PROTISTS

Characteristics Most are unicellular Some form colonies (multicellular)

Cells are eukaryotic Draw the following diagram

Reproduce “mainly” by binary fission

Like moist surroundings

The protist kingdom is very diverse and consists of 3 main groups: Plant-like protists Animal-like protists Fungi-like protists

Plant – Like Protists Contain chlorophyll Can photosynthesize Take in CO2 and give off O2 Are also able to engulf solid food

Plant-Like Protists Example: Euglena Has eye spot Has flagellum used to locate nutrients Has flagellum

Plant-Like Protists Example: Algae Red, green and brown algae Contain chlorophyll Red and brown algae are called seaweed Supplies 80% of the world’s oxygen

Algae Reproduction Can reproduce 3 different ways Fragmentation – asexual, the organism simply breaks apart Binary Fission – asexual Conjugation – sexual There are many variations in reproduction, depending upon the organism itself

Algae: How do we use it? Fertilizer In gels Cosmetics Ice cream Paint

Animal-Like Protists a.k.a. Protozoans Unicellular Heterotrophs (rely on other organisms for food) Must move to obtain food Engulfs food or absorbs directly through their cell membranes Reproduce by binary fission

Protozoans are classified according to their type of locomotion Ciliophora – use cilia (tiny hairs) Sarcodina – use pseudopods Mastigophora – use flagella Sporozoa – parasitic, depend on host fluids for movement

Ciliophora a.k.a. Ciliates Live in both fresh and salt water Example: Paramecium Food enters the mouth pore and exits from the anal pore

Sarcodina Example: Amoeba Moves by extending and retracting its pseudopods Cytoplasm has 2 layers: ectoplasm and endoplasm The fluid movement of endoplasm causes the amoeba to constantly change shape

Sarcodina Feeds by phagocytosis Food gets enclosed in food vacuole Pseudopods flow around the food Engulfs Food gets enclosed in food vacuole Water comes in by phagocytosis or by diffusion through the membrane

Mastigophora Ex: Chilomonas Flagella is made of protein microtubules One of the chief sources of food for the amoeba

Sporozoa Example: Plasmodium vivax Malaria parasite Transferred by mosquitoes and humans Can be treated with drugs Multiply asexually in animals by forming spores and can develop into other sporozoa without fertilization

Example: Giardia lamblia a.k.a Beaver fever Causes stomach upset and diarrhea Flagellated sporozoa

Fungi-Like Protists Slime moulds Prefer cool, shady, moist environments Become amoeba-like or grow flagella OR can produce spores Start as unicellular, but eventually combine with others and become multicellular Useful as decomposers

Protists are VERY important Protists provide marine animals with food and supply the oceans and land with oxygen Phytoplankton (autotrophic-do photosynthesis) are at the bottom of the marine food chain Zooplankton (hetertrophic- don’t do photosynthesis) eat phytoplankton. Both are food to filter-feeding whales

Some protists Trichomonas hominis live in humans’ intestines, feeds on undigested materials, harmless Other protists live in termites’ digestive tract and digest the wood they eat. They couldn’t do this without them!