Overview
This lecture introduces protists and fungi, explaining their characteristics, roles in ecosystems, reproduction, impact on humans, and significance in biotechnology.
Protists: Characteristics and Diversity
- Protists are mostly microscopic, unicellular eukaryotes, but some are multicellular.
- As eukaryotes, protists contain a nucleus and membrane-bound organelles.
- Protists can move using flagella, cilia, or pseudopods (as in amoebas).
- Some protists are animal-like (no cell wall), while others resemble plants or fungi (with cell walls).
- Protists are a diverse group that don't fit into the plant, animal, or fungus kingdoms.
Protists: Habitats, Nutrition, and Reproduction
- Protists live in freshwater, saltwater, soil, and sometimes inside animals.
- Protists can be autotrophs (make their own food, often via photosynthesis) or heterotrophs (consume others).
- Examples: Diatoms and euglena are autotrophs; amoebas and paramecia are heterotrophs.
- Protists reproduce asexually (binary fission) or sexually, with some complex life cycles.
Protists: Ecological and Medical Importance
- Photosynthetic protists produce oxygen and are key food chain producers in aquatic habitats.
- Some protists act as decomposers; others form symbiotic relationships (e.g., with coral or insects).
- Some protists are pathogens: malaria is caused by a parasitic protist spread by mosquitoes.
- Rare species of amoeba can cause severe human infections; certain protists caused the Irish Potato Famine.
Fungi: Characteristics and Ecology
- Fungi are mostly multicellular eukaryotes with cell walls made of chitin.
- Fungi are heterotrophs, absorbing organic matter, and don't photosynthesize.
- Fungi are found in diverse environments: soil, aquatic, indoors, and on hosts.
Fungi: Reproduction and Human Impact
- Fungi reproduce sexually and asexually, often using spores.
- Fungi can cause human infections (ringworm, yeast infections) and impact crops as parasites.
- Fungi play crucial roles as decomposers and in food production (bread, cheese, mushrooms, yeast).
- Many fungi form symbiotic relationships, such as mycorrhizae with plant roots and lichens with algae.
- Important medicines (like penicillin) are derived from fungi.
Fungi and Protists in Biotechnology and Research
- Phytoplankton (protists) are being studied as biofuel sources.
- Some fungi are biocontrol agents against pests, reducing pesticide use.
- Yeasts are used in biotechnology, for example in recombinant DNA technology.
Key Terms & Definitions
- Protist — a diverse group of mostly unicellular eukaryotic organisms not classified as plants, animals, or fungi.
- Eukaryote — an organism whose cells have a nucleus and membrane-bound organelles.
- Autotroph — an organism that produces its own food, usually through photosynthesis.
- Heterotroph — an organism that obtains food by consuming other organisms.
- Chitin — a tough carbohydrate making up fungal cell walls and insect exoskeletons.
- Symbiosis — a close, long-term interaction between two different species.
Action Items / Next Steps
- Review the video details for recommended further reading and real-life amoeba footage.
- Consider learning more about protist and fungi reproduction or their roles in ecological succession.