Test: Pteridophytes - Grade 11 MCQ

The seed habit was established in Gymnosperms. The development of seed habit, seen in present-day gymnosperms (and also in angiosperms) eliminated the requirement of water during sexual reproduction. In seed plants, two types of sporangia develop on sporophylls. They are known as megasporangium (ovule) and microsporangium.  The ovule upon fertilization gives rise to the seed.  

Heterospory is a phenomenon in which two kinds of spores are borne by the same plant. These spores differ in size. The smaller one is known as microspore and the larger one is known as megaspore. The microspore germinates to form the male gametophyte and the megaspore germinates to form the female gametophyte. Heterospory evolved first in pteridophytes such as Selaginella and Salvinia. Hence option B is correct.

Sporophyte characteristic of Psilopsida is rhizoids, some are without leaves and protostele. In Psilopsida, plants have rootless sporophytes. The stem is differentiated into an underground rhizome and an aerial part. Both are dichotomously branched. The rhizome bears rhizoids, both perform the function of a root. The aerial branches are green, leafless and bear small veinless outgrowths and carry out photosynthesis.
So, the correct answer is option D.

In Pteridophyta there is a regular feature of alternation of generations. At the time of sporogenesis the reduction division takes place and the haploid spores are formed, which represent the first stage of the gametophyte generation. Later on fertilization takes place and a zygote is produced, which represents the first stage of sporophyte generation. This way the gametophyte gives rise to the sporophyte by the process of syngamy and the sporophyte gives rise to the gametophyte by the process of meiosis.

Seed plants and mosses, the life cycle of pteridophytes involves alternation of generations. This means that a diploid generation (the sporophyte, which produces spores) is followed by a haploid generation (the gametophyte or prothallus, which produces gametes).

Halophytic algae are typically found in saline sea water and salt lakes. These algae have adapted to withstand high concentrations of salts in their environment, making them capable of surviving and thriving in conditions that would be inhospitable to many other types of organisms.

The significance of mycorrhiza in the roots of some gymnosperms is that it improves nutrient uptake through a symbiotic relationship with fungi. Mycorrhizal fungi colonize the plant roots and extend far into the soil, increasing the surface area for water and nutrient absorption, particularly phosphorus, and in some cases, providing protection against pathogens.

Chlorella is used as a food supplement due to its high protein content. It is a unicellular green alga that has been researched for its nutritional benefits, including being a rich source of vitamins, minerals, and antioxidants, making it a popular supplement in health and wellness circles.

The antherozoid of Lycopodium is pear shaped with two flagella at the anterior end. The biflagellate antherozoids of Lycopodium resemble more to the antherozoids of Bryophytes, rather than those of vascular plants.

The role of gemma cups in liverworts is for asexual reproduction. Gemma cups are specialized structures that contain gemmae, which are small, multicellular reproductive units. When mature, gemmae can be dispersed to new locations, where they can grow into new liverwort plants, facilitating rapid and efficient asexual reproduction.

The sporophyte part of the pteridophyte life cycle is dominant and photosynthetic. In pteridophytes, unlike bryophytes, the sporophyte generation is the larger, more visible stage of the life cycle and is capable of photosynthesis. This marks a significant evolutionary advancement from the bryophytes, where the gametophyte is the dominant life stage.

Carrageenan, obtained from red algae, is used as a pharmaceutical emulsifier and in food industries. It is a type of phycocolloid that has thickening, gelling, and stabilizing properties, making it a valuable additive in various food products, cosmetics, and pharmaceuticals.

The feature unique to the seeds of gymnosperms compared to those of angiosperms is that they are naked, without an ovary. Gymnosperm seeds are exposed on the surface of scales or leaves, or at the end of stalks, and are not enclosed by an ovary, which is a distinguishing characteristic from angiosperms, where seeds are enclosed within a fruit.

In Bryophytes, the main plant body is the gametophyte, which is haploid and produces gametes. This distinguishes them from many other plant groups where the sporophyte is the dominant life stage. Bryophytes are often referred to as "amphibians of the plant kingdom" because they require water for sexual reproduction, highlighting their reliance on the gametophyte stage for reproduction.

Azolla, a water fern, forms a symbiotic association with the nitrogen-fixing cyanobacterium Anabaena azollae. This unique relationship allows Azolla to contribute significantly to the nitrogen content of rice paddies, where it is often used as a biofertilizer, enhancing soil fertility and reducing the need for synthetic fertilizers.

The Phylogenetic classification system is based on evolutionary relationships among organisms. This system assumes that organisms belonging to the same taxa have a common ancestor, making it a more natural and reflective method of classifying life forms compared to artificial systems. Phylogenetic classification helps in understanding the evolutionary history and relationships between different organisms, providing a framework for the study of biodiversity and evolution.

Oscillatoria brevis is known for its ability to survive in hot water springs, with temperatures ranging from 50-70°C. This adaptability is due to its lack of a well-organized nucleus, allowing it to withstand extreme environmental conditions. This characteristic makes Oscillatoria brevis a fascinating subject for studying extremophiles and their

In Bryophytes, the sporophyte does not have a free-living stage. It is dependent on the gametophyte for nutrition and support. This contrasts with other plant groups like Pteridophytes and Gymnosperms, where the sporophyte is the dominant, free-living stage of the life cycle. Bryophytes represent an evolutionary step towards the land plant life cycle, where the sporophyte becomes increasingly independent.

In Fern, the antheridia and archegonia are developed on prothallus. The antherozoid and archegonia fuse to form diploid zygote, which is the beginning of the sporophytic stage. The sporophyte (2n) gives rise to gametophyte (n), i.e., prothallus and again by the process of union of the gametes the sporophytic stage is developed. Thus, it may be said that fern exhibits an alternation of haploid (gametophytic) and diploid (sporophytic) generations. However, unlike Bryophytes, the fern plant is the diploid sporophyte.