Life cycle with zygotic
meiosis
Life cycle with
gametic meiosis
(i) Zygote is the only diploid
structure in the life cycle.
All structures except
gametes are diploid.
(ii) The dominant individual
in the life cycle is haploid
hence the life cycle is
haplontic.
The dominant individual
in the life cycle is diploid
hence the life cycle is
diplontic.
(iii) Meiosis takes place at the
time of zygote germination.
Meiosis occurs only at the
time of gamete formation.
- (a) The given figure is of Euglena. Here, A is Cytostome, B
is Stigma, C is Paramylum bodies and D is Chloroplast.
(b) The cytostome (A) is an eccentric mouth part at the
apical end of the organism. It leads to a tubular canal,
called cytopharynx which expands at the base to form a
large rounded reservoir. At the end of the reservoir, the
cytoplasm contains an orange red stigma or eye spot. It
is photosensitive. It contains red pigment astaxanthin.
Paraflagellar body and eye spot together help in directing
the organism towards the optimum light.
(c) The nutrition in Euglena, is holophytic (photoautotrophic)
or (saprobic). When it is allowed to grow in dark, the
photosynthetic form can feed on organic remains. Such
mode of nutrition is known as mixotrophic.
CHAPTER-3: PLANT KINGDOM
- (d) 2. (c) 3. (c) 4. (b) 5. (c)
- (b) 7. (b) 8. (d) 9. (b) 10. (a)
- (a) 12. (d) 13. (b) 14. (a) 15. (a)
- A-(iii); B-(v); C-(iv); D-(i); E-(ii)
- A-(i, vi), B-(iii, vii), C-(ii, iv), D-(v, viii), E-(ix, x)
18.(A)(i) Batrachospermum (ii) phycoerythrin
(iii) blue-green (iv) chromatophores
(v) floridean starch (vi) glycogen
(vii) spores (viii) oogamous
(ix) antheridium (x) carpogonium
(B) Ferns are seed producing seedless vascular plants which
inhabit dry humid areas. They constitute the smallest
largest living group of primitive vascular plants. Ferns
dominated the earth in permian carboniferous period.
Leaves are large and called ramenta fronds. Mature Young
leaves show circinate ptyxis. Younger parts of their stem,
leaves and petiole possess hairs called fronds ramenta.
- (a) 20. (c) 21. (d) 22. (b) 23. (a)
- (b) 25. (b) 26. (d) 27. (a) 28. (c)
- (a) The given figures A and B represent Marchantia
(Division Bryophyta) and Selaginella (Division Pteridophyta)
respectively.
(b) Plant A, Marchantia belongs to plant group bryophytes.
Bryophytes are called amphibians of Plant Kingdom as
they require an external layer of water on the soil surface
for their existence. The external water is required for : (i)
dehiscence of antheridia and archegonia (ii) swimming
of male gametes to archegonia, (iii) protection from
transpiration and hence desiccation as the plant body is
not covered by cuticle (iv) supply of water to all parts
through capillarity as vascular tissues are absent in them.
(c) The economic importance of pteridophytes (B) is as follows:
(i) Pteridophytes constitute a good source of food to animals.
For example, sporocarps of Marsilea, yield starch that is
cooked and eaten by certain tribal people. (ii) Pteridophytes
bind the soil even along hill slopes and thus protect the
soil from erosion. (iii) Equisetum stems have been used in
scouring i.e., cleaning of utensils and polishing of metals.
(iv) Azolla has a symbiotic association with nitrogen
fixing cyanobacterium Anabaena azollae. (v) An anti-
helminthic drug is obtained from rhizomes of Dryopteris.
(vi) Ferns are grown as ornamental plants for their delicate
and graceful leaves.
- (a) The life cycle in the given figure is of diplontic type. A
is the sporophytic generation while B is the gametophytic
generation. (Sporophytic part is elaborate and major
whereas haploid part is only confined to gametes).
(b) Fucus and Sargassum show diplontic life cycle.
(c) The diplontic life history in fucales such as Fucus and
Sargassum, is clearly derived from a diplo-haplontic life
cycle where the gametophytic or haploid somatic phase
gets eliminated through progressive evolution.
CHAPTER - 4 : ANIMAL KINGDOM
- (b) 2. (b) 3. (b) 4. (d) 5. (b)
- (c) 7. (a) 8. (b) 9. (d) 10. (d)
- (b) 12. (b) 13. (c) 14. (a) 15. (d)
- A-(iii); B-(iv); C-(i); D-(v); E-(ii)
- A-(i, vi); B-(ii, v); C-(iii,vii); D-(iv,ix); E-(viii, x)
18.(A) (i) eucoelomate or coelomate (vi) echinoderms
(ii) embryonic mesoderm (vii) chordates
(iii) peritoneum (viii) schizocoelom
(iv) coelomic fluid (ix) enterocoelom
(v) annelids (x) acoelomates
(B) Amphibians are warm cold blooded animals. Their skull
is monocondylic dicondylic and the heart is two three
chambered. Kidneys are metanephric mesonephric and
urinary bladder is absent present in frog. Their larval forms
are ureotelic ammonotelic whereas adults are ammonotelic
ureotelic. Twelve Ten pairs of cranial nerves are present in
