Parasitic Fungi

• Definition of Parasite:
  • A parasite is an organism that consumes nutrients from living cells or tissues.
  • They typically do not kill their hosts as they rely on them for nourishment (e.g., fleas, mosquitoes).
• Fungal Parasites:
  • Approximately 30% of known fungal species are parasitic, with the percentage varying by location.
  • Examples of parasitic fungi in humans include:
  • Athlete's Foot: a common fungal infection of the skin.
  • Vaginal Yeast Infections: caused by Candida species.
  • Lung Infections: more common in immunocompromised individuals.
  • Ringworm: actually a fungus, despite the name suggesting it is a worm.

Commercial Importance of Fungi

• Applications in Food:
  • Fungus is commercially important for producing products like bread, beer, wine, and cheese.
  • Yeast is used in bread making (causes dough to rise) and in fermentation for alcoholic beverages.
• Example of Fungi in Cuisine:
  • Inoculating corn with specific fungi for consumption (e.g., wheat la coche in Mexico).
  • Fungal products include blue cheese, which is characterized by its blue-green mold (specific types of fungus).

Fungi and Antibiotics

• Some fungi are utilized to produce antibiotics (e.g., Penicillin) that inhibit bacterial growth.
• The process involves isolating the substance produced by the fungus that can prevent bacterial growth.

Symbiotic Relationships Involving Fungi

• Mycorrhizae:
  • A symbiotic association between fungi and plant roots.
  • Fungi increase the surface area for absorption of water and minerals from the soil.
  • In return, fungi absorb carbohydrates produced by the plants.
• Lichens:
  • A symbiotic relationship between fungi and either algae (photosynthetic protists) or cyanobacteria.
  • Lichens can survive in harsh environments and help in soil formation by breaking down rock over time.

Overview of Animals

• Defining Characteristics:
  • Animals are multicellular, eukaryotic organisms lacking cell walls.
  • They are heterotrophic, requiring other organisms for nourishment.
  • Definition includes having muscle cells for movement and a nervous system.
  • Most reproduce sexually, although some can reproduce asexually (e.g., regeneration in sea stars).

Development and Life Cycles of Animals

• Stages of Development:
  • Animals go through various developmental stages:
  • Juvenile stages may look similar to adults (e.g., humans).
  • Some exhibit drastic differences (e.g., caterpillars to butterflies).
• Metamorphosis: The change from juvenile to adult can include significant physical transformation.

Cambrian Explosion

• Evolutionary Timeline:
  • The Cambrian Explosion (approximately 525-535 million years ago) marks a rapid diversification of animal forms.
  • Increased atmospheric oxygen levels supported larger body sizes and complex interactions (predator-prey dynamics).

Body Symmetry in Animals

• Types of Symmetry:
  • Animals exhibit radial symmetry (e.g., jellyfish) or bilateral symmetry (e.g., humans).
  • Bilateral symmetry is more advanced, allowing for streamlined movement and organization of body parts.

Phylum Overview

• Sponges (Phylum Porifera):
  • Simple animals without true tissues; they feed by filtering water through their porous bodies.
• Cnidarians (Phylum Cnidaria):
  • Include jellyfish and corals; have stinging cells (cnidocytes) for capturing prey.
  • Exhibit radial symmetry and have a gastrovascular cavity.
• Mollusks (Phylum Mollusca):
  • Characterized by soft bodies, often with shells.
  • Include gastropods (snails, slugs), bivalves (clams, oysters), and cephalopods (squids, octopuses).