Question:

Describe the important characteristics of gymnosperms?

Answer:

1. Gymnosperms are a group of seed-producing plants that includes conifers, cycads, ginkgo, and gnetophytes.

2. Gymnosperms have naked seeds, meaning that the seeds are not enclosed in an ovary or fruit.

3. Gymnosperms are vascular plants, meaning they have specialized tissues for conducting water and nutrients throughout the plant.

4. Gymnosperms have woody stems and leaves that are typically needle-like or scale-like.

5. Gymnosperms are usually evergreen, meaning they retain their leaves year-round.

6. Gymnosperms typically reproduce through the production of cones, which contain the male and female reproductive structures.

7. Gymnosperms are an important source of timber and often used in landscaping due to their attractive foliage.

Question:

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

Answer:

Liverwort: Reduction division takes place during the sporophyte stage.

Moss: Reduction division takes place during the gametophyte stage.

Fern: Reduction division takes place during the sporophyte stage.

Gymnosperm: Reduction division takes place during the gametophyte stage.

Angiosperm: Reduction division takes place during the sporophyte stage.

Question:

Differentiate between the following: (i) Red algae and brown algae (ii) Liverworts and moss (iii) Homosporous and heterosporous pteridophyte (iv) Syngamy and triple fusion

Answer:

(i) Red algae are multicellular, while brown algae are mostly multicellular but some species can be unicellular. Red algae are mostly found in tropical and subtropical waters, while brown algae are found in cold and temperate waters.

(ii) Liverworts are non-vascular, while mosses are vascular. Liverworts have a flattened, ribbon-like body, while mosses have a three-dimensional body with stems and leaves.

(iii) Homosporous pteridophytes produce spores of a single size and shape, while heterosporous pteridophytes produce spores of two different sizes and shapes.

(iv) Syngamy is a type of sexual reproduction in which two gametes fuse together, while triple fusion is a type of sexual reproduction in which three gametes fuse together.

Question:

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

Answer:

Answer:

1. Heterospory is the production of two different types of spores by a plant, one of which develops into a male gametophyte and the other into a female gametophyte.

2. The significance of heterospory is that it allows plants to reproduce in a more efficient way, as it ensures that the male and female gametophytes are produced in separate structures and can be easily distributed.

3. Two examples of heterosporous plants are ferns and cycads.

Question:

Both gymnosperms and angiosperms bear seeds, then why are they classified separately?

Answer:

Step 1: Understand the terms ‘gymnosperms’ and ‘angiosperms’.

Step 2: Research the differences between gymnosperms and angiosperms.

Step 3: Analyze the evidence for why the two types of plants are classified separately.

Step 4: Draw a conclusion based on the evidence.

Question:

Explain briefly the following terms with suitable examples : (i) Protonema (ii) Antheridium (iii) Archegonium (iv) Diplontic (v) Sporophyll (vi) Isogamy

Answer:

(i) Protonema: Protonema is a filamentous green algal structure that is formed after the germination of a spore. It is the first stage of the life cycle of a moss. Example: The protonema of the moss Physcomitrella patens.

(ii) Antheridium: An antheridium is a reproductive organ found in male plants, such as mosses and ferns, that produces sperm cells. Example: The antheridium of the moss Funaria hygrometrica.

(iii) Archegonium: An archegonium is a female reproductive organ found in plants, such as mosses and ferns, that produces egg cells. Example: The archegonium of the moss Funaria hygrometrica.

(iv) Diplontic: Diplontic is a type of life cycle in which the sporophyte generation is dominant and the gametophyte generation is reduced and dependent on the sporophyte. Example: The life cycle of most vascular plants, including ferns and angiosperms.

(v) Sporophyll: A sporophyll is a leaf-like structure that produces spores in plants. Example: The sporophylls of the fern Asplenium nidus.

(vi) Isogamy: Isogamy is a type of sexual reproduction in which the gametes are morphologically and functionally similar. Example: Most algae, such as Chlamydomonas, reproduce by isogamy.

Question:

Match the following (column I with column II). Column I Column II (a) Chlamydomonas (i) Moss (b) Cycas (ii) Pteridophyta (c) Selaginella (iii) Algae (d) Sphagnum (iv) Gymnosperm

Answer:

(a) Chlamydomonas (iii) Algae (b) Cycas (iv) Gymnosperm (c) Selaginella (ii) Pteridophyta (d) Sphagnum (i) Moss

Question:

Write a note on economic importance of algae?

Answer:

Step 1: Begin by researching the economic importance of algae. Consider looking at scientific journals, news articles, and other sources of information to gain a better understanding of the topic.

Step 2: Once you have gathered all the necessary information, begin forming an outline of the note. Consider including topics such as the use of algae in food, fuel, and medicine, as well as its role in environmental protection.

Step 3: Draft the note, using the outline as a guide. Make sure to include evidence to support your points and to provide examples where appropriate.

Step 4: Edit the note for clarity and accuracy. Pay attention to grammar, spelling, and other aspects of the writing.

Step 5: Read the note aloud, or have someone else read it, to check for any errors that may have been missed.

Step 6: Once the note is complete, you can publish it or share it with others.

Question:

Mention the ploidy of the following:

1. Protonemal cell of a moss,
2. Primary endosperm nucleus in dicot,
3. Leaf cell of a moss,
4. Prothallus cell of a fern,
5. Gemma cell in Marchantia,
6. Meristem cell of a monocot,
7. Ovum of a liverwort,
8. Zygote of a fern.

Answer:

1. Protonemal cell of a moss: Haploid
2. Primary endosperm nucleus in dicot: Triploid
3. Leaf cell of a moss: Haploid
4. Prothallus cell of a fern: Haploid
5. Gemma cell in Marchantia: Diploid
6. Meristem cell of a monocot: Haploid
7. Ovum of a liverwort: Diploid
8. Zygote of a fern: Diploid

Question:

Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them?

Answer:

1. Three groups of plants that bear archegonia are mosses, liverworts, and ferns.

2. The life cycle of a fern, for example, begins with a spore, which is a single-celled reproductive unit. The spore germinates and grows into a tiny, heart-shaped structure called a prothallus. The prothallus produces both male and female reproductive structures, which are the archegonia and antheridia. The archegonia produces egg cells, and the antheridia produces sperm cells. The sperm cells travel to the archegonia and fertilize the egg cells, which then develop into an embryo. The embryo develops into a sporophyte, which is the dominant form of the fern, and the sporophyte produces spores, thus completing the life cycle.

Question:

What is the basis of classification of algae?

Answer:

Answer:

1. Algae are classified based on their pigmentation, size, shape, and type of reproduction.
2. Pigmentation is one of the most important criteria used to classify algae. Algae are divided into two major groups based on their pigmentation: brown algae and green algae.
3. Size is another important factor in the classification of algae. Algae can be classified as microscopic (less than 0.2 mm in diameter) or macroscopic (greater than 0.2 mm in diameter).
4. Shape is also important in the classification of algae. Algae can be classified as filamentous, unicellular, or colonial.
5. The type of reproduction used is also important in the classification of algae. Algae can be classified as either asexual or sexual.

Question:

Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them?

Answer:

1. Three groups of plants that bear archegonia are mosses, liverworts, and ferns.

2. The life cycle of a fern, for example, consists of two distinct phases: the haploid phase (gametophyte) and the diploid phase (sporophyte). In the haploid phase, the fern produces haploid gametes (sperm and eggs) in the archegonia and antheridia, respectively. When the sperm and eggs fuse, they form a diploid zygote, which develops into a diploid sporophyte. This sporophyte produces haploid spores in sporangia, which disperse and develop into new haploid gametophytes. The cycle then repeats.