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Kingdom Protista - Chapter 20

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1 Kingdom Protista - Chapter 20
Biology 111

2 Protists Protists are single celled eukaryotes. A few forms are multi-cellular. Heterotrophic or autotrophic Most live in water (aquatic) Protist is any eukaryotic organism that is not a plant, animal or fungus.

3 Classification of Protists
How they obtain nutrition How they move

4 Protists are classified into 3 main groups:
Animal-like Protists - also called protozoa (means "first animal”) Heterotrophs Plant-like Protists - also called algae Autotrophs Fungus-like Protists - decomposers, saprobes heterotrophs

5 Animal-like Protists Four Phyla of Animal-like Protists
Classified by how they move A. Zooflagellates - flagella B. Sarcodines - extensions of cytoplasm (pseudopodia) C. Ciliates - cilia D. Sporozoans - do not move

6 A. Zooflagellates Flagellates have a small number of long flagella, long whiplike hairs that beats to propel the cell. Some nasty parasites are flagellates, including Giardia lamblia, which causes diarrhea and which is found in most of the surface waters of the US. Another is Trypanosoma brucei, which causes sleeping sickness in Africa. Also Trichmonas vaginalis, a sexually transmitted disease.

7 Trichomonas vaginalis: an STI

8 B. Sarcodines Move using pseudopodia ( "false feet" ), which are like extensions of the cytoplasm - ameboid movement Ingests food by surrounding and engulfing food (endocytosis), creating a food vacuole Reproduces by binary fission (mitosis) Contractile vacuole - removes excess water Can cause amebic dysentery in humans - diarrhea and stomach upset from drinking contaminated water

9 Amoebas in Action

10 Mimivirus: infects a species of amoeba and is the largest known virus ever discovered. Mimivirus enters amoeba cells by phagocytosis

11 C. Ciliates Cilia are small hairs surrounding the protist’s body. The cilia beat in a synchronized pattern to cause movement. Paramecium is a typical ciliate. It has a gullet to swallow food, and a contractile vacuole to get rid of excess water. Genetics: the DNA used for sexual reproduction is stored in the small micronucleus. A copy of this information is used to run the cell: the copy is kept in the much larger macronucleus.

12 D. Sporozoans Sporozoans are animal-like protists that have part of their life cycle inside the cells of their hosts. Known as the “PARASITIC PROTISTS” Malaria: Parasite – Plasmodium falciparum (protist) Vector – Female Anopheles Mosquito Vector: an organism that carries parasite, and can transfer the parasite to another organism.

13 Malaria: microbes inside me..
According to the WHO, million cases of malaria occur each year million deaths/year (MUCH MORE than AIDS) Symptoms include fever, headache, vomiting and other flu-like symptoms The protist lives inside the bloodstream eventually clogging capillaries and destroying blood cells, which will lead to death if not treated

14 Vector / Protist? Page 503 of text~ SHOW CLIP ON DESKTOP!!

15 Plant-like Protists: Algae
The plant-like protists are called algae. Most are single-celled, but a few form large multicellular seaweed. The plant-like protists have chloroplasts. Some, like Euglena, also have flagella for movement. Some, such as the diatoms, have calcium carbonate (chalk) or silica shells.

16 Kelp forests White cliffs of Dover are white from plant-like protist shells

17 White Cliffs of Dover The most popular Second World War song written by Vera Lynn. It was written before America had joined World War II, to uplift the spirits of the Allies at a time when Nazi Germany had conquered much of Europe's area and was bombing Britain. The song was written at a time when British and German aircraft had been fighting over the cliffs of Dover in the Battle of Britain: the song's lyrics looked toward a time when the war would be over and peace would rule over the iconic White Cliffs of Dover, Britain’s border with the European mainland. -Wikipedia

18 Multicellular Algae The multicellular algae are commonly called seaweed. They can be classified into red, brown, and green algae. All have plastids, but the pigments in the plastids vary, giving the different colors. Some, like kelp, are very large and contain several different types of cells and tissues to do specialized work. These include leaves for photosynthesis, gas-filled bladders for buoyancy, the root-like holdfast, and tubes to transport nutrients throughout the body. Algae contain the polysaccharide “agar”, which is tasteless and is used to thicken foods such as soft ice cream, and used in petri dishes as food for microbes.

19 Algae Blooms Algae blooms are the sudden growth of a large population of single celled algae. They occur near the coastlines, with the algae feeding on fertilizer runoff and sewage. Algae blooms deplete the oxygen in the water, killing fish and other organisms. Some of the algae also secrete toxins (ex: red tide) causing diseases like paralytic shellfish poisoning.

20 Green Algae The green algae are the ancestors of plants. The term “plant” implies living on the land or derived from plants living on the land. Green algae and plants have very similar chloroplasts. Multicellular green algae ex: Volvox (colonial)

21 Fungus-like Protists: water & slime molds
Like fungi, they are heterotrophs: they get food and energy from other organisms (live or dead).

22 More Fungus-like Protists
The water molds include some of the worst plant diseases. Phytophthora infestans causes rot in plants. In the 1840’s, Phytophthora caused the potato blight in Ireland. The Irish were poor and overcrowded, and lived mostly on potatoes. The blight caused crop failures in several years, resulting in the deaths of of the population. Many Irish came to the US/Canada at that time.

23 Examples of slime molds

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