Free Biodiversity and Variety of Life MCQs with Answers

1691. Which of the following is responsible for peat formation?

• A. Marchantia
• B. Riccia
• C. Funaria
• D. Sphagnum

Explanation: (d) : Among the bryophytes Sphagnum accounts by far the most important place economically. It is popularly called bog moss or peat moss. It is perennial and its growth continues year after year. Older portions undergo death but do not decompose due to secretion of acid that accounts for the antibacterial and antifungal actions. The increasing mass of dead remains accumulate year after year and form a compact dark coloured mass rich in carbon which is called peat. Peat is used as fuels. Paraffin, acetic acid, peat tar and ammonia are formed as by­products of peat obtained for industrial uses

1692. Male gametophyte with the least number of cells is present in:

• A. Pteris
• B. Funaria
• C. Lilium
• D. Pinus

Explanation: Lilium is an angiosperm plant, in which male gametophyte is 3 - celled and most reduced gametophyte as compared to Funaria (bryophyte). Option C is right.

1693. Isogamous condition with non­-flagellated gamete is found in:

• A. Volvox
• B. Fucus
• C. Chlamydomonas
• D. Spirogyra

Explanation: (d) : Chlamydomonas hasflagellated gametes which are similar or dissimilar in size. In Volvox and Fucus, non­motile female gametes and motile male gametes are produced (oogamy). Spirogyra has gametes that aresimilar in size (isogamous) and are non­flagellated.

1694. Monoecious plant of Chara shows occurrence of:

• A. Upper antheridium and lower oogonium on the same plant
• B. Upper oogonium and lower antheridium on the same plant
• C. Antheridiophore and archegoniophore on the same plant
• D. Stamen and carpel on the same plant

Explanation: (B) : All species of Chara reproduce sexually and show highly advanced oogamy. The sex organs are the most distinctive features of the Order Charales and are the most complicated among the thallophytes. Male and female gametangia are called antheridia and oogonia respectively. Male fructification (cluster of antheridia) is called globule and the female is nucule. They are borne at the nodes of short branches, globule towards lower side and nucule (female structure) towards upper side

1695. Syngamy can occur outside the body of the organism in:

• A. Mosses
• B. Algae
• C. Ferns
• D. Fungi

Explanation: (b) : Syngamy is the complete and permanent fusion of male and female gametes to form the zygote. When fertilization occurs outside the body of the organism, this type of gametic fusion is called external fertilization or external syngamy. In majority of algae, external fertilization occurs.

1696. What is common in all the three Funaria, Dryopteris, and Ginkgo?

• A. Presence of archegonia
• B. Well developed vascular tissues
• C. Independent gametophyte
• D. Independent sporophyte

Explanation: (a ) : In Funaria ( Bryophyta), Dryopteris is (Pteridophyta) and Ginkgo (Gymnosperm) female sex organ ar archegonium is formed. Funarilacks independent sporophyte and vascular tissues while independent gametophyte is absent in Ginkgo.

1697. The plant body is thalloid in:

• A. Sphagnum
• B. Salvinia
• C. Marchantia
• D. Funaria

Explanation: (c) : Sphagnum and Funaria belong to Class Bryopsida of Division Bryophyta. They are typically mosses. The plant body has radial symmetry and is essentially leafy. Salvinia belongs to division Pteridophyta. It has a sporophyte plant body with true leaves, stem, and roots. Marchantia belongs to Class Hepaticopsida of Division Bryophyta. They are also called liverworts. The plant body is a dorsoventrally flattened thallus.

1698. Which one of the following is a correct statement?

• A. Pteridophyte gametophyte has a protonemal and leafy stage
• B. In gymnosperms, female gametophyte is free­living
• C. Antheridiophores and archegoniophores are present in pteridophytes
• D. Origin of seed habit can be traced in pteridophytes

Explanation: (d) : In the majority of the pteridophytes all the spores are of similar kinds ; such plants a recalled homosporous. Genera likeSelaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores, are known as heterosporous.The megaspores and microspores germinate and give rise to female and male gametophytes, respectively. The female gametophytes in these plants are retained on the parent sporophytes for variable periods. The development of the zygotes into young embryos takes place within the female gametophytes. This event is a precursor to the seed habit considered an important step in evolution.

1699. Cycas and Adiantum resemble each other in having:

• A. Seeds
• B. Motile sperms
• C. Cambium
• D. Vessels

Explanation: (b) : Cycas is a gymnosperm and Adiantum is a pteridophyte. Cambium and seeds are absent in pteridophytes, while vessels are absent in both of these two groups. Both Cycas andAdiantum resemble each other in having multi­ciliated sperms.

1700. Read the following five statements (A ­ E) and answer as asked next to them. (A) In Equisetum, the female gametophyte is retained on the parent sporophyte. (B) In Ginkgo, the male gametophyte is not independent. (C) The sporophyte in Riccia is more developed than that in Polytrichum. (D) Sexual reproduction in Volvox is isogamous. (E) The spores of slime molds lack cell walls. How many of the above statements are correct?

• A. Two
• B. Three
• C. Four
• D. One

Explanation: (d ) : Equisetum is a pteridophyte and in pteridophytes, the main plant body is sporophyte which is differentiated into true root, stem, and leaves. Gametophytes are small or inconspicuous and free-living, mostly photosynthetic thalloid called prothallus. Ricciais a liverwort and Polytrichum is a moss. The sporophyte in mosses is more elaborate than that in liverworts. Volvox shows monogamous type of sexual reproduction, i.e., a fusion between one large, non-motile (static) female gamete and a smaller, motile male gamete. During unfavorable conditions, the slime mold differentiates and forms fruiting bodies bearing spores at their tips. The spores possess true walls. They are extremely resistant and survive for many years, even under adverse conditions.