Fungi & Plant Kingdom Detailed Study Notes

Kingdom Fungi

  • Ecological Roles

    • Parasitic fungi

    • Invade living tissue.

    • Human examples: tinea (ringworm), fungal nail infections.

    • Also parasitize other animals and plants.

    • Saprophytic (decomposer) fungi

    • Break down dead organic matter; recycle nutrients and “clean up” ecosystems.

  • Representative Morphologies

    • Mushrooms, molds, yeasts.

  • General Life Cycle

    • Fruiting body (mature structure) releases airborne spores (lightweight).

    • Spores germinate → grow filamentous hyphae.

    • Hyphae interweave into a subterranean mycelium.

    • New fruiting body emerges → cycle repeats.

    • Life-cycle alternation of nuclei: haploid nn hyphae, often brief diploid 2n2n nuclei after sexual fusion (species-specific details).

  • Four Major Fungal Phyla

    • Basidiomycota ("club fungi")

    • “Classic” cap-and-stalk mushrooms in forests; spores on basidia.

    • Ascomycota ("sac fungi")

    • Distinct ascus (sac) containing spores.

    • Includes yeasts (e.g., Saccharomyces cerevisiae).

      • Capable of anaerobic fermentation → by-product C<em>2H</em>5OH\text{C}<em>2\text{H}</em>5\text{OH} (ethanol).

      • Ethanol eventually reaches toxic levels and kills the yeast.

    • Penicillium genus

      • Source of first antibiotic penicillin (major historical impact; alternate-history anecdote from TV show “Sliders”).

    • Zygomycota ("zygote fungi")

    • Sexual spores form thick-walled zygospores.

    • Common example: bread mold Rhizopus.

    • Chytridiomycota ("chytrids")

    • Only fungal group with flagellated spores → strictly or primarily aquatic.

    • Often presented as the most ancestral branch; loss of flagella precedes other lineages.

Lichens (Fungus + Photosynthetic Partner)

  • Symbiosis traditionally taught as one fungus + one green alga (or cyanobacterium).

  • National Geographic update: molecular studies reveal a third partner—a second, distantly related fungus forming an outer layer.

  • Diversity & ubiquity

    • Occupy ≈7%\approx 7\% of Earth’s surface.

    • Morphotypes: crustose, foliose, fruticose (hair/pendant).

    • Growth rates vary →\to some expand ≈3 ft yr−1\approx 3\,\text{ft yr}^{-1}; others live ≈10,000 yr\approx 10{,}000\,\text{yr}.

  • Real-world uses & observations

    • Field photography; researcher with >16,00016{,}000 lichen specimens.

    • Indigenous peoples distinguished edible vs. toxic species (e.g., presence of vulpinic acid).

Kingdom Plantae Overview

  • Two broad divisions based on vascular tissue presence.

Non-Vascular Plants (Bryophytes)

  • Mosses, liverworts.

  • Lack true leaves, roots, stems; no xylem-phloem network.

  • Small, low-growing; rely on surface water diffusion.

Vascular Plants (Tracheophytes)

  • Possess conductive vascular bundles (“tubes”).

    • Xylem: moves water & inorganic nutrients upward from roots.

    • Phloem: distributes sugars, amino acids, lipids downward from leaves.

  • Sub-groups:

    • Seedless vascular plants (Ferns, horsetails)

    • Reproduce by spores; sori visible on leaflet undersides.

    • Seed plants

    • Gymnosperms (“naked seeds”)

      • Conifers, cycads, ginkgo.

      • No flowers/fruit; seeds exposed on cones or cone-like structures.

      • Dominant life stage: sporophyte (diploid 2n2n)—considered evolutionarily “primitive” yet still highly successful.

      • Examples & notes

      • Conifers: pine, fir (woody cones).

      • Cycads: palm-like; stiff, spiny leaves (can puncture skin!).

      • Ginkgo biloba: “living fossil”; fan-shaped leaves; fleshy seed coat resembles fruit but is actually part of seed.

      • Other living-fossil parallels: coelacanth fish, dawn redwood tree.

    • Angiosperms (“encased seeds”)

      • Produce flowers; seeds enclosed in fruits.

      • Dominant life stage: gametophyte (haploid nn) is highly reduced, viewed as more “advanced”.

      • Real-world twist: any structure containing seeds ≡ fruit (botanically) → tomatoes, cucumbers, peppers, rice grains, nuts, etc.

Angiosperm Sub-Categories

  • Monocots (Monocotyledonae)

    • One seed leaf (cotyledon).

    • Parallel leaf venation; scattered vascular bundles; floral parts in multiples of 3.

    • Examples: lilies, grasses, palms, orchids.

  • Dicots (Dicotyledonae)

    • Two cotyledons.

    • Net-like venation; vascular bundles arranged in a ring; floral parts in 4s/5s.

    • Includes most broad-leaf trees, shrubs, beans, etc.

Flower Anatomy (testable)

  • Receptacle – base that supports floral organs.

  • Female (Carpel/Pistil)

    • Stigma – sticky pollen-landing surface.

    • Style – stalk connecting stigma to ovary.

    • Ovary – houses one or more ovules (become seeds after fertilization).

  • Male (Stamen)

    • Anther – produces pollen (microspores).

    • Filament – supporting stalk.

  • Perianth

    • Petals – colorful, attract pollinators.

    • Sepals – green, leaf-like outer whorl protecting bud.

(Expect diagram labelling on the next exam. Canvas + Safari image bug → use Chrome/Firefox/Edge.)

Connections, Implications & Real-World Context

  • Medical: antibiotics (penicillin), antifungal treatments, ethanol production for beverages & biofuels.

  • Ecology: fungi drive decomposition cycles; lichens pioneer species on rocks → soil formation; vascular plants underpin terrestrial food webs.

  • Evolutionary insight: flagellated chytrid spores hint at aquatic ancestry; alternations in dominant life phases (haploid vs. diploid) chart plant evolution.

  • Ethical/Philosophical: discoveries like third lichen partner remind us to “keep an open mind” and illustrate the collaborative nature of science; alternate-history thought experiments (no penicillin) highlight fragile human progress.

Numbers, Data & Formulas to Remember

  • Lichens cover ≈7%\approx 7\% of Earth’s land surface.

  • Some lichens grow ≈3 ft\approx 3\,\text{ft} per year; others live ≈10,000 yr\approx 10{,}000\,\text{yr}.

  • Researcher’s personal collection: >16{,}000 lichen specimens.

  • Ethanol chemical formula: C<em>2H</em>5OH\text{C}<em>2\text{H}</em>5\text{OH}.

  • Haploid vs. diploid notation: nn vs. 2n2n.

Study / Exam Tips

  • Be able to sketch or label the fungal life cycle & flower anatomy.

  • Distinguish all four fungal phyla and provide at least one example each.

  • Know vascular tissue functions: “xy-UP” (xylem up) vs. “phlo-DOWN” (phloem down).

  • Memorize monocot vs. dicot diagnostic traits.

  • Review definitions: saprophytic, parasitic, mycelium, living fossil, fruit (botanical vs. culinary).

  • Practice matching plant groups with their dominant life phase (sporophyte 2n2n vs. gametophyte nn) and reproductive strategy (spores vs. seeds).