Very Short Answer Type Questions

1. What is the basis of classification of Algae?

A: The basis of classification of Algae is

‣ Pigmentation

‣ The type of stored food

‣ Cell wall materials

2. When and where does the reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?

A: Liverwort: It is a primitive bryophyte. Reduction division occurs in the spore mother cells, inside capsule.

e.g.: Riccia, Marchantia

Moss: It is an advanced bryophyte. Reduction division occurs in the the spore mothers of capsule.

e.g.: Funaria (Cord Moss), Polytrichum (Hair cap Moss), Sphagnum (Peat Moss).

Ferns: They belong to Pteropsida in Pteridophytes. They are 2 types.

1) Homosporous.        e.g.: Pteris

Reduction division occurs in spore mother cells of sporangium.

2) Heterosporous       e.g.: Azolla, Marisilea

Reduction division occurs in Microspore mother cells (microsporangium) and Megaspore mother cells (Megasporangium).

Gymnosperm: All are heterosporous

Reduction division occurs in microspore mother cells of microsporangium and megaspore mother cell of Ovule. e.g.: Cycas, Pinus, Ginkgo, Gnetum.

Angiosperms: All are heterosporous.

Microspore mother cells of the anther and megaspore mother cell of the Ovule show reduction division.

3. Differentiate between Syngamy and triple fusion.

A:

4. Differentiate antheridium and archegonium.

A:

5. What are the 2 stages found in the gametophyte of mosses?

Mention the structures from which these 2 stages develop.

A: There are 2 stages in the gametophyte of mosses

1) Juvenile stage called Protonema

2) Leafy stage called Gametophore

Protonema is produced from spore.

Gametophore is produced from lateral adventitious bud of protonema.

6. Name the stored food materials found in Phaeophyceae and Rhodophyceae.

A: Phaeophyceae - Mannitol, Laminarin

Rhodophyceae - Floridian starch

7. Name the pigments responsible for brown colour of Phaeophyceae and red colour of Rhodophyceae.

A: Brown colour of Phaeophyceae - Xanthophyll called Fucoxanthin

8. Name different methods of Vegetative reproduction in Bryophytes.

A: Liverworts (Marchantia): Vegetative reproduction occurs by gemmae and separation of old branches.

Mosses (Funaria etc): Vegetative reproduction occurs by tubers, gemmae and secondary protonema.

9. Name the integumented megasporangium found in Gymnosperms. How many female gametophytes are generally formed inside the megasporangium?

A: The integumented megasporangium in Gymnosperm is called Ovule. Only one female gametophyte is formed generally inside the megasporangium.

10. Name the Gymnosperms which contain Mycorrhiza and Coralloid roots respectively?

A: Pinus and Cycas show Mycorrhiza and coralloid roots respectively. They are meant for N2 fixation.

11. Mention the ploidy of the following.

a) Protonemal cell of a moss - n

b) Primary Endosperm Nucleus in a dicot - 2n

c) Leaf cell of Moss - n

d) Prothallus of a Fern - n

e) Gemma cell in Marchantia - n

f) Meristem of a monocot - 2n

g) Ovum of a liverwort - n

h) Zygote of a Fern - 2n

12. Name the 4 classes of Pteridophyta with one example each.

A: There are 4 classes. Name of the class ends with - Sida

‣ Psilopsida - e.g.: Psilotum

‣ Lycopsida - e.g.: Lycopodium, Selaginella.

‣ Sphenopsida - e.g.: Equisetum

‣ Pteropsida - e.g.: Azolla, Salvinia, Dryopteris, Pteris, Adiantum and Marsilea.

13. What are the organisms to colonise rocks? Give the generic name of the moss which provides peat?

A: Mosses along with lichens are the first organisms to colonise rocks. Species of sphagnum provides peat.

14. Mention fern characters in Cycas.

A: Cycas shows the following fern characters.

1) Ramenta

2) Mesarch Xylem

3) Circinate Vernation

4) Multiciliated antherozoids

5) Presence of archegonia

15. Why are Bryophytes called the amphibians of Plant Kingdom?

A: They are primitive land plants and depend on water for sexual reproduction. So bryophytes are also called as Amphibians of Plant Kingdom.

16. Give examples for Unicellular alga, Colonial alga, Filamentous alga.

A: Unicellular alga - Chlamydomonas, Chlorella, Acetabularia, Diatoms. Colonial alga - Volvex, Scenedesmus.

Filamentous alga - Spirogyra, Zygnema, Ulothrix, Chara, Ectocarpus Oedogonium.

Some important Short Answer Type Questions

1. Differentiate between Red Algae and Brown Algae.

A:

2. Differentiate between Liverworts and Mosses.

A:

3. What is meant by homosporous and heterosporous Pteridophytes? Give 2 examples.

A: A sporophyte which produces only one type of spores is called homosporous.

e.g.: Lycopodium, Equisetum, Pteris A sporophyte which produces two kinds of spores (differ in size structure and function) is called heterosporous.

e.g.: Selaginella, Marsilea, Salvinia.

4. What is heterospory? Briefly comment on its significance. Give two examples.

A: A sporophyte which produces 2 kinds of spores which differ in (1) Number (2) size (3) structure and (4) function is called heterosporous. This phenomenon is called heterospory. It is the first step in the formation of seed habit.

e.g.: Selaginella, Salvinia, Marsilea.
 

Exercises

1. How far does Selaginella, one of the few living members of Lycopodiales (Pteridophytes) fall short of seed habit?

A: There are three steps to seed habit.

1) Heterospory

2) Reduction in the number of megaspores

3) Retention of female gametophyte (precursor to seed habit)

The first 2 conditions are full filled in Selaginella. Zygote develops into embryo inside the female gametophyte if it is completely retained by the sporophyte. But in Selaginella after fertilisation, female gametophyte falls on the ground at 13 - celled stage of the embryo (incomplete retention).

2. Each plant or group of plants has some phylogenetic significance in relation to evolution. Cycas, one of the few living members of Gymnosperms is called as the 'retic of the past'. Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement?

A: Cycas is a member of gymnosperms, the first seed bearing flowering plants.

Though these are advanced they still show characters of ferns. So we call Cycas as retic of the past. The fern characters in Cycas are

1) Circinate vernation

2) Presence of ramenta

3) Presence of antheredial cells

4) Presence of archegonia

5) Multiciliated antherozoids

6) Zoidogamous Oogamy

7) Presence of Multi-Cellular female gametophyte.

8) Mesarch Xylem. Thus Cycas shows Phylogenetic relationship with a group of Pteridophytes (Ferns). Then Cycas can be rightly called as "a retic of the past".

3. The male and female reproductive organs of several Pteridophytes and Gymnosperms are comparable to floral structures of angiosperms. Make an attempt to compare the various reproductive parts of Pteridophytes and Gymnosperms with reproductive structures of Angiosperms.

A: The heterosporous Pteridophytes and gymnosperms bear common reproductive structures comparable to the reproductive structures of Angiosperms