• Algae

  • Simple autotrophs (photosynthesizers)

  • Photosynthetic organisms essential in the food chain

  • Produce toxins causing harm to humans

  • Red tides caused by algal blooms due to warmer weather and nutrient abundance

• Protozoa

  • Microscopic heterotrophs, not fungi, usually single-celled and motile

  • Eat bacteria and algae, important in sewage control

  • Can parasitize and kill a wide variety of animal hosts

  • Cause diseases like malaria, African sleeping sickness, and Chagas' disease

Algae

• Photosynthetic organisms converting CO2 and H2O to carbohydrates and oxygen

• Essential in the food chain as carbohydrate and oxygen producers

• Toxins from algae can cause symptoms in humans when consumed indirectly through fish or shellfish

• Red tides are algal blooms caused by warmer weather and nutrient abundance

Protozoa

• Microscopic, unicellular, heterotrophic, usually motile organisms

• Some protozoa can live within a host and cause significant problems

• Protozoa can parasitize and kill various animal hosts, leading to diseases like malaria and Chagas' disease

• Protozoa can make regions uninhabitable for centuries

Fungi

• Yeasts are single-celled fungi, while molds are filamentous fungi

• Fungi have chitin in their cell walls and produce spores

• Fungi are aerobic or facultatively anaerobic and decompose carbon compounds

• Fungi can form symbiotic relationships and act as parasites to living tissue

Fungi Disease in Humans

• Fungi can cause infections like yeast infections and allergic reactions

• Fungal diseases can manifest as surface infections or invade tissue

• Some fungi produce toxins causing hallucinogenic effects or infections when inhaled

• Fungi can also cause food spoilage and deterioration of various materials

Other Important Fungi Facts

• Yeast provides bread, beer, and wine

• Some fungi are used in cheese-making and antimicrobial production

• Fungi are used in laboratory research and can be genetically engineered for mass production of molecules like insulin and vaccines

Multicellular Parasites

Helminths

• Types: Nematodes (roundworm), cestodes (tapeworms), and trematodes (flukes)

• Behavior: Invade host tissue, steal nutrients, and cause damage

• Entry into Humans: Burrow through skin (hookworms), ingestion

• Impact: Still a problem affecting millions worldwide

• Life Cycles: Involve more than one host

Nematode Diseases

• Examples: Elephantitis, River blindness, Trichinosis

Tapeworms

• Behavior: Attach to host's intestines, absorb nutrients

Lifecycle of Ascaris

• Ascaris: Largest roundworm infecting the human intestine

Arthropods

Insects and Arachnids

• Role: Serve as vectors of transmission

• Examples: Mosquitos transmitting malaria, yellow fever, dengue fever, West Nile

Fleas

• Characteristics: Small wingless insects, can transmit pathogens

• Historical Impact: Transmit bacteria causing the bubonic plague

Lice

• Types: Body lice can transmit bacterial diseases like trench fever, epidemic typhus, relapsing fever

• Note: Head lice do not transmit diseases

Ticks

• Behavior: Transmit bacteria causing diseases like Rocky Mountain spotted fever, Lyme disease

• Risk: Tick saliva can cause tick paralysis, especially in children

Mites

• Characteristics: Tiny, fast-moving arachnids

• Impact: Do not transmit diseases but can trigger