Kingdom Protista
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Presentation Transcript
Kingdom Protista • All members of this Kingdom, are unicellular or very simple multicellular organisms. • Members of this kingdom have been around for about 1.5 billion years.
Categories of Kingdom Protista • There are two major categories; the protozoa (animal-like) and the protophyta (plant-like)
General Characteristics of the Protozoa • 1. One -celled • 2. Eukaryotic • 3. Shape determined by the cell membrane or a thicker, elastic membrane called the pellicle. • 4. Reproduce asexually and sexually. • 5. Aquatic
General Characteristics of the Protozoa continued • 6. Heterotrophic • 7. Many are motile-use cilia, flagella or pseudopodia. • 8. Important role in food chain and in the decay process. • 9. Dormant protozoa are called cysts. • 10. Two famous protozoa are the paramecium and the amoeba.
General Characteristics of the Protophyta • 1. One -celled, filaments and colonies. • 2. Eukaryotic • 3. Shape determined by cell wall. • 4. Reproduce asexually and sexually. • 5. Aquatic • 6. Phototrophic • 7. Motile by cilia or drift in water.
General Characteristics of the Protophyta continued. • 8. Known for their role in the food chain and for their contribution to the Earth’s oxygen supply. • 9. Dormant cells are called spores. • 10. Two of the most famous protophyta are the Euglena and diatoms.
The Ameba • The common amoeba, Amoeba proteus, belongs to the phylum known as Sarcodina. • It lives in fresh water. • It is an independent cell, with a nucleus and cytoplasm. • It has no permanent organelles.
The Ameba continued • Although the amoeba has a simple structure, it can move, reproduce,capture and ingest food, digest food, egest wastes, respire and respond to stimuli.
The Amoeba-Movement • Movement known as amoeboid movement. • Uses pseudopods, formed by the plasmasol and plasmagel that comprise the cytoplasm of the amoeba.
Foraminiferans • This is another group of sarcodinians. • Abundant in the oceans. • They too move by way of pseudopods. • They are surrounded by shells made up of calcium. • Eventually the remains of the shells may form chalk deposits.
The Paramecium • One of the most complex protozoa. • Unicellular • Prefers stagnant water. • Has a definite shape(unlike the amoeba). • Certain parts of the cytoplasm do certain things.
Cilia • Paramecia move by way of cilia and hence are members of phylum Ciliophora • Note the hair-like cilia on this ciliate.
Formation and Processing of Food Vacuoles • Food is swept by cilia into the cell mouth. • Food passes into the gullet and a food vacuole forms at it’s base. • Enzymes from the cytoplasm enter the vacuole to digest food. • Wastes from the vacuole are expelled through the anal pore.
Locomotion • Ciliates travel along a spiral path, with the cell rotating around it’s long axis. • A sine wave pattern forms.
The Protophyta • There are about eleven thousand species of algal protists. • They are spread over three phyla;Euglenophyta, Chrysophyta, and Pyrrophyta.
Phylum Euglenophyta • Most are unicellular, but a few are colonial. • Animal and plant-like characteristics. • Use photosynthesis to produce paramylum. • In absence of light they are heterotrophic. • Use flagella for locomotion.
Phylum Euglenophyta cont. • A contractile vacuole is present that serves to remove excess water. • The presence of a light sensitive eyespot or stigma, allows the Euglena to locate
Phylum Pyrrophyta - The Dinoflagellates • Unicellular algae. • Photosynthetic and heterotrophic. • Tough outer shell. • All have two flagella. • Reproduction is asexual. • Food stored as oil or starch.
Red Tide • From time to time,there are algal blooms and the so-called red tides form. • Toxins from the dinoflagellates are released. • Fish die from the toxin and paralytic shellfish poisoning(PSP) may occur.
Phylum Sporozoa • Members of this phylum are non-motile protozoa. • An excellent example of a sporozoan is Plasmodium vivax , the causative agent of malaria. • There are two stages involved in the life cycle of Plasmodium vivax ; Asexual(in the human) and Sexual (in the mosquito).
Phylum Sporozoa con’t. • When an infected mosquito bites a human, spores enter the bloodstream and produce gametes in the red blood cells. • When an infected human is bitten by a mosquito, gametes unite in the gut of the mosquito to form a zygote. • In the mosquito, the zygote matures into more spores which are passed on to the next human victim.
Interesting Facts About Malaria • In the days of British colonization of India, soldiers contracted malaria. • The treatment was to give the soldiers quinine mixed with water (tonic water), mixed with gin (to kill the taste). • This gave rise to a popular drink amongst the soldiers known as “Gin and Tonic”.
More Interesting Facts About Malaria • War veterans who caught malaria overseas, have had recurring episodes of this disease. • In fact, this has been observed in patients in nursing homes right here in Kings County.
The Trypanosome • Member of Phylum Mastigophora. • It is a zooflagellate. • Causative agent of African Sleeping Sickness. • Transmitted from infected wild animals by the tsetse fly to humans
Trypanosome continued • Victim develops a fever and becomes weak and anemic. • This is due to the effect of the toxic metabolites produced by this organism.
Trypanosome continued • Finally the parasites invade the fluid surrounding the brain and spinal cord, the person loses consciousness and dies. • Drugs are effective in the early stages of this disease.
