Plant Kingdom: Classification and Overview

Introduction to Plant Kingdom

• Acknowledges the stress students face due to backlogs.
• Recommends focusing on one-shot lectures and teacher's content to catch up.
• Covers the Plant Kingdom, detailing various plant groups within it.

Overview of Plant Groups

• Discusses five main plant groups: Algae (Thallophyta), Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms.
• Bryophytes are simple plants lacking proper vascular tissues, such as xylem and phloem.
• Algae's placement in the Plant Kingdom is justified by characteristics shared with other plant members, like photosynthetic ability, cell walls, and eukaryotic cells.
• Pteridophytes possess leaves, stems, roots, and vascular tissues but lack seeds.
• Gymnosperms are large plants with stems, roots, leaves, and seeds but no flowers or fruits.
• Angiosperms, or flowering plants, are characterized by the presence of flowers and fruits.

Plant Classification Systems

• Artificial System:
  • An early attempt using vegetative characters like leaf shape, given by Carolus Linnaeus.
  • Limitation is that vegetative characters are easily influenced by environmental changes.
• Natural System:
  • Developed by George Bentham and Joseph Dalton Hooker.
  • Considers both external (morphological) and internal (anatomical) features, including cell structure and embryology.
  • Limitation: Fails to describe evolutionary relationships between plant families.
• Phylogenetic System:
  • Proposed by Engler and Prantl and focuses on evolutionary relationships for classification.
  • Classification assumes plants in the same group share evolutionary ties.

Modern Taxonomy Methods

• Chemotaxonomy: Classifies plants based on their chemical constituents.
• Cytotaxonomy: Uses cytological information, including cell structure and chromosome characteristics.
• Numerical Taxonomy: Employs computer software to analyze plant characteristics, assigning equal importance to each. This provides relationship and better classification.

Thallophyta (Algae)

• Algae encompass various types, excluding blue-green algae (Cyanobacteria), which belong to Kingdom Monera.
• Algae Habitats: Mostly aquatic but also found in soil, on stones, and in association with other organisms.
• Algae is placed in the plant kingdom due to photosynthetic ability, cell walls, and eukaryotic nature.
• Chlorophyll presence allows photosynthesis, giving many algae a green color.

Algae: Forms and Structure

• Forms vary: unicellular (Chlamydomonas), colonial (Volvox), filamentous (Spirogyra, Ulothrix).
• Thalloid Body: A network of filaments creates an undifferentiated structure without a proper shape.
• Kelps are brown algae with thalloid bodies that can grow up to 100 meters.

Algae Reproduction

• Vegetative Reproduction: Utilizes fragmentation, where each fragment develops into a new alga.
• Asexual Reproduction: Relies on zoospores, flagellated spores that develop into new algae under favorable conditions.
• Sexual Reproduction (3 types):
  • Isogamy: Gametes are similar in structure and size, e.g., Spirogyra (non-flagellated), Ulothrix (flagellated).
  • Anisogamy: Gametes are dissimilar in structure and size, e.g., Eudorina.
  • Oogamy: A small, motile male gamete fuses with a large, non-motile female gamete, e.g., Volvox and Fucus.

Algae Classification

• Algae is classified into three groups: Chlorophyceae (green algae), Phaeophyceae (brown algae), and Rhodophyceae (red algae).
• Factors for classification: photosynthetic pigments, cell wall composition, and form of food storage.

Chlorophyceae (Green Algae)

• Key features:
  • Major Pigments: Chlorophyll a and b.
  • Food Storage: Starch.
  • Cell Wall: Composed of cellulose (inner) and pectine (outer).
  • Flagella: Two to eight equal-sized flagella apically positioned.
  • Habitat: Fresh, brackish, and marine water.
• Structure:* -Cell Contain: Chloroplast in each cell contain chlorophyll & differ in shapes (discoid, plate-like, reticulate, cup-shaped, spiral, or ribbon-shaped)
  • Contain structures called pyrenoids, which are used for the storage of protein and starch.

Chlorophyceae (Green Algae) - Reproduction

• Vegetative reproduction: fragmentation.
• Asexual reproduction: zoospores produced in zoosporangia.
• Sexual reproduction: isogamous, anisogamous, or oogamous.
• Examples: Ulothrix, Volvox, Spirogyra, Chlamydomonas, Chlorella, and Cara.
• Mnemonic tip to remember algae: "Ultra Violet sun rays can cause cancer"

Phaeophyceae (Brown Algae)

• Key features:
  • Pigments: Chlorophyll a, c, fucoxanthin, and xanthophylls.
  • Food Storage: Laminarin, mannitol
  • Cell Wall: Cellulose (inner) and algin (outer). Algin is a gel-like substance.
  • Flagella: Two unequal flagella, laterally attached.
  • Habitat: Brackish and marine water
  • Plant body: differentiated into holdfast, stipe, and frond.
    • Holdfast: Structure for attachment to Substratum.
    • Stipe: Stock-like structure that connects holdfast to frond.
  • Frond: Leaf-like appearance part with photosynthetic pigment.

Phaeophyceae (Brown Algae) - Reproduction

• Vegetative Reproduction: Fragmentation
• Asexual Reproduction: zoospores (pear-shaped, two unequal flagella).
• Sexual Reproduction: isogamous, anisogamous, or oogamous.
  • Fertilization: Occurs in water or inside oogonium.
• Examples: Sargassum, Ectocarpus, Laminaria, Fucus, and Dictyota
  • Acronym: SELF DP

Rhodophyceae (Red Algae)

• Key features:
  • Pigments: Chlorophyll a, d, phycoerythrin.
  • Food Storage: Floridean starch.
  • Cell Wall: Cellulose (inner), pectin, and polysulfate esters (outer).
  • Flagella: Absent
  • Habitat: Mostly marine; are found at the surface and in deeper parts of the ocean.

Rhodophyceae (Red Algae) - Reproduction

• Vegetative Reproduction: Fragmentation.
• Asexual Reproduction: Non-motile spores.
• Sexual Reproduction: oogamous, post-fertilization developments.
• Examples: Polysiphonia, Porphyra, Gelidium, and Gracilaria.

Algae: Economical Values

• Significance:
  • Producers in aquatic food chains.
  • Fix carbon dioxide.
  • Increase dissolved oxygen.
• Edible Algae - 70 Species Reported: (e.q., Laminaria, Porphyra, Sargassum) are consumed as food, especially in Asian countries.
  • Two species (Chlorella and Spirulina) are used by space travelers due to high protein content.
• Hydrocolloids Use: Algin (from brown algae) and carrageenan (from red algae) are hydrocolloids used in making ice cream and jellies.
• Agar: Produced by Gelidium and Gracilaria is used in laboratories for growing microbes.

Bryophytes: Introduction

• Includes liverworts and mosses.
• Known as "amphibians of the plant kingdom" due to dependence on water for completing life cycle.
• Habitat: damp, humid, and shaded locations.
• Characteristics: photosynthetic, lack vascular tissue (xylem and pholem), non-vascular plants and non-seed and non-flowering structure.
• Plant body: not properly differentiated into true Root, Stem, and Leaves
• Rhizoids structure is used for absorbing water mineral in the base and can be unicellular or multicellular.
• Key terms:
  • Gametophyte: Structure that produce gametes (sperm and egg); haploid (n).
  • Sporophyte: Structure that produces spores; diploid (2n).

Bryophytes: Gametophyte Structure

• Main plant body is a gametophyte (haploid).
• Gametes are produced in sex organs:
  • Male sex organ (atheridium): Produces biflagellate antherozoids.
  • Female sex organ (archegonium): Flask-shaped and produces a single egg.
• Dioecious and Monoecious Nature: Some Bryophytes have both structures in the same thalli.

Liverworts vs. Mosses: Key Differences

Bryophytes: Asexual Reproduction

• Fragmentations: Thallus fragments into multiple pieces that form into a new thalli
• Gemae:
  • Gemmae mainly occur in Liverworts where Gemma cups produces Gemmae.
  • Gemmae are green, multicellular, aquatic bodies that detach from parents bodies and germinate to form a new individual.

Bryophytes: Sexual Reproduction

• Aetheridium produces antherozoid while archegonium releases egg. Water provides a platform and the transportation of antherozoid to egg for fertilization :fertilization ---> results in a diploid zygote which develops into----> an embryo----> sporophyte
• Sporophyte consists of:
  • Food: stores nutrition and absorbs water-mineral.
  • Ceta: A long stalk
  • Capsule: meiosis produces spore.

Mosses - Life Cycle (Review):

• Steps: Spores to 1. Protonema to 2. Latterel buds (leaf gametophyte) ---> Male/Female parts
• The lifecycle of mosses:
• Achregonia ----> Fusion creates ----> Zygotes -- Meosis---> Capsules -> Spores to Protonemato -> Latter Bud and Cycle continue.

General notes on Both:

• Sex organs are Archegonia or Anthredian.
• They both need water for transport, but bryrophytes are much simpler and easier for study.

Bryophytes: Economical Values

• Used as food for animals.
• Soil binds help soil binds and prevent soil erosion.
• Used to make successions and create an environment or Eco System for plant life to began by bryophytes and other algaes.
• Peat is another material that contains hydroscopic material use for packages.
• Sphagnum: A genus of moss used as fuel.

Pteridophytes

• Includes horsetails and ferns.
• Characteristics:
  • Location/Environment: Cool and damp place, shaded place, however, few can grow in sandy soil as well.
  • Sporophtic - vascular (xylem and pholem) - NO SEED OR FLOWER.
  • Structure consists of an actual root, stem, and leaves.
• Classification:
  • Four classes : Psilopsida; Lycopsida; Sphenopsida; Pteropsida
  • Leaf types -
  • Macro: Large leaves (example Fern) -Micro: Small leaves (Example Equsetum and Selaginella)

Terms Used In Pteriophtyes/ Fern:

• "Sporophyl" is used to help create or to get Sporangla to give cells, and cells give spores with germination in the right environments.

Ptericophyles structure/ Cycle and details:

• Spore mother cell undergoes (MIOSIS) for spore production then goes through germinate state into Gemophye.
• The Male = Antherozoids MultiFlag,
• Female = Ag cell -Both create ---- Fusion. H20 is very important for life cycle

Gemtofighte- Sex oorgans and importence for each.

• A Male is called 3-Dium, which produce an egg
• A Female parts - archeqoniam helps with multi flag to join Aetherdiodes for further process.

Pteridophytes - Types of Spores:

• Homoporous - creates same spores - Example is most of the Ptero plants
  • Different spore production in each type "Salvinailia and "Selaginalia/ (is Heterosporys ). Example

Brief Note Differentiations - Pterophytes vs Bryophites:

• Ptero body plan is different than Baryo
• Ptero contains actual root, stem, and Leave, whereas Brys don't.
• Xyle/Ploem are absent in Bryo but present In ptero.
• In conclusion, one is dependent, and the other is independent and have more cell division cycles.

Introduction to Gymnosperms

• Gymnosperm refers to "naked seeds."
• The world's largest tree is a Gymnosperm.
• Vascular Plant with Seed. SPORES - has Root stem leaves with no seed cover
• They don't consist of Flowers or Fruit but cones instead help grow.

Differences between Pinus vs Cycads

• Pinus is branchy.
• Cycads is unbranching.
• Pinus Leafs are simple and Cycads has leaves that are pinnepally Compound leaves;
• Pinus Root and Fungai connect which call Microhiza.

Cycads + signbo bacteria

• Are called colloar roots as nitrogen fixing occur.

Adapting Factors for Conifers:

• Leaves lose less water from needles, have a thick Q-Ticle, and depressed stemota in conifer.

Gymnosperm life cycle:

• Spores are created (and Miosos is in effect0, and they are transferred through the air called (pollon transfer).
  • Mega Spores and females parts get pollinated through the air (male part transfer) and both fuse for fertilization.
  • The Egg starts developing inside the plant and all is happening simultaneously for a long duration.
  • The new Spoe plant grows, and cyclal continues.

Agnosperms:

• They are flowering with seed and found everywhere.
• Have a wide range, and sizes are small or high/ large
• There are 2 Types: monocot and Dicot with differences in root and stem and leaves.

Monocol vs dicol:

• Monocol has a fiber root and dicol has a taproot.
• MOnoco has a bad stem and decol has a hard stem
• MOnoco leaf has parallel leaves pattern and Dicol has a network pattern.

Explore the Plant Kingdom, including Algae, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms. Learn about their characteristics, classification, and evolutionary relationships within the plant kingdom. Understand the differences between artificial and natural classification systems.