Describe protists characteristics (6)
- 1.5B years
- Eukaryotic (have membrane-bound nucleus)
- Single-celled (few multicellular)
- Reproduce as/sexually
- Live in aquatic/moist habitats
- Includes plankton
What are the two types of protist plankton?
Zooplankton: animal-like heterotrophs
Phytoplankton: photosynthetic autotrophs
What are the 3 protist groups?
- Animal-like
- Plant-like
- Fungi-like
Describe animal-like protists (4)
Phylum: protozoa
Heterotrophs (ingest/absorb organisms and dead matter)
Parasitic
Classified based on locomotion … pseudopods
How does movement by pseudopods work?
Cytoplasmic extension and retraction to engulf food particles via phagocytosis (ingesting of particles)
What are the 3 groups of animal-like protists?
Flagellates
Sporozoans
Ciliates
Describe flagellates
- Move using whip-like flagella
- Some parasitic, living in bloodstream, causing disease in animals
- Ex: amoeba
Describe sporozoans
- Not motile (glide, stick to surfaces), require host for transportation
- All parasitic
- Ex: plasmodium vivax (maleria)
Describe ciliates
- Move by cilia (“synchronized swimming”)
- Ex: paramecium
Describe plant-like protists
- Aquatic habitat
- Autotrophic (photosynthetic)
- Organisms containing chlorophyll
Ex: algae
Describe algae
- 2B years old
- Supply 2/3 of world oxygen
- Primary food producer
- Source of energy for aquatic food webs
- Not a real taxonomic group
Describe fungi-like protists
- Live on dead organic matter, resemble fungi at some point during life cycle
Ex: slime molds, water molds
Describe slime molds
- Live on dead logs, grass, etc
- Most of life spent as an amoeba, feeding on bacteria
- Small cells merge into multinucleated single cell plasmodium due to food shortage
- Plasmodium contains thousands of nuclei, no cell wall (largest single-celled organism)
Describe water molds
- Important decomposers in aquatic environment
- Filamentous (appearing to have threads)
- Grow on surface of dead matter
- Decompose matter, absorb nutrients
- Living in moist areas, water
- Grow as masses of fuzzy white threads on dead material
Describe protist reproduction
Asexual (Binary fission)
Sexual (conjugation, spore formation in multi-stage life cycle)
