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XI Botany New Chapter-03: PLANT KINGDOM
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Spread the Happiness. Assertion and Reason Statements Feedback: 9008271516XI_Botany_New Chap-03: PLANT KINGDOM
S# Assertion Reason
INTRODUCTION
The Five Kingdom classification categorizes It groups organisms into Monera, Protista, Fungi, Animalia,
1
living things. and Plantae.
Modern plant classification excludes Advancements in scientific understanding of evolutionary
2 previously classified organisms. relationships led to excluding fungi and some
Monera/Protista with cell walls from Plantae.
Cyanobacteria are not classified as algae Revised understanding of evolutionary history, despite their
3 anymore. resemblance to algae, excludes cyanobacteria from Plantae.
Early plant classification systems were Superficial features like color and leaf shape used in these
4 unreliable. systems can be misleading indicators of evolutionary
relationships.
Artificial classification systems Vegetative features influenced by environment don't
5 overemphasized features with limited necessarily reflect true evolutionary relationships between
taxonomic significance. organisms.
Natural classification systems incorporate They consider internal features (anatomy, embryology,
broader evidence to assess relationships. phytochemistry) alongside external characteristics for a more
6
comprehensive understanding of evolutionary affinities.
Phylogenetic classification reflects This approach assumes organisms within a group share a
7
evolutionary history. common ancestor and inherited traits.
Modern classification utilizes diverse data Fossil evidence, numerical taxonomy (computer-analyzed
sources for complex classification issues. observable characteristics), cytotaxonomy (chromosome
8
analysis), and chemotaxonomy (chemical analysis) all aid in
resolving classification challenges.
Numerical taxonomy employs computers to Assigning codes and weights to various features allows in-
analyze a comprehensive set of observable depth analysis of similarities and differences, enabling
9
characteristics. consideration of hundreds of characteristics simultaneously.
Cytotaxonomy and chemotaxonomy provide Chromosome structure and chemical composition can aid in
10 supplemental data for resolving classification differentiating between closely related species with
ambiguities. superficial similarities.
Plant classification revisions reflect evolving The exclusion of certain organisms from the plant kingdom
11 scientific knowledge. exemplifies our improved understanding of biological
relationships.
Natural classification systems aim to represent Underlying features like anatomy, embryology, and
12 natural affinities between organisms. phytochemistry, reflecting shared evolutionary history, are
considered rather than superficial similarities.
Phylogenetic classification depicts It assumes organisms in a specific group descended from a
13 evolutionary relationships. common ancestor and share a set of inherited
characteristics.
Our understanding of biological classification Previously classified organisms may be reclassified based
14 is not static but ever-evolving. on new scientific discoveries, such as cyanobacteria no
longer being considered algae.
3.1 ALGAE
Algae contain chlorophyll pigments. These pigments enable them to absorb sunlight for
15
photosynthesis, making them autotrophic organisms.
Algae exhibit a wide range of shapes and sizes This morphological diversity allows them to occupy various
16 (single-celled to giant kelps). ecological niches (e.g., water column, surfaces) and exploit
different resources.
Algae reproduce asexually (spores) and This reproductive versatility enables them to adapt to
sexually (gamete fusion). changing environments and maximize reproductive success
17 (rapid asexual reproduction, wider dispersal through spores,
genetic variation through sexual reproduction).
Vegetative reproduction in algae involves A broken piece of algae (thallus) containing genetic material
fragmentation. can regenerate into a whole new organism, facilitating rapid
18
asexual reproduction in favorable conditions.
Asexual reproduction in algae involves spores. Spores are dispersal units that germinate into new algae
19 under suitable conditions, allowing for wider colonization of
habitats.
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, Spread the Happiness. Assertion and Reason Statements Feedback: 9008271516
XI_Botany_New Chap-03: PLANT KINGDOM
S# Assertion Reason
Sexual reproduction in algae involves gamete This process shuffles genetic information, leading to
20
fusion (isogamy, anisogamy, or oogamy). offspring with increased diversity and adaptation potential.
There are three main classes of algae: Classification is based on pigment types (chlorophyll a &
21 Chlorophyceae, Phaeophyceae, and b/c/d) and stored food reserves (starch/laminarin/floridean
Rhodophyceae. starch).
Some algae, like kelp, can form massive plant Kelp have complex internal structures for efficient nutrient
22 bodies. and water transport, supporting their large size and growth.
Oogamy in some algae (e.g., Fucus) involves a This seemingly illogical strategy provides protection for the
23 large, non-motile egg and a smaller, motile larger egg cell during fertilization.
sperm.
Algae play a vital role in aquatic ecosystems. As primary producers, they carry out photosynthesis,
24 releasing oxygen and forming the base of the food chain for
many aquatic animals.
3.1.1 Chlorophyceae
Chlorophyceae appear green. Chlorophyll a & b pigments absorb all wavelengths except
25
green, which is reflected.
Chloroplasts contain chlorophyll. Chlorophyll captures sunlight energy essential for
26
photosynthesis in green algae.
Pyrenoids store starch in Chlorophyceae. These structures function as storage units for excess
27
glucose converted to starch during photosynthesis.
Green algae have a rigid cell wall. The two-layered structure (cellulose & pectose) provides
28
support, protection, and maintains shape.
Fragmentation enables vegetative Breaking into pieces allows for rapid asexual reproduction in
29
reproduction. favorable conditions.
Zoospores with flagella facilitate asexual Flagella enable movement, increasing dispersal for finding
30
reproduction. suitable environments.
Sexual reproduction exhibits variation This variation promotes genetic diversity in offspring,
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(isogamous, anisogamous, oogamous). enhancing adaptation to changing environments.
Chlamydomonas, Volvox, Ulothrix, Spirogyra, This diversity showcases morphological variations
32
Chara are Chlorophyceae examples. (unicellular, colonial, filamentous).
Chloroplasts have various shapes (discoid, Shape variation doesn't affect efficient sunlight capture due
33
plate-like). to optimal chlorophyll distribution.
3.1.2 Phaeophyceae
Phaeophyceae appear brown due to This xanthophyll pigment absorbs blue and green
34
fucoxanthin. wavelengths, reflecting brown light.
Brown algae store laminarin or mannitol. These complex carbohydrates serve as reserve molecules for
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future metabolic needs.
Phaeophyceae have a cell wall with an alginic The cellulose wall provides structural support, while the
36
acid coating. alginic acid coating offers protection.
Brown algae have holdfast, stipe, and frond. These specialized structures perform distinct functions
37
(attachment, support, photosynthesis).
Fragmentation enables vegetative reproduction Breaking into pieces allows for rapid asexual reproduction in
38
in brown algae. favorable conditions.
Phaeophycean zoospores have two unequal This difference in flagella size facilitates steering and
39
flagella. efficient movement for dispersal.
Sexual reproduction in brown algae varies This variation promotes genetic diversity in offspring,
40
(isogamous, anisogamous, oogamous). enhancing adaptation.
Ectocarpus, Dictyota, Laminaria, Sargassum, This showcases the morphological diversity within brown
41
and Fucus are Phaeophyceae examples. algae (filamentous, flat, kelp).
Brown algae possess chlorophyll a & c but Fucoxanthin masks the green color of chlorophyll a & c,
42
appear brown. reflecting brown light.
Brown algae have a central vacuole. The large vacuole stores water and maintains turgor
43 pressure, supporting the plant body's shape and buoyancy.
Brown algae possess chlorophyll a & c for These pigments capture light energy at different
44
photosynthesis. wavelengths, maximizing absorption efficiency.
3.1.3 Rhodophyceae
Red algae are red due to r-phycoerythrin The pigment absorbs blue & yellow light, reflecting red light
45
pigment. (complementary absorption).
Most red algae thrive in warm, marine Warmer water offers optimal temperatures for growth and
46
environments. reproduction.
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