Plant Classification

Plant Classification

• Three Classifications of Reproductive Plants:
  • Bryophyta: Amphibious plants like moss, reproduce with flagellated sperm
  • Gymnosperm: Naked seeds, includes all conifers like pine
  • Angiosperm: Seeds enclosed within an ovary, includes flowering plants

Plant Divisions

• Non-vascular Plants (Bryophytes):

  • Limited by lack of vascular tissue
  • Reproduce with flagellated sperm
  • Rely on diffusion for nutrient transport
  • Thrive in moist environments

• Vascular Plants (Tracheophytes):

  • Possess vascular tissue (tubes) for transporting food, water, and minerals
  • Resistant to drying out
  • Differentiated structures like roots, stems, and leaves

Angiosperm Types

• Monocots:

  • Pedals in multiples of three
  • Long, slender leaves with parallel veins
  • Randomly distributed vascular tissue in stem
  • One cotyledon (seed leaf)

• Dicots:

  • Pedals in multiples of four or five
  • Wide leaves with branching veins
  • Circular arrangement of vascular tissue in stem
  • Two cotyledons.

Plant Tissues

• Three types of plant tissues: roots, stems, leaves
• Conduction Tissue:
  • Xylem: Transports water unidirectionally
  • Phloem: Transports food (sugars)
• Cambium: Produces new xylem and phloem cells

Root Function

• Absorption of nutrients
• Stability and grounding
• Production of compounds (e.g., hormones)

Root Structure

• Primary Root: Originates from the seed
• Secondary Root: Derived from the primary root, smaller in size

Root Types

• Taproot: Found in dicots, long, thick, grows downward
• Fibrous Root: Found in monocots, no main root, many thin roots

Root Parts

• Meristems: Actively growing region, high mitotic activity
• Root Cap: Protects the meristems during growth
• Epidermis: Outer layer, contains root hairs for nutrient absorption

Stem Function

• Defense system
• Storage of water and carbohydrates
• Nutrient transport
• Stabilization and support

Stem Tissues

• Dermal Tissue: Outer surface of the stem
• Ground Tissue: Parenchyma cells surrounding vascular tissue
• Vascular Tissue: Transportation and structural support

Stem Types

• Herbaceous: Soft, green stem, little to no wood
• Woody: Increased diameter each year, found in perennial plants
• Perennial: Lasts many years
• Annual: Lasts one season

Leaf Function

• Photosynthesis
• Gas exchange (oxygen and carbon dioxide)

Leaf Parts

• Blade: Flattened section, positioned along nodes
• Petiole: Stalk connecting the blade to the stem
• Epidermis: Covered by a cuticle to prevent water loss

Stomata

• Location: Located on the underside of leaves, in pairs
• Function: Regulates gas exchange, protects the plant
• Guard Cells: Contain chloroplasts, regulate stomata opening and closing

Stomata Function

• Open: Gas exchange through diffusion (CO2 in, O2 out)
• Closed: Preserves water, often at night

Water Movement in Plants

• Three methods:
  • Root Pressure: Hydrogen bonds draw water upwards
  • Capillary Action: Adhesion, cohesion, and surface tension allow water to move up the cellulose walls
  • Transpiration: Evaporation of water from leaves pulls water upwards in an unbroken chain

Succession

• Gradual change in species composition over time
• Primary Succession: Begins in an area with no soil or living organisms
• Secondary Succession: Occurs in areas disturbed by disasters or human activities (e.g., forest fires, clear cutting)

Explore the fascinating world of plant classifications, including Bryophyta, Gymnosperms, and Angiosperms. This quiz will help you understand the differences between non-vascular and vascular plants, as well as the characteristics that define monocots and dicots.