Biological Kingdoms and Plant Life Processes
Biological Classification: The Five Kingdoms
Kingdom Monera (Prokaryotes)
Nutrition and Metabolism
- Autotrophic and Heterotrophic (Parasitic, Saprophytic, Symbiotic).
Classification
- Eubacteria (True Bacteria)
- Archaea (Halophiles, Thermoacidophiles, Methanogens)
- Mycoplasma (Bacteria lacking a cell wall)
Kingdom Protoctista (Protists)
Includes Protozoa, Unicellular Algae, and Unicellular Fungi/Slime Molds.
Protozoa Classification
Protozoa may be free-living, symbionts, or parasites. They are classified as:
- Flagellates
- Ciliates
- Sarcodina (Amoeboids)
- Sporozoa
Kingdom Fungi
Fungal Classification
- Zygomycetes
- Ascomycetes
- Basidiomycetes
- Deuteromycetes (Imperfect Fungi)
- Lichens (Symbiotic associations)
Kingdom Plantae (Plants)
Key Characteristics
- Eukaryotic and Multicellular Photoautotrophs.
- Cell walls composed of cellulose.
- Store energy as starch.
- Perform cytokinesis.
- Exhibit a diplohaplontic life cycle.
Plant Classification
Plants are sorted into Non-vascular (Bryophytes) or Vascular (Tracheophytes).
- Vascular Plants can be Seedless or Seed-bearing.
- Seed-bearing Plants include Gymnosperms and Angiosperms.
Kingdom Animalia (Animals)
General Classification Criteria
Animals are sorted based on:
- Number of embryonic layers.
- Type of symmetry.
- Presence or absence of an internal cavity (coelom).
Chordates and Vertebrates
Chordates are divided into Protochordates and Vertebrates.
- Protochordates: Urochordates and Cephalochordates.
- Vertebrates: Fish, Amphibians, Reptiles, Birds, Mammals.
Vertebrate Subgroups
- Fish: Chondrichthyans (cartilaginous) or Osteichthyans (bony).
- Amphibians: Anura (frogs) and Urodela (salamanders).
- Reptiles: Chelonia (turtles), Squamata (lizards, snakes), Crocodilia.
- Mammals: Prototheria (monotremes), Metatheria (marsupials), Eutheria (placentals).
Detailed Plant Biology: Structure and Function
Plant Nutrition and Transport
Plants can be Bryophytes (non-vascular) or Cormophytes (vascular).
The Transport Process
- Absorption of water and minerals by the roots.
- Transport of Crude Sap (water and minerals) via the xylem.
- Gas exchange (photosynthesis and respiration) in the leaves.
- Transport of Elaborated Sap (sugars) via the phloem.
Plant Response (Hormones and Movements)
Plant Hormones (Phytohormones)
The most important plant hormones are:
- Auxins
- Gibberellins
- Cytokinins
Plant Movements
Movements are distinguished as Tropisms and Nasties.
- Tropisms (directional growth responses):
- Phototropism (light)
- Geotropism (gravity)
- Hydrotropism (water)
- Thigmotropism (touch)
- Chemotropism (chemicals)
- Nastia (non-directional responses).
Plant Reproduction
Types of Reproduction
Plants reproduce sexually or asexually.
Asexual Reproduction Mechanisms
Important asexual mechanisms include:
- Rhizomes
- Tubers
- Bulbs
- Stolons
Sexual Reproduction (General)
Gametes are formed within specialized structures called gametangia. Male gametangia are Antheridia, and female gametangia are Archegonia.
Reproduction in Seed Plants (Angiosperms)
The reproductive sequence involves flower formation, pollination, fertilization, embryo formation, seed development, and fruit dispersal.
Flower Components
The flower structure includes:
- Protective whorls: The Calyx and the Corolla.
- Reproductive whorls: The Androecium (male) and the Gynoecium (female).
Pollen Grain Structure
A pollen grain is covered by the outer Exine and the inner Intine. Within the Intine are two nuclei: the Vegetative nucleus and the Generative nucleus. Stamen formation is achieved through meiosis.
Gynoecium and Fertilization
The Gynoecium (pistil) is distinguished by the Ovary, Style, and Stigma.
Seed and Fruit Development
Following fertilization, the embryo forms within the seed.
Parts of the Seed
- Testa (outer coat)
- Tegmen (inner coat)
- Albumen (Endosperm)
- Embryo (containing the Radicle/Root, Plumule, and Cotyledons)
Fruit Dispersal Mechanisms
Fruit dispersal ensures propagation (followed by seed germination):
- Autochory (self-dispersal)
- Hydrochory (water dispersal)
- Anemochory (wind dispersal)
- Zoochory (animal dispersal)