class 11 chapter 4 Plant Kingdom ppt

2. Types of Biological classifications
There are three types of biological classifications. They are:-
● Artificial System
● Natural System
● Phylogenetic System

3. Artificial System of Classification
● Earliest system of classification.
● Based on vegetative characters or superficial
morphological characters like habit, number, colour,
shape of leaves, etc.
● Linnaeus artificial system of classification was based on
the androecium structure.

4. Drawbacks:-
● Separated closely reated species.
● Equal weightage of vegetative and sexual characteristics.

5. Natural System of Classification
● Based on natural affinities among organisms.
● Considers external and internal features.
● Classification given by George Benthem & Joseph Dalton
Hooker.

6. Phylogenitic System of Classification
● Based on evolutionary relationship among the
organisms.
● Assumes that organisms in the same taxa have a
common ancestor.

10. ● Simple.
● Thalloid.
● Autotropic.
● Chlorophyll bearing.
● Aquatic(fresh water and marine)organisms.
● Some occur in association with fungi called lichen.
● Some occur in association with animals .(sloth bear)
● Form and size are variable.
● Vegetative reproduction by fragmentation.
● Asexual reproduction by production of spores (zoospores).
● Sexual reproduction by fusion of gamates.

11. (Isogamous, Anisogamous, oogamous).
● Fix half of the total CO2 on the earth, through photosynthesis.
● Increase the level of dissolved oxygen.
● Primary producers and the basis of the food cycles of all
aquatic animals.
● Marine algae(about 70%) used as food.
● Agar is used to grow microbes and in ice-creams and jellies.
● Some marine red and brown algae produce carrageen and
hydrocolloids.
● Protein rich unicellular algae are used as food
supplements by space travellers.

12. ● It is divided into three.
● Chlorophyceae(green algae), Phaeophyceae(brown
algae), Rhodophyceae(red algae).

14. ● Unicellular.
● Colonial.
● Filamentous.
● Green colour due to the pigment chlorophyll a & b in
chloroplasts.
● Chloroplasts may be discoid, plate like, reticulate, cup
shaped, spiral and ribbon shaped.
● Most of them have one or more pyrenoids in chloroplast.
● Some algae store food as oil droplets.
● Have rigid cell wall made of an inner cellulose layer and
an outer pectose layer.

15. ● Examples:- Chlamydomonas ; Volvox ; Ulothrix ;
Spirogyra ; Chara.

16. Phaeophyceae

17. ● Mostly marine.
● Show great variation in size and form.
● Pigments present are chlorophyll a,c, carotenoids and
xanthophylls.
● Vary colour from olive green to brown depending on the
amount of xanthophyll pigment and fucoxanthin.
● Food stored as complex carbohydrates(laminarin or
manitol)
● Vegetative cells have a cellulosic wall covered by a
gelatinous coating of algin.

18. ● Protoplast contains plastids, central vacuole and nucleus.
● Body attached to a substratum by a holdfast and has a
stalk(stipe) and leaf like photosynthetic organ is found.
● Vegetative reproduction by fragmentation.
● Asexual reproduction by pear shaped biflagellate
zoospores.
● Sexual reproduction by isogamous, anisogamous and
oogamous.
● Examples:- ectocarpus, dictyota, laminaria, sargassum
and fucus.

20. Red Algae

21. ● Have red thalli due to the red pigment r-phycoerythrin.
● Mostly marine and also occur in regions close to the
surface of water and at great depths in oceans.
● Mostly multicellular.
● Have complex body organisation.
● Food stored as floridean starch.
● Vegetative reproduction by fragmentation.
● Asexual rproduction by non-motile spores.
● Sexual reproduction by oogamous.
● Examples:- polysiphonia, porphyra, gracilaria

23. BRYOPHYTES

24. ● Called as Amphibians of the plant kingdom.
● They can live in soil, but need water for sexual
reproduction.
● Occur in damp, humid, and shaded localities.
● Body is thallus-like and prostrate or erect attached to the
substratum by unicellular or multicellular rhizoids.
● Lack true roots, leaves and stem.
● May possess root-like, leaf-like or stem-like structures.
● Main plant body is haploid.
● Produce gametes therefore, called as gametophytes.

25. ● Sex organs are multicellular.
● Male sex organ is antheridium which produce
antherozoids.
● Female sex organ is archegonium which produce single
egg.
● Antherozoids are released to water and meets
archegonium.
● Antherozoids fuses with the egg to form zygote.
● Zygote produce multicellular body called sporophyte.
● Sporophyte is not free living.

26. ● Sporophyte derives nourishment from the photosynthetic
gametophyte.
● Some mosses provide food for herbaceous
mammals,birds, etc.
● Species of Sphagnum(a moss) provide peat.
● Used as fuel.
● Has water holding capacity so that can be used as
packing trans-shipment of living materials.
● Mosses along with lichens decompose rocks making the
substrate suitable for the growth of higher plants.

27. ● Substrate can prevent soil-erosion.
● Are divided into two:-
(i) Liverworts
(ii) Mosses

29. ● Moist and shady habitat.
● Body is thalloid.
● Thallus is dorso-ventral and closely appressed to the
substrate.
● Leafy members have tiny leaf-like appendages in two
rows on the stem like structure.
● Asexual reproduction by fragmentation and gemme
formation.
● Gemme are green, multi-cellular, asexual buds that
develop in smal receptacles on the thalli.

30. ● Gemme are detached from the parent body and germinate
to form new individuals.
● Sexual reproduction - male and female sex organs are
produced on the same or different thalli.
● Sporophyte is differentiated into foot, seta and capsule.
● After meiosis, spores are produced within the capsule.
● These spores germinate to form free-living gametophyte.

33. ● Predominant stage is called gametophyte.
● Consist of two stages protonema and leafy stage.
● Vegetative reproduction by fragmentation and budding.
● Antheridia and archegonia are produced at the apex of
leafy shoots.
● After fertilisation, zygote develops to a sporophyte having
foot, seta and capsule.
● Sporophyte is elaborate than in liverworts.
● Capsule contains spores, formed after meiosis.
● Mosses have an elaborate mechanism of spore dispersal.

34. ● Examples:- Funaria, Sphagnum, Polytrichum.

35. PTERIDOPHYTES

36. ● Include horsetails and ferns.
● Found in cool, damp and shady areas.
● Flourish well in sandy-soil.
● First terrestrial plants to possess vascular tissues i.e.,
xylem and phloem.
● Dominant phase is sporophyte.
● Differentiated into true roots, stem and leaves.
● Leaves are small or large.
● Used for medicinal purposes.
● Used as soil binders.

37. ● Grown as ornamentals.
● Bear sporangia that are subtended by leaf like
appendages called sporophylls.
● Sporophyll form distinct compact structures called
strobili or cones.
● Sporangia produce spores by meiosis in mother cells.
● Spores germinate to give inconspicuous, small,
multicellular, free living, mostly photosynthetic, thalloid
gametophyte called prothallus.
● Thalloid requires cool, damp, shady places to grow,

38. ● Need water for fertilization.
● Gametophytes bear male and female sex organ
antheridia and archegonia.
● Water is needed for the transfer of antherozoids to the
mouth of archegonium.
● Antherozoid fuses with the egg in the archegonium to
form zygote.
● Zygote develops to a multicellular well differentiated
sporophyte.
● Most pteridophytes produce similar kinds of
spores(homo-

39. sporous plants).
● Others produce two kinds of spores macro(mega) &
microspores and are called as heterosporous.
● The spores germinate and give rise to female and male
gametophytes.
● Within female gametophyte, zygote develop into young
embryos . This event is a precursor to the seed habit and is
considered as an important step in evolution.
● Is divided into four. They are :

40. (i) Psilopsida
(ii) Lycopsida
(iii) Sphenopsida
(iv) Pteropsida
● Examples:- Selanginella and Salvinia

42. GYMNOSPERMS

43. ● Ovules are not enclosed by ovary wall.
● Seeds that develop post-fertilization are not covered.
● Include medium sized trees or tall trees or shrubs.
● Sequoia (giant redwood)is the tallest tree species.
● Roots are generally tap roots.
● Roots in some have fungal association in the form of
mycorrhiza.
● Roots in some have small specialised roots with Nitrogen
fixing cyanobacteria.
● Stems are branched or unbranched.

44. ● Leaves are simple or compound.
● Leaves are well-adapted to withstand extreme
temperature, humidity and wind.
● Pinnate leaves persist for a few years.
● The needle like leaves reduce the surface area.
● The sunken stomata and the thick cuticle of the needle
like leaves help to reduce water loss.
● Heterosporous- produce haploid microspores and
megaspores.
● Some leaves are modified into sporophylls.

45. ● Sporophylls bear sporangia in which spores are
produced.
● Sporophylls are of two types. They are :
(i) microsporophylls
(ii)megasporophylls
● Male and female cones may be born on the same or
different trees.
● Male and female gametophytes do not have an
independent free-living existence.

46. carried by air currents and meet the opening the ovules.
● After fertilization, zygote develops into an embryo and the
ovules into seeds.
(i) Microsporophylls:-
● Arranged to male strobili.
● Bear microsporangia.
● Microspores develop into male gametophyte called pollen
grains.
● Pollen grains are developed within the microsporangia.

47. (ii) Megasporophylls:-
● Arranged to female strobili.
● Bear megasporangia.
● Mainly consist of a body called nucellus, protected by
envelops.
● Megaspore mother cell is differentiated from a cell of the
nucellus.
● Mother cell undergoes meiosis to form four megaspores.

49. ANGIOSPERMS

50. ● Large group of plants.
● Range from microscopic to tall trees.
● Divided into two. They are dicotyledon and
monocotyledon.
I. Dicotyledon:-
● Have two cotyledon in seeds.
● Have reticulate venation in leaves.
● Tetramerous or pentamerous flowers ( 4 or 5 members in
each floral whorl).
● Have tap roots.

51. II Monocotyledon:-
● Have one cotyledon in seed.
● Parallel venatation in leaves.
● Trimerous flowers (3 members in each floral whorl).
● Fibrous roots.
● Reproductive structure is flower.
● Male sex organ is stamen.

52. ● Stamen consist of filament with an anther at the tip.
● The pollen mother cell divides by meiosis to produce
microspores which matures into pollen grains.
● Female sex organ is pistil.
● Pistil consist of ovary at its base, a long slender style and
stigma.
● Ovary contains ovules.
● Ovule has a megaspore mother cell that undergoes
meiosis to form four haploid megaspores.
● Three of them degenerate and one divides to form embryo
sac.

53. ● Each embryo sac has a three celled egg apparatus(one
egg cell and two synergids), three antipodal cells and two
polar nuclei.
● Polar nuclei fuse to produce a secondary nucleus(2n).
● Pollen grains are dispersed from the anthers and carried
by wind or other agencies to the stigma of a pistil and the
process is called pollination.
● Pollen grains germinate on the stigma and the resulting
pollen tubes grow through the tissues of stigma and style
and reach the ovule.

54. ● Pollen tubes enter the embryo sac where two male
gametes are discharged.One male gamete fuses with egg
cell to form zygote(syngamy).
● Other male fuses with diploid secondary nucleus to
produce triploid primary endosperm nucleus (PEN)
because of the involvement of two fusions, this event is
called double fertilization and is an event unique to
angiosperms.
● Zygote develops into an embryo.
● PEN develops into endosperm which provides
nourishment

55. to the developing embryo.
● Synergids and antipodals degenerate after fertilization.
● Ovules develop into seeds and ovaries develop into fruits.
● Seeds are enclosed by fruits.

57. PLANT LIFE CYCLES AND
ALTERNATION OF
GENERATIONS

58. ● In plants, both haploid and diploid cells can divide by
mitosis. This forms haploid and diploid plant bodies.
● Haploid plant body (gametophyte) produces gamates by
mitosis.
● After fertilization, the zygote also divides by mitosis to
produce diploid plant body(sporophyte). This produces
haploid spores by meiosis.Spores divide by mitosis to
form a haploid plant body.
● Thus, during the life cycle of any sexually reproducing
plants,there is an alternation of generation between
gametophyte and sporophyte.

59. Haplontic
● In this, sporophytic generation is represented only by the
zygote.
● Zygote undergoes meiosis to form haploid spores. They
divide mitotically to form gametophyte.
● The dominant, photosynthetic phase is the free-living
gametophyte.
● Examples:- Algae such as Volvox, Spirogyra, and some
species of Chlamydomonas.

60. Haplontic

61. Diplontic
● In this, the diploid sporophyte is the dominant,
photosynthetic, independent phase.
● Gametophytic phase is represented by the single to few
celled haploid gametophyte.
● Examples:- Algae, Fucus, all seed bearing plants
(gymnosperms and angiosperms - the gametophytic
phase is few to multi-celled).

62. Diplontic

63. Haplo-Diplontic
● It is the intermediate condition between haplontic and
diplontic.
● Both gametophyte and sporophyte are multicellular and
often free living.
● But they have different dominant phases.
● Examples:- Bryophytes and Pteridophytes.

64. Haplo-Diplontic