Plant Kingdom - Class 11 Biology - Chapter 3 - Notes, NCERT Solutions & Extra Questions
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Extra Questions - Plant Kingdom | NCERT | Biology | Class 11
The plant body of a bryophyte:
A can be prostrate or erect.
B has true roots, leaves, and a stem.
C has roots for anchorage.
D grows mostly in arid conditions.
The correct answer is A: can be prostrate or erect.
Bryophytes, which are a division of non-vascular plants, typically grow in moist conditions. They have a simple, undifferentiated plant body known as a thallus. This thallus may display different growth forms; it can be either erect (as seen in Funaria) or prostrate (as seen in Marchantia).
The erect form of bryophytes is characterized by a structure differentiated into rhizoids (functioning like roots for anchorage), axis (stems), and leaf-like structures. Despite having these features, they lack the true roots, stems, and leaves found in higher vascular plants.
The science that deals with the study of algae is called
A) mycology
B) herpetology
C) bryology
D) phycology
The correct answer is D) phycology.
Phycology is the branch of science concerned with the study of algae. In contrast:
Mycology involves the study of fungi.
Herpetology focuses on reptiles.
Bryology is dedicated to the study of bryophytes (mosses, liverworts, and hornworts).
Which plant is used to make paper?
A. Papyrus
B. Reed
C. Flax
D. Palm
The correct answer is A. Papyrus.
The Papyrus plant is traditionally used to make paper. In contrast, Reed, Flax, and Palm are primarily utilized for fiber production.
Which famous garden in Bengaluru was established by Hyder Ali?
A) Cubbon Park
B) Lumbini Gardens
C) Lalbagh Botanical Gardens
D) Cariappa Memorial Park
The correct answer is C) Lalbagh Botanical Gardens.
Hyder Ali, a notable figure in expanding the Mysore territory, was not only a courageous soldier but also an adept administrator. One of his lasting contributions includes the establishment of the Lalbagh Botanical Gardens in Bengaluru.
Give the chemical composition of the cell wall in plants and fungi, respectively.
The chemical composition of cell walls differs between plants and fungi:
In higher plants, the cell wall is primarily composed of cellulose, hemicellulose, and pectin. Additionally, substances like lignin and suberin reinforce the cell wall. Calcium and magnesium salts are also integral components of the plant cell wall.
In fungi, the cell wall is mainly made up of chitin, which distinguishes it from plant cell walls that primarily contain cellulose.
Algae belongs to which kingdom out of Protista and Plantae?
Algae can reside in both the Kingdom Protista and Kingdom Plantae, depending on their cellular structure. Specifically, unicellular green algae that are part of the Chlorophyta division are categorized under the Kingdom Protista. In contrast, all multicellular algae, including Green Algae (Chlorophyta), Brown Algae (Phaeophyta), and Red Algae (Rhodophyta), are grouped under the Kingdom Plantae.
Thus, the classification of algae into either kingdom depends essentially on whether they are unicellular or multicellular.
Bamboo is a tree.
A) True
B) False
The correct answer is B) False.
Bamboo is not truly a tree, despite its significant height and tree-like appearance. It actually belongs to the grass family and is considered a tree-like grass scientifically.
35 (e) Write true (T) or false (F): (e) Blue-green algae belong to the kingdom Protista.
Answer: False
Blue-green algae, also known as cyanobacteria, are indeed a diverse group of prokaryotic and primarily photosynthetic organisms. Despite their name, these organisms share similarities with eukaryotic algae in terms of appearance and ecological roles. Historically, due to these similarities, they were classified as algae. However, the realization of their prokaryotic nature has shifted their classification to the kingdom Monera, distinguishing them from Protista. Thus, stating that blue-green algae belong to the kingdom Protista is incorrect.
Money plant is a climber.
A) True
B) False
The correct option is A) True.
The money plant is indeed a climber. It is characterized by a thin, long, and weak stem that cannot stand upright on its own. To grow and extend upwards, it relies on external support. Thus, it qualifies as a climber. Additionally, money plants develop aerial roots that enable them to cling to and climb up supporting structures.
Which of the following organisms has characteristics of both animals and plants?
A. Blue-green algae
B. Euglena
C. Moss
D. Cycas
The correct answer is B. Euglena.
Euglena exhibits characteristics of both animals and plants, making it a unique organism.
The subdivision of Spirogyra is:
A) Algae
B) Fungi
C) Pteridophyta
D) Bryophyta
The correct answer is A) Algae.
Spirogyra falls under the subdivision of Algae, which is a diverse group of photosynthetic organisms found predominantly in aquatic environments.
Phytophthora infestans causes:
A. Wilt in tomato
B. Blight in potato
C. Canker
D. Crown gall
The correct answer is B. Blight in potato.
Phytophthora infestans is notorious for causing the late blight of potato and tomato plants. This pathogen targets the leaves, stems, fruits, and tubers, leading to significant destruction. Phytophthora infestans falls under the class oomycetes, also known as water molds, which were once classified as fungi due to similar characteristics.
Botanical name of Margosa (Neem) is:
A. Azadirachta indica
B. Pisum sativum
C. Cassia fistula
D. Brassica Compestris
The botanical name, also known as the scientific name, of Margosa or Neem is Azadirachta indica. In scientific nomenclature, the name typically consists of two parts:
The first part indicates the genus to which the plant belongs, and
The second part identifies the specific species within that genus.
For Margosa/Neem, the genus is Azadirachta and the species is indica. Thus, the correct botanical name is Azadirachta indica. This classification helps in accurately identifying and categorizing the plant in botanical studies.
Hence, the correct answer is option A: Azadirachta indica.
Association of algae and fungi forms
A Mycorrhiza
B Lichen
C Flower
D Biofertilizer
The question asks about the association of algae and fungi. This combination results in a symbiotic relationship where each organism benefits from the other.
Algae, which are photosynthetic, provide food made from sunlight. On the other hand, fungi, being heterotrophic, absorb water and minerals from the environment. Fungi then supply these vital nutrients to the algae, creating a mutually beneficial relationship. This specific association of algae and fungi is known as a lichen.
Thus, from the given options:
A) Mycorrhiza is incorrect because it involves the association of fungi and plant roots.
C) Flower is incorrect as it does not involve a symbiotic relationship between algae and fungi.
D) Biofertilizer also is incorrect as it typically refers to the use of biological agents and not specifically to the symbiosis between algae and fungi.
Therefore, the correct answer is:
B) Lichen
Amphibians of the plant kingdom are:
A) Bacteria
B) Gymnosperm
C) Bryophyta
D) Algae
Amphibians, such as frogs, are known for their dual lifestyles, living both on land and in water. This term highlights organisms that require two distinct environments to complete different life cycle stages.
In the context of the plant kingdom, Bryophytes (Option C) are often referred to as the "amphibians of the plant kingdom." The reason behind this nickname is their need for both land and water environments to complete their life cycles. Bryophytes typically live on land; however, they crucially depend on water for sexual reproduction. Their sperm are flagellated, which means they are equipped with flagella that help them swim, a process requiring a water medium to reach the egg cells for fertilization.
Thus, similar to amphibians in the animal kingdom who need water for breeding but spend much of their adult life on land, bryophytes also bridge aquatic and terrestrial environments in their reproductive strategy.
Hence, the correct answer to the question "Amphibians of the plant kingdom are" is:
C) Bryophyta
Which plant group is called amphibious plants?
A. Algae
B. Fungi
C. Bryophyta
D. Pteridophyta.
The group of plants referred to as amphibious plants are those which require both land (soil) and water to complete their life cycle. This characteristic makes them analogous to amphibious animals like the frog, which also require both land and water environments.
Among the plant groups, Bryophyta consists of members that require soil for their growth and development but need water especially during reproduction for processes such as fertilization. This dual requirement of both land and water habitat is why Bryophytes are termed as amphibious plants.
Therefore, the correct answer is:
C. Bryophyta.
Other groups such as:
Algae are primarily aquatic and do not require soil.
Fungi and Pteridophyta do not fit the criteria of needing both land and significant amounts of open water for their lifecycle processes.
Thus, option C (Bryophyta) is the accurate choice.
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What is the basis of classification of algae?
The classification of algae is based on the type of pigments they possess and the type of stored food. Specifically, algae are classified into three main classes:
Chlorophyceae (Green Algae): Dominant pigments are chlorophyll a and b.
Phaeophyceae (Brown Algae): Possess chlorophyll a, c, carotenoids, and xanthophylls.
Rhodophyceae (Red Algae): Predominantly have the red pigment r-phycoerythrin along with chlorophyll a and d.
When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?
Reduction Division in Plant Life Cycles
Liverworts:
When and Where: Reduction division (meiosis) occurs within the capsule of the sporophyte to produce haploid spores.
Mosses:
When and Where: Meiosis takes place inside the capsule of the sporophyte to generate haploid spores.
Ferns:
When and Where: Reduction division occurs in the sporangia of the sporophylls resulting in the formation of haploid spores.
Gymnosperms:
When and Where: Meiosis happens in the microsporangia and megasporangia to produce haploid microspores and megaspores.
Angiosperms:
When and Where: Meiosis takes place in the anthers and ovules. In anthers, it results in haploid pollen grains, and in ovules, it results in haploid megaspore cells.
Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.
Groups of Plants that Bear Archegonia
Bryophytes
Pteridophytes
Gymnosperms
Life Cycle of Bryophytes
Bryophytes include various mosses and liverworts. The main plant body of a bryophyte is a gametophyte, which is haploid and produces gametes.
Life Cycle Steps:
Gametophyte Stage:
The gametophyte is the dominant stage.
It bears multicellular sex organs: antheridia (male) and archegonia (female).
The antheridium produces biflagellate antherozoids (sperm).
The archegonium is flask-shaped and produces a single egg.
Fertilization:
The antherozoids are released into water and swim towards the archegonium.
An antherozoid fuses with the egg in the archegonium, forming a zygote.
Sporophyte Stage:
The zygote develops into a multicellular sporophyte.
The sporophyte is attached to the gametophyte and derives its nourishment from it.
The sporophyte undergoes meiosis to produce haploid spores.
Spore Germination:
The haploid spores are released and germinate to form new gametophytes.
The entire lifecycle of bryophytes depends heavily on water for the fertilization process, and the dominant phase is the gametophyte stage.
Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a ferm; gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort, and zygote of a fern.
Protonemal cell of a moss: Haploid (n)
Primary endosperm nucleus in dicot: Triploid (3n)
Leaf cell of a moss: Haploid (n)
Prothallus cell of a fern: Haploid (n)
Gemma cell in Marchantia: Haploid (n)
Meristem cell of a monocot: Diploid (2n)
Ovum of a liverwort: Haploid (n)
Zygote of a fern: Diploid (2n)
These ploidy levels correspond to the various stages and reproductive structures within the life cycles of these plants.
Write a note on economic importance of algae and gymnosperms.
Economic Importance of Algae
Carbon Dioxide Fixation: Algae play a crucial role in the environment by fixing half of the total carbon dioxide on earth through photosynthesis, thereby increasing the level of dissolved oxygen in their surroundings.
Primary Producers: Algae form the foundation of the food cycles of all aquatic animals by producing energy-rich compounds through photosynthesis.
Food Source: Many species of algae are directly used as food. For instance, species such as Porphyra, Laminaria, and Sargassum are edible.
Commercial Products:
Hydrocolloids: Certain marine brown and red algae produce hydrocolloids like algin and carrageen, which are utilized commercially.
Agar: Extracted from Gelidium and Gracilaria, agar is used in microbiological media and food preparations such as ice-creams and jellies.
Food Supplements: Chlorella, a protein-rich unicellular alga, is used as a food supplement, even by space travelers.
Economic Importance of Gymnosperms
Ecological Role: Gymnosperms, such as giant redwood trees, provide essential habitats for numerous animal species, including birds and insects.
Wood Production: These plants are significant sources of timber for construction and paper industries.
Medicinal Uses: Certain gymnosperms have medicinal properties and are used in traditional medicine. For instance, the leaves of Ginkgo biloba are used for their health benefits.
Resins and Oils: Gymnosperms like pines produce resins and essential oils, which have various commercial applications, such as in varnishes, perfumes, and as a raw material for turpentine.
Ornamental Plants: Many gymnosperms are grown as ornamentals for landscape beautification, such as in gardens and parks.
Erosion Control: The extensive root systems of trees like Pinus help in preventing soil erosion on slopes and areas prone to water runoff.
Both gymnosperms and angiosperms bear seeds, then why are they classified separately?
Both gymnosperms and angiosperms bear seeds, but they are classified separately based on key differences in their reproductive structures and processes:
Ovule and Seed Enclosure:
Gymnosperms: The ovules are not enclosed by any ovary wall and remain exposed before and after fertilisation, leading to naked seeds.
Angiosperms: The ovules are enclosed within an ovary. After fertilisation, the ovary develops into a fruit that encloses the seeds.
Reproductive Structures:
Gymnosperms: They have cones (strobili) which contain the reproductive organs. Male cones produce pollen, and female cones contain ovules.
Angiosperms: They have flowers which contain the reproductive organs. The flowers facilitate the development of seeds within fruits.
Thus, the main distinguishing feature is the presence of fruits enclosing seeds in angiosperms, which is absent in gymnosperms, resulting in their separate classification.
What is heterospory? Briefly comment on its significance. Give two examples.
Heterospory refers to the production of two distinct types of spores by the sporophytes of land plants. These two types of spores are:
Microspores: Small spores that germinate to give rise to male gametophytes.
Megaspores: Larger spores that germinate to give rise to female gametophytes.
Significance:
Evolutionary Step towards Seed Habit: Heterospory is considered an important evolutionary advancement as it leads to the development of seeds. Production of seeds is a key factor in the success and diversification of many plant species.
Independent Development: The formation of distinct male and female gametophytes ensures better development and specialization of each gametophyte, contributing to higher reproductive efficiency.
Examples:
Selaginella
Salvinia
These plants exhibit heterospory, showing specialized adaptations that have contributed to their reproductive success.
Explain briefly the following terms with suitable examples:-
(i) protonema
(ii) antheridium
(iii) archegonium
(iv) diplontic
(v) sporophyll
(vi) isogamy
(i) Protonema
Protonema is the first stage of the gametophyte in mosses. It develops directly from a spore and is a creeping, green, branched, and filamentous structure. For example, in *Funaria*, the protonema stage is the initial thread-like chain of cells.
(ii) Antheridium
Antheridium is the male sex organ in bryophytes, pteridophytes, and certain algae. It is often multicellular and produces biflagellate antherozoids (male gametes). For instance, in *Marchantia*, antheridia are produced on the male thalli.
(iii) Archegonium
Archegonium is the female sex organ in bryophytes, pteridophytes, gymnosperms, and some algae. It is flask-shaped and contains a single egg cell. For example, in *Funaria*, the archegonia are present at the tips of the female gametophyte.
(iv) Diplontic
Diplontic refers to a life cycle where the dominant phase is the diploid sporophyte. The gametophytic phase is reduced and short-lived. An example is seen in gymnosperms and angiosperms, where the primary plant body is a sporophyte.
(v) Sporophyll
Sporophylls are leaf-like structures that bear sporangia. In some plants, they may form distinct cones or strobili. For instance, in ferns, sporophylls are the fronds that carry sporangia on their undersides, and in Selaginella, they form compact strobili.
(vi) Isogamy
Isogamy is a type of sexual reproduction involving the fusion of gametes that are morphologically similar. An example is seen in Ulothrix, where the gametes are flagellated and of similar size.
Differentiate between the following:- (in table)
(i) red algae and brown algae
(ii) liverworts and moss
(iii) homosporous and heterosporous pteridophyte
(i) Red Algae and Brown Algae
Feature | Red Algae (Rhodophyceae) | Brown Algae (Phaeophyceae) |
---|---|---|
Common Name | Red Algae | Brown Algae |
Major Pigments | Chlorophyll *a, d*, *r-phycoerythrin* | Chlorophyll *a, c*, *fucoxanthin* |
Stored Food | Floridean starch | Laminarin, Mannitol |
Cell Wall | Cellulose, pectin, and poly sulphate esters | Cellulose and algin |
Flagellar Number and Position of Insertions | Absent | 2, unequal, lateral |
Habitat | Mostly marine (salt water) | Fresh water (rare), brackish water, salt water |
(ii) Liverworts and Moss
Feature | Liverworts | Mosses |
---|---|---|
Plant Body | Thalloid, dorsiventral | Upright, slender axes with spirally arranged leaves |
Habitat | Moist, shady habitats like banks of streams, marshy ground, damp soil, bark of trees | Moist, shaded areas in hills |
Reproduction | Asexual by gemmae, sexual organs on same or different thalli | Vegetative by fragmentation, sex organs at apex of leafy shoots |
Sporophyte | Differentiated into foot, seta, and capsule | More elaborate, containing foot, seta, and capsule |
Example | *Marchantia* | *Funaria*, *Polytrichum*, *Sphagnum* |
(iii) Homosporous and Heterosporous Pteridophytes
Feature | Homosporous Pteridophyte | Heterosporous Pteridophyte |
---|---|---|
Spores | Produce single type of spore | Produce two types of spores: macro (large) and micro (small) spores |
Gametophytes | Spores germinate to give rise to bisexual gametophytes | Macrospores develop into female gametophytes; microspores develop into male gametophytes |
Example | Most pteridophytes | *Selaginella*, *Salvinia* |
Match the following (column I with column II)
Column I | Column II |
---|---|
(a) Chlamydomonas | (i) Moss |
(b) Cycas | (ii) Pteridophyte |
(c) Selaginella | (iii) Algae |
(d) Sphagnum | (iv) Gymnosperm |
Column I | Column II |
---|---|
(a) Chlamydomonas | (iii) Algae |
(b) Cycas | (iv) Gymnosperm |
(c) Selaginella | (ii) Pteridophyte |
(d) Sphagnum | (i) Moss |
Describe the important characteristics of gymnosperms.
Gymnosperms are unique plants characterized by naked seeds, meaning ovules and seeds are exposed, not enclosed in an ovary. They predominantly include medium-sized to tall trees and shrubs. Notable for bearing two kinds of spores: haploid microspores and megaspores, producing microsporangia and megasporangia on sporophylls in groups, forming cones or strobili. Gymnosperms generally exhibit a dominant sporophyte stage, with well-differentiated and vascularised organs like roots, stems, and leaves. Their leaves are specially adapted to conserve water with thick cuticles and sunken stomata. Their reproductive process doesn't require water as pollen is wind-dispersed, an adaptation suitable for diverse environments. These traits make them significantly different from other plant groups.
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Comprehensive Guide to the Plant Kingdom for Class 11 Biology Students
The plant kingdom, also known as Plantae, comprises a diverse array of life forms that play a pivotal role in the ecosystem. From the simplest algae to the most complex angiosperms, this article delves into the classification, characteristics, and significance of different groups within the plant kingdom, which are crucial for Class 11 Biology students.
Introduction to the Plant Kingdom
Overview of the Plant Kingdom
The plant kingdom includes all living organisms that primarily perform photosynthesis, providing the world with oxygen and serving as the foundation of most food webs. The primary groups within the plant kingdom include algae, bryophytes, pteridophytes, gymnosperms, and angiosperms.
Historical Classification Systems in Botany
Initially, the classification of plants was based on superficial morphological traits such as habit, colour, and leaf shape. However, with advances in science, especially genetics and molecular biology, more accurate phylogenetic classification systems have emerged, considering evolutionary relationships.
Classification within the Plant Kingdom
Major Divisions of the Plant Kingdom
Here is a conceptual overview of the classification:
We can further explore each category:
Algae
General Characteristics
Algae are chlorophyll-bearing, simple, thalloid, autotrophic organisms that are predominantly aquatic. They vary in form and size, ranging from unicellular to massive multi-cellular structures.
Reproduction Methods
Algae reproduce through vegetative, asexual, and sexual methods. Vegetative reproduction occurs via fragmentation, while asexual reproduction happens through various spores, and sexual reproduction may exhibit isogamy, anisogamy, or oogamy.
Ecological and Economic Importance
Algae play a significant role in carbon dioxide fixation and oxygen production through photosynthesis. They also form the basis of aquatic food webs and have numerous commercial uses, such as providing hydrocolloids and serving as food supplements.
Bryophytes
Characteristics of Bryophytes
Bryophytes, including mosses and liverworts, are non-vascular plants residing in moist, shaded environments. They are known as amphibians of the plant kingdom due to their need for water for sexual reproduction.
Liverworts vs Mosses
Liverworts feature a thalloid body closely attached to substrates, whereas mosses have leafy, upright structures with spirally arranged leaves.
Role in Ecology and Economy
Bryophytes help in plant succession and soil formation. Moss species like Sphagnum are valuable in horticulture and fuel.
Pteridophytes
Key Features of Pteridophytes
Pteridophytes possess vascular tissues and include ferns and horsetails. Their body is differentiated into roots, stems, and leaves.
Reproduction in Pteridophytes
Reproduction involves spores that develop into gametophytes, which produce male and female sex organs. Water is essential for fertilisation, limiting their geographical spread.
Medicinal and Ecological Significance
Pteridophytes are used for their ornamental value and medicinal properties.
Gymnosperms
Unique Traits of Gymnosperms
Gymnosperms are seed-producing plants where the seeds are "naked," not enclosed in fruits. They include conifers like pines and cycads.
Adaptations to Environment
These plants have needle-like leaves and other adaptations to survive harsh climates. Their roots often form symbiotic associations for nutrient absorption.
Examples and Importance
Notable gymnosperms include Pinus, Cycas, and Ginkgo, which have ecological and economic significance.
Angiosperms
Defining Characteristics
Angiosperms, or flowering plants, have seeds enclosed within fruits. They are the most diverse and widespread group of plants.
Classification of Angiosperms
They are divided into monocotyledons and dicotyledons based on structural differences.
Role in Human Life and Ecosystem
Angiosperms provide essential resources such as food, medicine, and materials.
Advanced Concepts
Modern Approaches in Plant Taxonomy
Numerical Taxonomy
This methodology involves assigning numerical codes to all observable characteristics of plants, providing a comprehensive classification framework.
Cytotaxonomy and Chemotaxonomy
Cytotaxonomy is based on cellular features like chromosome number and structure, while chemotaxonomy utilises the plants' chemical constituents for classification.
Conclusion
Summarising the Plant Kingdom
Understanding the plant kingdom involves studying its various groups, their characteristics, and their roles in the ecosystem. From algae to angiosperms, each group contributes uniquely to our environment, and modern taxonomic methods enhance our comprehension of their diversity and relationships.
Future Perspectives in Plant Classification
As technology progresses, we anticipate even more refined classification systems that will help us understand the complex evolutionary relationships within the plant kingdom, ensuring a richer understanding of botanical biodiversity.
This guide serves as a comprehensive resource for Class 11 Biology students to navigate the intricate yet fascinating world of the plant kingdom.
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