Plant Diversity Taxonomy Biological ClassificationA. History of TaxonomyB. Kingdom MoneraC. Kingdom ProtistaD. Kingdom Fungi Plant KingdomA. AlgaeB. BryophytaC. PteridophytaD. Gymnosperms Virus Lichen Mycorrhiza The living world

1. Plant Diversity: A
Comprehensive Guide
Welcome to an exploration of the incredible diversity found in the plant
kingdom. This presentation covers taxonomy, classification systems, and the
major plant groups from algae to angiosperms.
by sandeep swamy

2. Understanding
Taxonomy
1 Definition
Taxonomy is the branch of
biology dealing with
identification, nomenclature,
and classification of organisms.
2 Origin
The term was proposed by A.P.
de Candolle in his book
"Theories elementaire de la
botanique."
3 Components
Includes identification, nomenclature, and classification based on
observable characters.

3. Systematics vs. Taxonomy
Systematics
Derived from Latin "Systema," meaning systematic arrangement.
Introduced by Linnaeus. Includes evolutionary relationships
between organisms.
Taxonomy
Focuses specifically on identification, naming, and classification.
Modern taxonomists use external and internal structures, cell
structure, and ecological information.

4. Types of Taxonomy
Cytotaxonomy
Uses cytological characters like
chromosome number, structure,
and behavior to solve taxonomic
problems.
Chemotaxonomy
Based on chemical constituents
like alkaloids, carotenoids, tannins,
polysaccharides, nucleic acids,
and fatty acids.
Numerical Taxonomy
Uses numbers and codes for characters, processed by computers. Gives
equal importance to all characters.

5. Binomial Nomenclature
1 Founder
Established by Carolus Linnaeus, who proposed scientific names
for many plants and animals.
2 Plant Naming
Initiated in "Species Plantarum" (May 1, 1753). Any plant name
proposed before this date is not accepted.
3 Animal Naming
Began with "Systema Naturae" (10th edition, August 1, 1758).

6. International Code of Botanical
Nomenclature
1
Two-Part Names
Species names consist of generic name and specific epithet (e.g., Solanum tuberosum).
2
Capitalization Rules
First letter of generic name capitalized; specific epithet in lowercase.
3
Formatting
Names should be underlined when handwritten or typed; italicized when printed.
4
Attribution
Scientist's name abbreviated after specific epithet (e.g., Mangifera indica Linn.).

7. Types of Biological Classification
1
2
3
4
Practical
Based on economic importance or
human use (e.g., medicinal plants,
spices).
Artificial
Based on one or few superficial
morphological characters.
Natural
Based on complete morphological
characters, representing natural
similarities.
Phylogenetic
Considers both morphology and
evolutionary relationships.

8. Pioneers of Plant
Classification
Aristotle
(384-322 BC)
Greek philosopher who
first classified plants
into three groups: herbs,
shrubs, and trees.
Theophrastus
(371-287 BC)
"Father of botany" who
classified plants into
herbs, undershrubs,
shrubs, and trees.
Carolus
Linnaeus
(1707-1778)
"Father of modern
taxonomy" who
formalized binomial
nomenclature and two-
kingdom system.

9. Taxonomic Categories
1
Kingdom
Broadest category
2
Division/Phylum
Major lineages
3
Class
Related orders
4
Order
Related families
5
Family
Related genera
6
Genus
Related species
7
Species
Basic unit

10. Taxonomical Aids
Herbarium
Collection of dried, pressed plant
specimens on sheets (11.5 × 16.5 inches),
arranged by classification system.
Botanical Gardens
Living plant collections for reference and
identification, with each plant labeled with
scientific name and family.
Museums
Collections of preserved plant and animal
specimens in containers or as dry
specimens for study and reference.

11. Evolution of
Classification Systems
Two-Kingdom System (Linnaeus, 1758)
Divided organisms into Plantae and Animalia based on cell wall presence.
Five-Kingdom System (Whittaker, 1969)
Expanded to Monera, Protista, Fungi, Plantae, and Animalia based on
cell structure and nutrition.
Three-Domain System (Woese)
Proposed Bacteria, Archaea, and Eukarya, dividing Monera into two
domains.

12. Kingdom Monera: Prokaryotes
1 Cell Structure
Prokaryotic cells with peptidoglycan
cell walls, no membrane-bound
organelles, and 70S ribosomes.
2 Genetic Material
Circular DNA in nucleoid region,
often with additional plasmids.
3 Examples
Eubacteria, Blue-Green Algae
(Cyanobacteria), Mycoplasma,
Archaebacteria, Rickettsia, and
Chlamydia.

13. Bacterial Diversity
Bacteria show remarkable diversity in shape: spherical cocci, rod-shaped bacilli, spiral spirilla, and comma-shaped vibrio. Their
movement is facilitated by flagella with complex basal bodies.

14. Bacterial Cell Structure
Cell Envelope
Three-layered structure with glycocalyx
(capsule/slime), cell wall (peptidoglycan),
and cell membrane.
Gram Staining
Gram-positive bacteria retain purple stain
due to thick peptidoglycan layer. Gram-
negative have thinner walls with
lipopolysaccharide outer layer.
Cytoplasm
Contains nucleoid (DNA), ribosomes,
mesosomes, and storage granules. No
membrane-bound organelles.

15. Bacterial Nutrition and Reproduction
Nutrition Types
Autotrophs (photosynthetic or
chemosynthetic) and heterotrophs
(saprotrophic or parasitic). Most diverse
metabolic capabilities in nature.
Reproduction
Asexual reproduction by binary fission or
endospore formation. Genetic
recombination through transformation,
transduction, or conjugation.

16. Cyanobacteria (Blue-
Green Algae)
Structure
Prokaryotic with cell wall,
thylakoids for photosynthesis,
and gas vacuoles. Can be
unicellular, colonial, or
filamentous.
Nitrogen Fixation
Many can fix atmospheric
nitrogen using specialized
heterocyst cells, improving soil
fertility in paddy fields.
Reproduction
Vegetative by binary fission or fragmentation. Asexual by akinete formation
for protection during unfavorable conditions.

17. Kingdom Protista
1
Characteristics
Unicellular eukaryotes, primarily aquatic. Form a link between
other kingdoms.
2
Examples
Dinoflagellates, diatoms, euglenoids, slime molds, and protozoans.
3
Reproduction
Asexual by binary fission or spore formation. Sexual reproduction
through isogamy, anisogamy, or oogamy.

18. Protist Diversity
Protists show remarkable diversity: bioluminescent dinoflagellates, silica-walled diatoms, mixotrophic euglenoids, and the fascinating
plasmodium stage of slime molds that can spread over several feet.

19. Kingdom Fungi
1 Characteristics
Heterotrophic eukaryotes with chitin cell walls. Body composed of
filaments called hyphae that form mycelium.
2 Nutrition
Absorptive nutrition as saprophytes or parasites. Some form symbiotic
relationships as lichens or mycorrhiza.
3 Reproduction
Vegetative by fragmentation or budding. Asexual by spores. Sexual
through plasmogamy, karyogamy, and meiosis.
4 Classification
Divided into Phycomycetes, Ascomycetes, Basidiomycetes, and
Deuteromycetes based on reproductive structures.

20. Fungal Classes
Phycomycetes
Coenocytic aseptate mycelium. Asexual
reproduction by zoospores or
aplanospores. Sexual by zygospores or
oospores.
Ascomycetes
"Sac fungi" with septate mycelium. Produce
ascospores in sac-like asci. Include yeasts,
Penicillium, and morels.
Basidiomycetes
"Club fungi" with septate mycelium and
dolipore septa. Produce basidiospores on
club-shaped basidia. Include mushrooms
and rusts.

21. Kingdom Plantae: Algae
Chlorophyceae Phaeophyceae Rhodophyceae Other Algae
Algae are primarily aquatic, photosynthetic thalloid plants. They lack true roots, stems, and leaves. Classification is based on pigments,
cell wall composition, and stored food. The three main classes are green algae (Chlorophyceae), brown algae (Phaeophyceae), and red
algae (Rhodophyceae).

22. Algal Diversity
Green Algae
Contain chlorophyll a and b. Store starch.
Cell walls of cellulose and pectose. Found
as unicellular, colonial, or filamentous
forms. Most closely related to land plants.
Brown Algae
Contain fucoxanthin pigment. Store
laminarin and mannitol. Cell walls with
algin. Mostly marine and largest in size.
Show holdfast, stipe, and frond structure.
Red Algae
Contain phycoerythrin. Store floridean
starch. No motile stages. Mostly marine.
Important source of agar and
carrageenin.

23. Bryophytes:
Amphibians of Plant
Kingdom
1 Characteristics
First land plants but dependent
on water for fertilization. Lack
vascular tissue and true roots.
Prefer moist, shady habitats.
2 Life Cycle
Dominant gametophyte
generation. Multicellular
jacketed sex organs.
Sporophyte dependent on
gametophyte.
3 Classes
Divided into liverworts (Hepaticopsida), hornworts (Anthocerotopsida),
and mosses (Bryopsida).

24. Bryophyte Classes
Liverworts
Thalloid or leafy. Rhizoids unicellular.
Sporophyte with foot, seta, and capsule
(except Riccia). Reproduce by
fragmentation or gemmae.
Hornworts
Thalloid with unicellular rhizoids.
Sporophyte with foot and elongated horn-
like capsule. Partially photosynthetic
sporophyte.
Mosses
Leafy gametophyte with multicellular
rhizoids. Sporophyte with foot, seta, and
capsule. Spores germinate to form
protonema.

25. Pteridophytes: Vascular Cryptogams
1
Vascular Tissue
First plants with true xylem and phloem, allowing greater height and terrestrial adaptation.
2
True Roots
Possess true roots, stems, and leaves, though still require water for fertilization.
3
Independent Generations
Sporophyte dominant and independent of gametophyte.
Unique alternation of generations.

26. Pteridophyte Classes
Psilopsida
Most primitive vascular plants.
Body with rhizome, scaly
leaves, and rhizoids. Example:
Psilotum, a living fossil.
Lycopsida
Club mosses with
microphyllous leaves. Produce
strobili at stem tips. Examples:
Lycopodium, Selaginella.
Sphenopsida
Horsetails with jointed stems
and nodes. Scaly leaves in
whorls. Example: Equisetum.
Pteropsida
True ferns with large
megaphyllous leaves. Circinate
vernation in young stage.
Examples: Adiantum, Pteridium.

27. Gymnosperms: Naked
Seed Plants
Characteristics
Seed plants with exposed ovules.
Vascular plants with early
secondary growth. Adapted to
xerophytic conditions.
Reproduction
Heterosporous with endosporic
germination. Male and female
cones. Fertilization by
siphonogamy. No fruit formation.
Classification
Divided into Cycadophyta (lower gymnosperms) and Coniferophyta
(higher gymnosperms).

28. Gymnosperm Diversity
Gymnosperms show remarkable diversity: Cycas (sago palm) with large ovules and motile sperm, Pinus (pine) with needle leaves and
winged seeds, Ginkgo biloba (maidenhair tree) as a living fossil, and Ephedra, a medicinal shrub containing ephedrine used for asthma
treatment.

29. Viruses, Viroids, and
Prions
1 Viruses
Submicroscopic obligate intracellular parasites with either DNA or
RNA. Inert outside host cells. First crystallized by Stanley (TMV).
2 Viroids
Discovered by T.O. Diener in 1971. Contain only low molecular
weight RNA without protein coat. Cause plant diseases like potato
spindle tuber.
3 Prions
Smallest proteinaceous infectious agents. Abnormally folded
proteins causing diseases like mad cow disease and Creutzfeldt-
Jakob disease.

30. Lichens and Mycorrhiza: Symbiotic
Relationships
Lichens
Symbiotic association between algae (phycobiont) and fungi
(mycobiont). Classified as crustose, foliose, or fruticose.
Important as pollution indicators and sources of dyes and
medicines.
Mycorrhiza
Symbiotic association between roots and fungi. Ectomycorrhiza
forms external sheath and Hartig net. Endomycorrhiza (VAM)
forms vesicles and arbuscules inside root cells. Enhances
nutrient absorption.