the . It contains pollen grain.

• The female sex organs in a flower is the pistil or the carpel. Pistil consists of an ovary enclosing one or many ovules. Within ovules are present highly reduced female gametophytes termed embryo-sacs.

• Each embryo-sac has a three-celled egg apparatus – one and two synergids, three antipodal cells and two polar nuclei. The polar nuclei eventually fuse to produce a diploid secondary nucleus. Angiosperms are further classified into:

• Monocotyledons

• Dicotyledons 1. Single cotyledons. 1. Two cotyledons. 2. Parallel venation. 2. Reticulate venation. 3. Fibrous root system. 3. Tap root system. 4. Closed . 4. Open vascular bundle. 5. More number of vascular bundles. 5. Less number of vascular bundles. 6. Banana, wheat, rice. 6. Gram, mango, apple.

• Double fertilisation- Each pollen grain produce two male gametes. One gametes fuse with egg to form embryo. This is called Syngamy. Other gametes fuse with two polar nuclei to form , triple fusion. Since fertilisation takes place twice, it is called double fertilisation. Alternation of generation Different plant groups complete their life cycles in different patterns. Angiosperms complete their life cycle in two phases- a diploid sporophytes and haploid gametophyte. The two follows each other. This phenomenon is called alternation of generation.

1. 1. Haplontic- Saprophytic generation is represented by only the one-celled zygote. Meiosis in zygote results into haploid spores to form gametophytes, which is the dominant vegetative phase. Example- Volvox, Spirogyra etc. 1. 1. Diplontic- Diploid sporophytes is dominant, independent, photosynthetic plants. The gametophyte is represented by single to few celled. All bearing plants fall under this category. 1. Haplo-diplontic- Both phases are multicellular and intermediate condition is present. It is present in Bryophytes and Pteridophytes. Question and Answers from Chapter-3

Short Answer Type Questions:- Q.1. Which group of algae has mannitol as the reserve food material? A.1. The Phaeophyceae group or the brown algae has mannitol as the reserve food material. Q.2. Name the plants with 1. Haplontic life cycle 2. Diplontic life cycle 3. Haplo-diplontic life cycle

A.2.

1. Haplontic life cycle- Volvox 2. Diplontic life cycle- All seed-bearing plants 3. Hapiodiplontic life cycle- Bryophytes

Q.3. Roots are used for the purpose of absorption. What is equivalent to roots in less developed lower plants? A.3. In less developed lower plants root-like structures called rhizoids are present. For eg., in bryophytes and pteridophytes. Q.4. What is male and female sex organs in Bryophytes are called as? A.4.The male and female sex organs in Bryophytes are called antheridium and archegonium. Q.5. Match the following:

Column I II

Chlamydomonas

Cycas

Selaginella Algae

Sphagnum A.5. Chlamydomonas-Algae Cycas-Gymnosperm Selaginella-Pteridophyte Sphagnum-Moss Q.6. are classified under which kingdom? A.6. Cyanobacteria are classified under kingdom Monera. Q.7. What do you mean by anisogamy? A.7. It is a type of sexual reproduction that involves the fusion of two motile gametes that are dissimilar in size. Q.8. How many cells an embryo sac is made of? A.8. The embryo sac is made up of two synergids, one egg cell, three antipodal cells, and one secondary nucleus. Q.9. What are the three groups of plants that bear archegonia? A.9. Bryophytes, pteridophytes, and gymnosperms are the three groups of plants that bear archegonia. Q.10. Why are both gymnosperms and angiosperm in spite of both bearing seeds? A.10. This happens because in gymnosperms the seeds are not present inside the fruit, while in angiosperms they are enclosed inside the fruit. Q.11.What is an artificial system of classification? A.11. In-Plant kingdom, the artificial system of classification is based on the vegetative characters and androecium structure. Q.12.What is the of sea palm? A.12.The Botanical name of sea palm is Postelsia palmaeformis. Q.13.What is Chemotaxonomy? A.13. Chemotaxonomy is defined as the method of biological classification based on similarities in the chemical constituents of the plants.

Short Answer Type Questions Q.1. Why are bryophytes considered amphibians of the plant kingdom? A.1. Bryophytes are considered amphibians of the plant kingdom because they depend on water for the movement of male gametes called antherozoids to reach archegonium for fertilization. Q.2. Compare the various reproductive parts of pteridophytes and gymnosperms with those of angiosperms. A.2.

Reproductive parts of pteridophytes and gymnosperms Reproductive parts of angiosperms

Cone Flower

Megasporophyll Anther

Megasporangium

Microsporangium Stamen

Microsporophyll Pistil/Carpel Q.3. Does heterospory have some evolutionary significance in the plant kingdom? A.3. Pteridophytes are intermediate between bryophytes and gymnosperms. Primitive pteridophytes are homosporous while the later pteridophytes are heterosporous. Bryophytes are homosporous and gymnosperms are heterosporous. Q.4. How far does Selaginella fall short of seed ? A.4. Selaginella gives rise to two kinds of spores, and . These spores germinate and give rise to male and female gametophytes. But, due to lack of integument around the megasporangium, Selaginella falls short of seed habit. Q.5. Discuss the phylogenetic relationship of Cycas with any other group of plants. A.5. Cycas is an evergreen plant that looks like a palm. It exhibits a phylogenetic relationship with pteridophyte. The evolutionary characters include:

• Shedding of seed when the embryo is immature. • Slow growth. • Monocyclic . • Little . • Leaf-like megasporophylls. • Circinate ptysix. • Persistent leaf bases. • Arrangement of is well-defined archegonia. Q.6. Describe the life cycle and nature of a prothallus. A.6. The life cycle of Prothallus: The life cycle of fern exhibits alternation of generations. The fern prothallus is multicellular, free-living, haploid, autotrophic, and thalloid structure. It is developed from the spores produced after reduction division by saprophyte. These spores germinate with a germ tube. It forms a filament of 3-6 cells and rhizoids at the base which develops into a gametophytic plant later. Q.7. Differentiate between the male and female gametophytes of pteridophytes and gymnosperms. A.7. Male Gametophytes:

Gymnosperms Pteridophyte

A distinct male gametophyte is always present. A distinct male gametophyte is absent.

Antheridium is not present. Antheridium is present.

Male gametes may or may not be flagellated. Male gametes are flagellated.

Male gametes reach the female through Male gametes reach the female gamete by flowing . in water. Female Gametophytes:

Gymnosperms Pteridophyte

A distinct gametophyte is always present. A distinct gametophyte may or may not be present.

Female gametophyte does not leave the parent plant. It is independent of the parent plant.

Enclosed inside an ovule. Not enclosed inside the ovule. Q.8. Mycorrhiza and coralloid roots are found in which plants? What do these terms mean? A.8. Mycorrhiza is the symbiotic association between and roots of vascular plants. The mycorrhizal association is present in such as Pinus, Cedrus, etc. Coralloid roots are present in Cycas. Coralloid roots are present in clusters at the base of the stem and protrude over the ground. It is greenish in colour and dichotomously branched. Q.9. The heterosporous pteridophytes exhibit certain characterstics which are precursors to the seed habits in gymnosperms. Explain. A.9. Heterospory is the production of two types of spores; the megaspores and the microspores. The microspores produce male gametophyte which produces male gametes, while the megaspores produce female gametophyte which produces archegonia and provides nourishment to the embryo. Thus, heterospory leads to a reduction of the gametophyte. Thus, heterospory in pteridophytes forms the base of seed habits in gymnosperms. Q.10.What is the importance of Algae? A.10. Algae are economically important in different ways and are discussed below:

1. Helps in carbon dioxide fixation. 2. They are the simplest forms of producers in a food chain. 3. Helps in increasing the dissolved oxygen level in the environment. 4. There are different species of algae, which are used as a source of food. 5. They are a source of crude oil and also for many pharmaceutical and industrial products that are used by humans.

Long Answer Type Questions Q.1. How is gametophyte a dominant phase in the life cycle of bryophytes? A.1. Gametophyte bears the male reproductive organ antheridia and female reproductive organ archegonia, thereby, producing male gametes (antherozoids) and female gametes (egg cell). A gametophyte is a dominant form and the most familiar phase of the life cycle of . The antherozoid fuses with the egg to produce a zygote. Zygote forms a multicellular body known as the sporophyte. Q.2. Describe the life cycle of a plant. A.2. The life cycle of a plant starts as a seed. The seed germinates and grows like a plant. The plant produces flowers which produce seed in fruit on fertilization. The plant dies and leaves seeds behind which germinate to form a new plant. Q.3. What do you mean by and triple fusion? A.3. In this process, one male gamete fertilizes the egg and forms a diploid zygote. The other male gametes fuse with the two polar nuclei forming a triploid zygote that develops into the endosperm. This is known as double fertilization. The three haploid nuclei fuse to form endosperm. It is known as triple fusion. Q.4. What are parasitic algae? A.4. Parasitic algae are also called as the common plant pathogen. These species of algae are most commonly seen in warm, humid climates and are usually found in the leathery leaf plants such as litchi, hollies, magnolias, and viburnums. Parasitic algae are the major causes of foliar disease and red rust of tea leaf. Cephaleuros is an example of parasitic green algae.