fungi

• Characteristics of fungi

  • Some are single-celled
  • Some have complex multicellular bodies
  • Found in terrestrial and aquatic environments
  • Grow by forming multicellular filaments
  • Hyphae plays a role in how fungi obtain food
• Types of fungi

  • yeast
  • molds
  • mushrooms
• How fungi feed

  • Heterotrophs and mostly saprophytic (sapros is Greek for 'decayed')
  • Can digest very tough compounds such as chitin, cellulose, and lignin
  • Very important in nutrient cycling
  • Some are parasitic (e.g. Candida albicans) or yeast infection
  • Parasitic fungi cause diseases in plants, humans, and animals
  • Grow in temperature 20 – 40 0 C
• Feeding

  1. Extracellular digestion

  2. Release enzymes onto the food

  3. The enzymes break down food into simple soluble

  4. Fungi absorb the nutrients
• Fungi evolution

  • Thought to have evolved from Prostista 600 mya
  • Aquatic with a flagellum
  • 460 mya first fungi colonized land
  • Fungi have cell wall that contain polysaccharide chitin
  • Fungi may be closely related to animals
• Morphology of fungi

  • Form a network of tiny filaments
  • Hyphae form an interwoven mass = mycelium
  • Infiltrate the material on which the fungus feed
  • Increase the surface area of mycelium
  • Efficient absorption of minerals
• Fungi reproduction

  1. Reproduce asexually or sexually

  2. through spores formed on reproductive hyphae

  3. Spores carried long distances by wind and water

  4. Germinate under favourable environmental conditions to form mycelium

  5. Asexual reproduction: spores through sporulation and mitosis

  6. Sexual reproduction: Plasmogamy, Karyogamy, Meiosis
• Ecological roles of fungi

  • Decomposers: break down organic material
  • Recycle nutrients from rotting wood, animal corpses, and waste of living organisms
  • Parasitic fungi absorb nutrients from cells of a living host
  • Form a symbiotic relationship with plant roots
  • Allowing plants to absorb water and minerals
  • Some fungi contributes to human diet
• Implications of fungi for humans

  • Used as food (e.g., edible mushrooms)
  • Used in agriculture, forestry and in manufacturing of bread and antibiotics
  • Used to ripen blue cheeses
  • Used to produce beer and bread
  • Cause food spoilage (black bread mold Rhizopus sp.)
  • Cause allergies, infections e.g., ringworm and athlete's foot
  • Crop pests such as wheat rust
  • Some are highly poisonous and hallucinogenic (e.g., magic mushrooms)
• Medicinal uses of fungi

  • Ergot is used to reduce high blood pressure and stop maternal bleeding after childbirth
  • Used in the production of antibiotics e.g., penicillin
  • Cyclosporine which is used to suppress immune system after organ transplant
• Economic importance of fungi

  • Medicinal value
  • Antibiotics such as Penicillin
  • Food (Mushroom)
  • Fermentation (Bread, cheese, beer and wine)
• Phylum Deuteromycota (Imperfect fungi)


  • Lack sexual reproduction
  • Reproduce by means of conidiospores
  • Penicillin antibiotics developed from Penicillium species
  • Cyclosporine = imperfect fungi
  • Cause athlete's foot, ringworm, and respiratory tract disease aspergillosis (Aspergillus spp.)
• Phylum Zygomycota


  • Smallest group (900 species)
  • Bread mold = grow surface of bread, fruits, and vegetables
  • Mostly terrestrial
  • Live in soil, animals, and plants
  • Mostly saprophytic
  • Rhizopus life cycle: Plasmogamy, Zygosporangium, Thick wall coating
• Phylum Basidiomycota


  • Diverse group (50 000 species)
  • Mushrooms, puff balls and shelf fungi
  • Filamentous and have hyphae
  • Reproduce sexually
  • Basidium present
  • Club shape spore-bearing organ
  • Produces basidiospores
  • Basidia are attached to fruiting bodies = basidiocarp
• Phylum Ascomycota


  • 90 000 species that are known
  • Found in marine, freshwater, and terrestrial ecosystems
  • Commonly called the sac fungi (askos = bag/sac)
  • Produce ascospores in a sac
  • Few edible mushrooms
  • Brewer's yeast (Saccharomyces cerevisiae) produces alcohol and CO2 in the fermentation process
• Fungi symbiotic relationships

  • Fungi may form a symbiotic relationship with plant roots
  • Fungi colonize the plant root system
  • Spreads its mycelium
  • Improves the delivery of minerals to plants
  • Mycelium network efficient in acquiring nutrients than plants
  • Plants supply fungi with organic nutrients such as carbohydrates
  • Invade plants that grow in nutrient poor soils
• Plants evolved from autotrophic green algae spirogyra around 470 million years ago
• By 425 million years ago some early plants had traits facilitating life on land
• General characteristics of plants

  • Multicellular eukaryotes
  • Photosynthetic autotrophs
  • Waxy cuticle
  • Stomata
  • Chlorophyll
• General characteristics of plants


  • Cell walls: a rigid layers outside plasma membrane
  • Vascular tissues: complex conducting tissue of more than one cell type
  • Protected gametangia: sex organs
  • Alternation of generations: occurs during plant lifecycle
• Alternation of generations

  Multicellular haploid and diploid phase
• Ancestors of plants

  • Multicellular green algae from kingdom Protista
  • Green algae lived in the water near the seashore
  • Sea shore complicated environmental conditions
  • Strong wave action
  • Algae to evolve structures that anchored them to the rocks
  • Sea shore became drier
  • Evolution of early land plants that moved on land
• Advantages of plants moving on land

  • More sunlight
  • More CO2
  • More nutrients
• Disadvantages of plants moving on land

  • Water loss / drying out
  • Reproduction dependent on water
• Early land plants

  • Related to green algae: chloroplast similarity, cellulose arrangement in cell walls, starch as an energy reserve
  • Differ from green algae: morphological adaptations to land life, Exhibit lifecycle with alternation of generations, Parent plant nurtures and protect the growing embryo
• Plant adaptations to life on land

  • Drying out (desiccation): live in moist environments and have a waterproof surface (cuticle)
  • Gaseous exchange: epidermal tissue (stomata and guard cells) to prevent water loss and regulate gas exchange
  • Support: specialised cells/tissues that support the plant e.g. lignin and cellulose
  • Conduction: vascular tissues i.e., xylem and phloem
  • Growth: apical meristem