Understanding Forest Ecosystems: Flora, Soil, and Life Cycles

Forest Ecosystems: A Comprehensive Look

Forest: A natural ground dominated by trees. Vegetation: Various species of plants with 3 strata: arboreal, shrubby, and herbaceous. Conditions: Light, heat. Virosta: Composition of residue that accumulates sun.

Plant Types

• Bryophytes (moss, liverwort)
• Pteridophytes (fern, horsetail)
• Spermatophytes (seed plants)

Gymnosperms (not enclosed seeds). Angiosperms (enclosed seeds). Vegetation Zones: Forest (arboreal), thicket (tall shrub), springs (low shrub), meadow (herbaceous).

Revolt: Perennial, deciduous. Mineral salts (active absorption via PX transport - against gradient, sometimes with gradient). Concentration: Hypotonic (-), isotonic (=), hypertonic (+).

Osmosis and Photosynthesis

Osmosis: Process of water absorption by cells from roots due to concentration differences. Water moves from low concentration to high intracellular concentration. Photosynthesis: CO2 + H2O + light → sugars (CH2O) + O2 + H2O. Two phases: light-dependent and light-independent. Light energy is converted to chemical energy, then used to fix CO2 into organic molecules.

Parenchyma: Chlorophyll-containing tissues (transfer energy).

Species Adaptations

• Hygrophytes (require high moisture)
• Heliophytes (require high light)

Plant Cell: Cell wall, cytoplasm, nucleus, cell membrane, vacuole, chloroplast. No centrioles, flagellum, or capacity for movement.

Sunny: South-facing movement. Plant Climbing Adaptations: Caulogenic: ivy (aerial roots), spines: blackberry, rose (rigid and sharp), tendrils: bindweed (fixed), twining: winding around others.

Plant Responses

Auxin: Tropism: response to stimuli. Phototropism: curvature due to light detection. Thigmotropism: coiling upon contact.

Ecological Matrix

Riera: Ecological matrix: environmental variables.

Plant Divisions

Bryophytes: Simple structure, moist environment (moss and liverwort), dependent on water for nutrition and reproduction. Pteridophytes: Dependent on water, simple vascular system for nutrient and water transport, reproduces via spores, simple stem, large leaves (fronds) (fern, horsetail).

Soil Organisms

Organisms of the Soil: Virosta, Detritivores: Feed on dead organic matter (earthworms). Coprophagy: Feed on excrement (flies, larvae). Saprophytes: Decomposers, transfer organic matter to inorganic forms.

Fungi

Fungi: Separate kingdom, eukaryotic, multicellular or unicellular. Multicellular body: mycelium (produces spores), hyphae (filaments forming mycelium). Mushroom: spore-bearing structure.

Aquatic Ecosystems

Aquatic Ecosystems: Pool: Producers are plants and algae. Macrophytes: Aquatic plants. Hygrophytes: Adapted to waterlogged, moist soil, shelter for many aquatic vertebrates (margins). Hydrophytes: Rooted to the bottom, leaves floating on the water.

Algae and Cyanobacteria

Algae: Protoctists, eukaryotic, photosynthetic, aquatic, various colors, uni/multicellular, reproduce sexually/asexually. Groups: Chlorophytes, Cryptophytes, Chrysophytes, Euglenophytes, Dinoflagellates. Cyanobacteria: (Prokaryotes) Enriched atmosphere with oxygen millions of years ago = marine and inland waters.

Decomposition

Decomposing Organisms: Bacteria and fungi living on remains of other organisms (leaves) and small organisms (protozoa, crustaceans), facilitating decomposition.

Plant Life Cycle

Cycle Vital Plants: Species: Hum: Gametes (eggs and sperm) with 2n, n chromosomes (diploid, haploid). Meiosis: Cell division producing reproductive cells (reduction of chromosomes). Plants: Alternation of generations, meiosis forms spores, which develop into gametophytes = produce gametes, sporophytes (diploid) and haploid gametes produce another. Diplohaplont: Alternation of generations between sporophyte and gametophyte.