Protists
Protists belong to the Kingdom Protista, which include mostly unicellular organisms that do not fit into the other kingdoms.
Chararacteristics of Protists
- mostly unicellular, some are multicullular (algae)
- can be heterotrophic or autotrophic
- most live in water (though some live in moist soil or even the human body)
- many have method of movement
- ALL are eukaryotic (have a nucleus)
Protozoa - name means "first-animal"
Protozoa are animal-like protists, that is they move and eat and behave like animals. They are heterotrophic
Algae - plant-like protists, most do not move, they use choroplasts to photosynthesize (autotrophic). Many algae are multicellular.
Examples of Protozoa
Ameba (See Ameba Coloring Sheet)
lives in water
appear like blobs
moves using pseudopodia ( "false feet" ), which are like extensions of the cytoplasm
reproducing by binary fission (mitosis)
contractile vacuole - removes excess water
can cause amebic dysentery in humans - diarrhea and stomach upset from drinking contaminated water
ingests food by surrounding and engulfing food (endocytosis)
Paramecium (See Paramecium Coloring Sheet)
live in water
shaped like a shoe
have complex organelles: contractile vacuole, mouth pore, anal pore
move using cilia
exhibits avoidance behavior
reproduces asexually (binary fission) or sexually (conjugation)
outer membrane-pellicle- is rigid and paramecia are always the same shape
ingests food through a mouth pore
Examples of Algae
Euglena (See Euglena Coloring Sheet )
live in water
have a flagella for movement
use chlorplasts for photosynthesis, but can turn into heterotrophs if they are kept in the dark
has an eyespot used for sensing light and dark
Spirogyra
live in water
multicellular
named after a spiral shaped chloroplast
autotrophic
Parasitic Protists
Parasite - an organism that lives on or in a host organism and causes harm to that organism
Vector - an organism that can carry a parasite, and infect other organisms
|
Disease |
Protist |
Vector (carrier) |
Symptoms |
Details |
|
Amebic Dysentery |
Ameba histolytica |
water |
diarrhea |
can get from tap water in some places |
|
Giardiasis ("beaver fever") |
Giardia |
water |
diarrhea, vomiting |
don't drink water from streams |
|
African Sleeping Sickness |
Trypanosoma |
tse tse fly |
uncontrolled sleepiness, confusion |
Only found in isolated areas
lives in blood |
|
Malaria |
Plasmodium |
anopholes mosquito |
fever, chills, death |
can be treated with quinine
lives in blood
results in millions deaths per year |
|
Toxoplasmosis |
Toxoplasma |
cats |
fetal death or brain damage |
pregnant women should avoid cat litter |
Malaria
|
The arrow points to the purplish colored protist (Plasmodium), the pinkish spheres are blood cells |
Anopheles moquisto taking a blood meal, this is how a human becomes infected with plasmodium and contracts Malaria |
|
This slide shows a blood smear of a person infected with trypanosoma. The protist is the purplish colored string-like things. They appear string-like due to a flagella. The reddish circles are blood cells. |
B = Protist, Giardia
A = flagella |
Questions for Thought
1. Does the United States have a responsibility toward treating and containing parasitic infections found in other parts of the world?
2. Why is controlling the vector important to control the disease?
3. One of the best ways to prevent many parasitic infections is to have a source of clean water. Why do you think many third world countries have more incidence of parasitic infection that other countries?
