Free Kingdom Plantae MCQs with Answers

41. Diversification in plant life appeared

• A. Due to long periods of evolutionary changes
• B. Due to abrupt mutations
• C. Suddenly on earth
• D. By seed dispersal.

Explanation: a. Diversification in plant life appeared due to long periods of evolutionary changes. Algae and bryophyt es have thalloi d plant body w it h n o differentiation into root, stem and leaves. They had no vascular tissues but later in pteridophytes vascular tissues (xylem and phloem) developed and plant body became differentiated into root, stem and leaves. But the vascular tissues lack vessels and companion cells and they reproduce by spores. In gymnosperms seed habit developed but the seeds are not enclosed inside fruit. In angiosperms vessels and companion cells are present, flowers are present and seeds are enclosed inside fruits. Thus the path of evolution is from algae to bryophytes to pteridophytes to gymnosperms and finally to angiosperm. Plant diversification primarily occurred over long periods of evolutionary changes through a process called natural selection. This process involves the gradual accumulation of genetic variations within plant populations, leading to the emergence of new species over time. Different environmental pressures and adaptations to various ecological niches contribute to the vast diversity of plant life we observe today. The other options are less accurate: b. Due to abrupt mutations: While mutations can introduce new genetic variation, the process of diversification typically involves more than just mutations. It requires the selection and propagation of favorable traits over time. c. Suddenly on earth: Plant diversification did not happen suddenly but evolved gradually over millions of years. d. By seed dispersal: Seed dispersal is a mechanism by which plants can colonize new areas, but it is not the primary driver of diversification. Diversification is a result of evolutionary processes acting on populations over extended periods.

42. Angiosperms have dominated the land flora primarily because of their

• A. Power of adaptability in diverse habitat
• B. Property of producing large number of seeds
• C. Nature of self pollination
• D. Domestication by man

Explanation: Angiosperms have dominated the land flora primarily because of their Power of adaptability in diverse habitats. Angiosperms, or flowering plants, are the most diverse and widespread group of land plants on Earth. Their ability to adapt to a wide range of ecological niches and habitats has contributed significantly to their dominance. Angiosperms have evolved various reproductive strategies, have diversified into many forms, and can grow in various environments, from deserts to rainforests. This adaptability has allowed them to thrive and dominate the plant kingdom. While angiosperms do produce a large number of seeds, the primary reason for their dominance is their adaptability. Self-pollination and domestication by humans are not the main factors behind their dominance in the wild. Other options are explained below: Property of producing a large number of seeds: Angiosperms are known for their efficient seed production. The development of flowers and fruits, often with protective structures, facilitates the production and dispersal of seeds. This reproductive strategy contributes to the widespread distribution of angiosperms. Nature of self-pollination: Some angiosperms are capable of self-pollination, where pollen from the same flower or plant fertilizes the ovules. While self-pollination can ensure reproductive success in certain conditions, it may limit genetic diversity. Domestication by man: Humans have actively cultivated and domesticated many angiosperms for various purposes such as food, medicine, and ornamental purposes. The process of domestication has further contributed to the prevalence and success of angiosperms.

43. Which one of the following pairs of plants are not seed producers?

• A. Fern and Funaria
• B. Funaria and Ficus
• C. Ficus and Chlamydomonas
• D. Funaria and Pinus

Explanation: a.Seed-producing plants belong to Spermatophyta It includes gymnosperms and angiosperms. Seed habit or seed formation originated in gymnosperms. It requires the retention of megasporangium or the only on the parent plant and non-shedding of megaspore, development of integument and in site formation of the female gametophyte. All these features developed in gymnosperms and angiosperms. Thallophyt es, bryophytes, and pteridophytes lack these features and thus do not reproduce by producing seeds. Fern and Funaria belong to pteridophytes and bryophytes respectively so they do not reproduce by producing seeds. Ferns are seedless vascular plants, while Funaria is a non-vascular plant (a moss), and both do not produce seeds. b. Funaria is a non-vascular plant (moss) and does not produce seeds, while Ficus is an angiosperm and produces seeds. c. Chlamydomonas is a green alga and does not produce seeds, while Ficus is an angiosperm and produces seeds. d. Funaria is a non-vascular plant (moss) and does not produce seeds, while Pinus is a gymnosperm and produces seeds.

44. Sexual reproduction in Spirogyra is an advanced feature because it shows

• A. Different sizes of motile sex organs
• B. Same size of motile sex organs
• C. Morphologically different sex organs
• D. Physiologically differentiated sex organs.

Explanation: d. Sexual reproduction in Spirogyra is considered an advanced feature because it shows morphologically different sex organs. Spirogyra is a type of filamentous green alga that exhibits a well-defined sexual reproduction process involving male and female gametangia, which are morphologically distinct structures. The male gametangium (antheridium) produces non-motile male gametes, while the female gametangium (oogonium) produces non-motile eggs. This morphological differentiation is a more advanced form of sexual reproduction compared to species with isogamous gametes or less distinct sexual structures( correct option).Other options are explained below:a. Different sizes of motile sex organs:This option suggests the presence of different-sized motile sex organs in Spirogyra. However, Spirogyra exhibits isogamy, where the male and female gametes are of the same size. Additionally, Spirogyra does not have motile sex organs; instead, the isogametes are released into the water for fertilization.b. Same size of motile sex organs: This option is more accurate than the first one. Spirogyra's isogametes are indeed of the same size. However, it's important to note that Spirogyra lacks motile sex organs. The isogametes are released into the water and move passively to find each other for fertilization.c. Morphologically different sex organs: This option suggests the presence of morphologically different sex organs in Spirogyra. However, Spirogyra exhibits isogamy, where the male and female gametes are morphologically similar. The absence of morphological differences is a characteristic feature of isogamous reproduction.In summary, Spirogyra's sexual reproduction is characterized by isogamy, where the gametes are of the same size and lack morphological and physiological differentiation. Additionally, Spirogyra does not have motile sex organs; instead, the isogametes rely on water currents for fertilization.

45. Plants reproducing by spores such as mosses and ferns are grouped under the general term

• A. Cryptogams
• B. Bryophytes
• C. Sporophytes
• D. Thallophytes

Explanation: a. Plants that reproduce by spores, such as mosses and ferns, are grouped under the general term "Cryptogams." Cryptogams refer to a diverse group of non-seed plants, including bryophytes (mosses and liverworts) and pteridophytes (ferns and their relatives), that reproduce via spores and do not produce seeds. This term is used to categorize plants that don't have the reproductive structures associated with seed-bearing plants (phanerogams). Other options are explained below: b. Bryophytes: This term specifically refers to non-vascular plants, including mosses, liverworts, and hornworts. Bryophytes reproduce through spores, and they lack true vascular tissues. c. Sporophytes: This term refers to the diploid, spore-producing phase in the life cycle of plants that undergo alternation of generations. It's a broader term that includes both vascular and non-vascular plants. d. Thallophytes: This term historically referred to a group of plants with a thallus-like structure, including algae, fungi, and lichens. However, it's not commonly used in modern classifications.

46. Which one pair of examples will correctly represent the grouping Spermatophyta according to one of the schemes of classifying plants?

• A. Acacia, sugarcane
• B. Pinus, Cycas
• C. Rhizopus, Triticum
• D. Ginkgo, Pisum

Explanation: d. Spermatophyta includes seed-bearing plants and this includes gymnosperms and angiosperms. Acacia and sugarcane both are angiosperms. Pinus and Cycas both are gymnosperms. Rhizopus belongs to Kingdom Fungi and Triticum is an angiosperm. Ginkgo is gymnosperm and Pisum is an angiosperm. So Ginkgo and Pisum correctly represent the grouping Spermatophyta. The correct pair of examples that represents the grouping Spermatophyta (seed-producing plants) according to one of the schemes of classifying plants is: Ginkgo and Pisum Spermatophyta includes a wide range of seed-producing plants, including gymnosperms (like Ginkgo) and angiosperms (like Pisum, which is the garden pea). These examples correctly represent the Spermatophyta group. Other options are explained below: a. Acacia, Sugarcane: Acacia: A flowering plant (angiosperm), Sugarcane: Another flowering plant (angiosperm). b. Pinus, Cycas: Pinus (Pine): A gymnosperm with needle-like leaves, Cycas: Another gymnosperm with palm-like leaves. c. Rhizopus, Triticum: Rhizopus: A fungus, Triticum (Wheat): A flowering plant (angiosperm).

47. Which of the following is without exception in angiosperms?

• A. Presence of vessels
• B. Double fertilization
• C. Secondary growth
• D. Autotrophic nutrition

Explanation: b. Double fertilization is without exception in angiosperms. Double fertilization is a unique and characteristic feature of angiosperms (flowering plants) in which two fertilization events occur during the process of sexual reproduction. One sperm cell fertilizes the egg cell to form the zygote, while another sperm cell combines with two polar nuclei to form the triploid endosperm. This results in the development of both the embryo and the endosperm within the seed. Double fertilization is a defining feature of angiosperms and distinguishes them from other plant groups. Other options are explained below: a. Presence of vessels: Angiosperms indeed have vessels, which are specialized water-conducting cells found in their xylem. This is a characteristic feature distinguishing them from gymnosperms and other plant groups. b. Secondary growth: Angiosperms can undergo secondary growth, allowing them to increase in girth over time. This is achieved through the activity of lateral meristems, particularly the vascular cambium and cork cambium. c. Autotrophic nutrition: Angiosperms, like all plants, exhibit autotrophic nutrition. They produce their own food through photosynthesis, utilizing sunlight, water, and carbon dioxide to synthesize organic compounds.

48. Cycas has two cotyledons but not included in angiosperms because of

• A. Naked ovules
• B. Seems like monocot
• C. Circinate ptyxis
• D. Compound leaves.

Explanation: a. Cycas is not included in angiosperms primarily due to "naked ovules." Angiosperms, or flowering plants, are characterized by enclosed ovules within an ovary, which eventually develop into fruits after fertilization. In contrast, Cycas, like other gymnosperms, has naked ovules, meaning that the ovules are not enclosed in an ovary and are typically exposed on the surface of cone scales. This is one of the key differences between angiosperms and gymnosperms. The other options, such as "seems like monocot," "circinate ptyxis," and "compound leaves," are not the primary reasons for the exclusion of Cycas from angiosperms. Naked ovules are the key feature distinguishing gymnosperms, including Cycas, from angiosperms. Other options are explained below: b. Seems like monocot: Cycas, like many gymnosperms, may appear superficially similar to monocots, which are a type of angiosperm. However, the overall reproductive structures and life cycle are different between these groups. c. Circinate ptyxis: Cycas exhibits circinate ptyxis, a type of leaf development where the young leaves are tightly coiled in a circinal manner. This is a characteristic feature of many gymnosperms, including Cycas. d. Compound leaves: Cycas typically has compound leaves, which means the leaf is divided into multiple leaflets. While some angiosperms also have compound leaves, this feature alone is not sufficient to include Cycas among angiosperms.

49. A student observed an algae with chlorophyll a, b and phycoerythrin, it should belong to

• A. Phaeophyta
• B. Rhodophyta
• C. Chlorophyta
• D. Bacillariophyta

Explanation: (b) : The algal Class Rhodophyceae contains a red pigment (r­phycocrythrin) and a blue pigment (r­phycocynin) in the chromatphores. These pigments can utilize those wavelengths of light (blue­green region of spectrum, i.e., 480­520 nm) that are not absorbed by chlorophyll. This enables red algae to grow at greater depths than other plants (upto 300ft. below water). In addition to these, chl.­a, chl.­ d, carotenes and xanthophylls are present. The student likely observed an alga belonging to Rhodophyta. Rhodophyta, commonly known as red algae, are characterized by the presence of chlorophyll a and chlorophyll d, chlorophyll b, and the red pigment phycoerythrin. The combination of these pigments gives red algae their characteristic reddish color. Among the options provided, only Rhodophyta fits this description. In phaeophyceae chromatophores are yellowish brown in colour possessing xanthophylls in abundance. Bacillariophyceae are called 'diatoms' due to presence of an accessory brown pigment called 'diatomin', other pigments are chl.-a, chl-­c (but not chl.-b), carotenes and xanthophylls. In chlorophyceae colouring pigments are just like higher plants, i.e., Chl.-a, Chl.-b, xanthophylls and carotenes.

50. In ferns, meiosis takes place at the time of

• A. Spore formation
• B. Spore germination
• C. Gamete formation
• D. Antheridia and archegonia formation.

Explanation: (a) : A fern plant body is sporophytic (2n) and is differentiated into roots, stems, and leaves. On the ventral surface of leaves, sporangia are borne in a group called sori. Inside the sporangium are present the spores which are formed by reduction division. Thus the spores produced are haploid in nature and germinate to produce a prothallus that represents the gametophytic generation. Antheridium and archegonium are borne on this prothallus. Thus meiosis takes place at the stage of spore formation.