Biology · Class 11 Science
Ch 3Plant Kingdom — Class 11 Biology, concept-first.
The previous chapter looked at how living organisms as a whole are grouped, following the Five Kingdom system proposed by R.H. Whittaker in 1969, which sorts all organisms into Monera, Protista, Fungi, Animalia and Plantae.
Key concepts
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Algae Classification Basis
Imagine you are handed a big box of coloured pens with no labels and asked to sort them into groups. You would probably start with the most obvious clue — their colour — and then look at other features, such as what kind…
Most relevant Q&A
Chapter contents
The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.
Introduction: Classifying the Plant Kingdom
The previous chapter looked at how living organisms as a whole are grouped, following the Five Kingdom system proposed by R.H.
Algae
Algae are the simplest members of the plant kingdom. They carry chlorophyll, so they make their own food (they are autotrophic), yet their body stays simple and undifferentiated — it is a thallus, mea…
Chlorophyceae
The members of Chlorophyceae are the green algae — the group whose fresh, grass-green colour makes them the most familiar of the algae.
Phaeophyceae
The members of Phaeophyceae are the brown algae, and they belong chiefly to the sea — marine habitats are their main home.
Rhodophyceae
The members of Rhodophyceae are the red algae. Their name comes from the red pigment r-phycoerythrin, which is so abundant in the body that it masks the other colours and gives the group its character…
Bryophytes
Bryophytes are the group of simple land plants that includes the mosses and the liverworts. They are commonly seen growing in moist, shaded places, such as the damp hillsides where they form soft gree…
Liverworts
Liverworts are one of the two groups of bryophytes. They favour moist, shady habitats and are typically found along the banks of streams, on marshy ground, on damp soil, on the bark of trees, and deep…
Mosses
Mosses are the second group of bryophytes. In their life cycle the gametophyte is the dominant, most prominent stage, and this gametophyte passes through two distinct stages.
Pteridophytes
Pteridophytes are a group of plants that includes the horsetails and the ferns. They have several practical uses: they are employed for medicinal purposes, act as soil-binders that hold the soil toget…
Gymnosperms
Gymnosperms are seed-bearing plants whose defining feature is written into their name: gymnos means naked and sperma means seed.
Angiosperms
Angiosperms, commonly called the flowering plants, differ from gymnosperms in a fundamental way. In gymnosperms the ovules lie naked, but in angiosperms both the pollen grains and the ovules are produ…
Summary
The plant kingdom brings together five great groups — the algae, the bryophytes, the pteridophytes, the gymnosperms and the angiosperms.
Exercises
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- 3.1What is the basis of classification of algae?Free
- 3.2When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?Free
- 3.3Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.Free
- 3.4Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of…Preview
- 3.5Write a note on economic importance of algae and gymnosperms.Preview
- 3.6Both gymnosperms and angiosperms bear seeds, then why are they classified separately?Preview
- 3.7What is heterospory? Briefly comment on its significance. Give two examples.Preview
- 3.8Explain briefly the following terms with suitable examples:- (i) protonema (ii) antheridium (iii) archegonium (iv) diplontic (v) sporophyll…Preview
- 3.9Differentiate between the following:- (i) red algae and brown algae (ii) liverworts and moss (iii) homosporous and heterosporous pteridophyt…Preview
- 3.10Match the following (column I with column II) Column I — Column II (a) Chlamydomonas — (i) Moss (b) Cycas — (ii) Pteridophyte (c) Selaginell…Preview
- 3.11Describe the important characteristics of gymnosperms.Preview
Exemplar Problems
Higher-order thinking / exemplar-style practice problems.
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- Q1Cyanobacteria are classified under (a) Protista (b) Plantae (c) Monera (d) AlgaeFree
- Q2Fusion of two motile gametes which are dissimilar in size is termed as (a) Oogamy (b) Isogamy (c) Anisogamy (d) ZoogamyFree
- Q3Holdfast, stipe and frond constitutes the plant body in case of (a) Rhodophyceae (b) Chlorophyceae (c) Phaeophyceae (d) All of the aboveFree
- Q4A plant shows thallus level of organization. It shows rhizoids and is haploid. It needs water to complete its life cycle because the male ga…Preview
- Q5A Prothallus is (a) A structure in pteridophytes formed before the thallus develops (b) A sporophytic free living structure formed in pterid…Preview
- Q6Plants of this group are diploid and well adapted to extreme conditions. They grow bearing sporophylls in compact structures called cones. T…Preview
- Q7The embryo sac of an Angiosperm is made up of (a) 8 cells (b) 7 cells and 8 nuclei (c) 8 nuclei (d) 7 cells and 7 nucleiPreview
- Q8If the diploid number of a flowering plant is 36. What would be the chromosome number in its endosperm? (a) 36 (b) 18 (c) 54 (d) 72Preview
- Q9Protonema is (a) Haploid and is found in mosses (b) Diploid and is found in liverworts (c) Diploid and is found in pteridophytes (d) Haploid…Preview
- Q10The giant Redwood tree (Sequoia sempervirens) is a/an (a) Angiosperm (b) Free fern (c) Pteridophyte (d) GymnospermPreview
- Q11Food is stored as Floridean starch in Rhodophyceae. Mannitol is the reserve food material of which group of algae?Preview
- Q12Give an example of plants with a. Haplontic life cycle b. Diplontic life cycle c. Haplo-diplontic life cyclePreview
- Q13The plant body in higher plants is well differentiated and well developed. Roots are the organs used for the purpose of absorption. What is…Preview
- Q14Most algal genera show haplontic life style. Name an alga which is a. Haplo-diplontic b. DiplonticPreview
- Q15In Bryophytes male and female sex organs are called __________ and _________.Preview
- Q16Why are bryophytes called the amphibians of the plant kingdom?Preview
- Q17The male and female reproductive organs of several pteridophytes and gymnosperms are comparable to floral structures of angiosperms. Make an…Preview
- Q18Heterospory i.e., formation of two types of spores – microspores and megaspores is a characteristic feature in the life cycle of a few membe…Preview
- Q19How far does Selaginella one of the few living members of lycopodiales (pteridophytes) fall short of seed habit.Preview
- Q20Each plant or group of plants has some phylogenetic significance in relation to evolution: Cycas, one of the few living members of gymnosper…Preview
- Q21The heterosporous pteridophytes show certain characteristics, which are precursor to the seed habit in gymnosperms. Explain.Preview
- Q22Comment on the lifecycle and nature of a fern prothallus.Preview
- Q23How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?Preview
- Q24In which plant will you look for mycorrhiza and corolloid roots? Also explain what these terms mean.Preview
- Q25Gametophyte is a dominant phase in the life cycle of a bryophyte. Explain.Preview
- Q26With the help of a schematic diagram describe the haplo-diplontic life cycle pattern of a plant group.Preview
- Q27Lichen is usually cited as an example of 'symbiosis' in plants where an algal and a fungal species live together for their mutual benefit. W…Preview
- Q28Explain why sexual reproduction in angiosperms is said to take place through double fertilization and triple fusion. Also draw a labelled di…Preview
- Q29Draw labelled diagrams of a. Female and male thallus of a liverwort. b. Gametophyte and sporophyte of Funaria. c. Alternation of generation…Preview