Protista is an informal term to refer to the eukaryotes that do not belong in the Animalia, Plantae, or Fungi kingdoms A very diverse group, some have traits similar to those of animals, while some are like plants and others are like fungi. And some are like all three! Most are unicellular but some are multicellular (like some algaes) Lack specialized tissues that would group them within the animal, plant, or fungi kingdoms Example: algae lack the vascular tissues characteristic of the plants Fo
The Protists
Protists are Eukaryotic *and most Eukaryotes are Protists!
Protista is an informal term to refer to the eukaryotes that do not belong in the Animalia, Plantae, or Fungi kingdoms A very diverse group, some have traits similar to those of animals, while some are like plants and others are like fungi. And some are like all three! Most are unicellular but some are multicellular (like some algaes) Lack specialized tissues that would group them within the animal, plant, or fungi kingdoms Example: algae lack the vascular tissues characteristic of the plants Found everywhere there is water
Keep in mind, the large multicellular organisms that we know best (plants, animals, and fungi) are the tips of just a few branches on the great tree of life
Barton, et al., Evolution, Cold Spring Harbor Laboratory Press, 2007
Eukaryotes are divided into 5 supergroups
Campbell, et al., Biology, Pearson, 2008
Supergroup Excavata
Some have an ‘excavated’ groove on one side of the cell body Excavates include protists with modified mitochondria and others with unique flagella Three main groups: Diplomonads Parabasalids Euglenozoans
Supergroup Excavata Diplomonads
Lack plastids (organelle that makes chemical compounds) Have mitosomes (reduced mitochondria) Have two nuclei and multiple flagella Most found in anaerobic environments Many are parasites Giardia intestinalis Campbell, et al., Biology, Pearson, 2008
Giardia intestinalis can infect people when they drink water contaminated with feces. Causes severe diarrhea, boiling water kills the parasite. ‹#›
Also have reduced mitochondria called hydrogenosomes (hydrogen gas as a byproduct) Also lack plastids Most found in anaerobic environments Trichonmonas vaginalis
Supergroup Excavata Parabasalids
Very diverse group that includes heterotrpohs, photosynthetic autotrophs, and parasites All have a spiral or crystalline rod inside the flagella (unknown function)
Supergroup Excavata Euglenozoans Campbell, et al., Biology, Pearson, 2008
Kinetoplastids Single large mitochondrion containing an organized mass of DNA called a kinetoplast Trypanosoma sp.
Supergroup Excavata Euglenozoans The Parasite Museum, www.parasitemuseum.com, 2011
Trypanosoma sp. Cause spleeping sickness in humans, which is fatal if not treated. Transmitted by a carrier organism, the African tsetse fly. They are able to evade the host immune system with a ‘bait & switch’ defense. The surface of the parasite is coated with proteins that the host’s immune system uses to eventually recognize and mount an attack. However, after the immune system recognizes the protein and before it can launch an attack the parasite, the new generations have a different surface protein the host’s immune system doesn’t recognize. ‹#›
Brain-Eating Amoebas!!! Not really an Amoeba, it’s an Amoeba-flagellate Naegleria fowleri Lives in warm freshwaters but has also been found in soil and low-chlorinated pools Invades the central nervous system via the nose where it does extensive damage It then travels up nerve fibers into the brain where it begins to eat the brain piece by piece Survival is less than 1% 1937-2007: 121 deaths in U.S 2007: 12 year-old boy and 22 year-old man die at Lake LBJ 2010: 7 year-old boy dies near Glen Rose (10th case in Texas since 2000)
Supergroup Excavata Euglenozoans http://animal.discovery.com/videos/monsters-inside-me-the-brain-eating-amoeba.html http://www.dpd.cdc.gov, 2011
Euglena sp. Are commonly found in pond water ‹#›
Euglenids Have a pocket at one end of the cell from which two flagella emerge Many are ‘mixotrophs’ in that they can swith from autotrophic to heterotrophic to adapt to changes in their environment Euglena sp.
Supergroup Excavata Euglenozoans www.noaa.gov, 2011
Euglena sp. Are commonly found in pond water ‹#›
Large, extremely diverse group of protists Includes some of the most important photosynthetic organisms on Earth as well as some very well known pathogens Two main groups: Alveolates Stramenopiles
Supergroup Chromalveolates
‹#›
Alveolates Have membrane-bounded sacs (alveoli) just under the plasma membrane (unknown function) Includes three subgroups: Dinoflagellates Apicomplexans Ciliates
Dinoflagellates Cells reinforced by cellulose plates Two flagella located in perpendicular grooves Greek dinos= whirling Abundant components of both marine and freshwater plankton
Supergroup Chromalveolates Alveolates Dave Hill, www.botany.unimelb.edu.au, 2011
‹#›
Dinoflagellates Red tide: dinoflagellate bloom caused by high nutrients Toxins produced by some have caused massive kills of invertebrates and fishes
Supergroup Chromalveolates Alveolates www.oddee.com, 2011
Bloom= episode of rapid population growth Red because of the color of most dinoflagellates High nutrients from things like runoff from a storm (fertilizers, etc.) Humans who eat molluscs have also been affected, accumulating until sometimes fatal ‹#›
Dinoflagellates Zooxanthellae Live in a symbiotic relationship with organisms like coral Photosynthetic autotrophs that provide the host with sugars
Supergroup Chromalveolates Alveolates Scott R. Santos, Auburn University
‹#›
Dinoflagellates Zooxanthellae
Supergroup Chromalveolates Alveolates Eric Yao, 2011
‹#›
Apicomplexans Nearly all are parasites Most have intricate life cycles requiring two or more host species Plasmodium sp. (malaria)
Supergroup Chromalveolates Alveolates The American Society for Clinical Investigation, 2011
‹#›
Ciliates Large, varied group Use cilia to move and feed Have two types of nuclei: tiny micronuclei and large macronuclei Usually reproduce asexually by binary fission Very common in freshwater, some in saltwater Paramecium sp.
Supergroup Chromalveolates Alveolates Power And Syred / Science Photo Library, 2011
‹#›
Comments