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The plant kingdom is very vast with a number of classifications. A plant can be classified into Thallophyta, Bryophyta, Pteridophyta. They are differentiated on the basis of the structure, presence or absence of transport tissues, and the ability to bear seeds. The Important Questions for Class 11 Biology Plant Kingdom are given below. These will provide a better understanding of the concepts.
Q.1. Which group of algae has mannitol as the reserve food material?
Ans. The Phaeophyceae group or the brown algae has mannitol as the reserve food material.
Q.2. Name the plants with
Q.3. Roots are used for the purpose of absorption. What is equivalent to roots in less developed lower plants?
Ans. 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?
Ans. The male and female sex organs in Bryophytes are called antheridium and archegonium.
Q.5. Match the following:
Ans. Chlamydomonas-Algae Cycas-Gymnosperm Selaginella-Pteridophyte Sphagnum-Moss
Q.6. Cyanobacteria are classified under which kingdom?
Ans. Cyanobacteria are classified under kingdom Monera.
Q.7. What do you mean by anisogamy?
Ans. 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?
Ans. 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?
Ans. 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?
Ans. 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?
Ans. In-Plant kingdom, the artificial system of classification is based on the vegetative characters and androecium structure.
Q.12. What is the Botanical name of sea palm?
Ans. The Botanical name of sea palm is Postelsia palmaeformis.
Q.13.What is Chemotaxonomy?
Ans. Chemotaxonomy is defined as the method of biological classification based on similarities in the chemical constituents of the plants.
Q.1. Why are bryophytes considered amphibians of the plant kingdom?
Ans. 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.
Reproductive parts of pteridophytes and gymnosperms
Reproductive parts of angiosperms
Q.3. Does heterospory have some evolutionary significance in the plant kingdom?
Ans. 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 habit?
Ans. Selaginella gives rise to two kinds of spores, megaspores and microspores. 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.
Ans. Cycas is an evergreen plant that looks like a palm. It exhibits a phylogenetic relationship with pteridophyte. The evolutionary characters include:
Q.6. Describe the life cycle and nature of a fern prothallus.
Ans. 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 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 gamete through pollen tube.
Male gametes reach the female gamete by flowing in water.
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?
Ans. Mycorrhiza is the symbiotic association between fungus and roots of vascular plants. The mycorrhizal association is present in conifers 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 characteristics which are precursors to the seed habits in gymnosperms. Explain.
Ans. 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?
Ans. Algae are economically important in different ways and are discussed below:
Q.1. How is gametophyte a dominant phase in the life cycle of bryophytes?
Ans. 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 bryophyte. 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.
Ans. 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 double fertilization and triple fusion?
Ans. 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?
Ans. 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.
Kingdom Plantae or the plant kingdom is the taxonomic rank that includes algae, bryophytes, pteridophytes, gymnosperms and angiosperms. The very first land plants appeared roughly 470 million years ago, and over the aeons, a spectacular number of plant biodiversity has evolved.
Plant kingdom classification has changed a number of times over the years. For instance, blue-green algae were once considered to be part of the plant kingdom, but today, they are classified under Kingdom Eubacteria. Similarly, lichen was once considered a plant; however, they are composite organisms. In other words, lichens are comprised of two individual organisms – a fungus and a plant. Historically, organisms that could not be classified under animals were grouped under plants.
Today, we do know that this is reasoning is flawed. Plants, in a strict sense, are technically organism that includes green algae and land plants and possess chlorophyll a and b and have plastids that are bound by only two membranes and are capable of photosynthesis and storing starch.
In the strictest sense, the definition of plants extends only to the land plants or the embryophytes. Here, plants include mosses, liverworts, hornworts and all vascular plants.
Prominent Kingdom Plantae examples:
How are algae classified?
Algae can be classified into three main classes:
How are angiosperms different from gymnosperms?
Angiosperms and gymnosperms shared a common ancestor some 300 million years ago. This means they share undeniable similarities with each other. However, a crucial difference that evolved between the two families is that the angiosperms have specialized reproductive structures called flowers. The final product of flowers is fruits.
When the sporophytes of land plants produce spores of two different sexes and sizes, it is called heterospory. In other words, heterospory is the production of spores of two sizes – megaspores and microspores; with each forming a specific type of gametophyte – either a megagametophyte and produces eggs and archegonia or a microgametophyte that produces sperms and antheridia.
Why are blue-green algae not considered to be algae?
Blue-green algae, also called cyanobacteria, are not classified as algae now. Instead, biologists have proposed a modern scheme of classification, taking into account their cell constituents, physiology and DNA features into consideration.
Explain the important characteristics of angiosperms.