Biology-Mr. Willets
Protist Kingdom- Protozoans
The Protist Kingdom consists mostly of two basic types of organisms- the algae and the protozoans. Algae are the autotrophic protists and were once in the plant kingdom. Protozoans are the heterotrophic protists and were once in the animal kingdom (protozoa means "first animals"). A third group of organisms are also in the protist kingdom- the slime molds. These were once in the fungi kingdom. Because protists are mostly unicellular, they were considered too simple to be plants, animals or fungi and they were moved into their own kingdom. All protists are eukaryotic and so are more complicated than the other unicellular organisms- the bacteria.
In general, protozoans have certain characteristics.
a) they are all heterotrophic
b) they are all unicellular
c) they all reproduce by binary fission
d) most use conjugation for genetic recombination
e) many live in fresh water and therefore require a contractile vacuole
f) some can form protective covers during harsh conditions- these are called cysts
g) many live by drifting in the water- any heterotroph that drifts in water is called zooplankton
(zoo = animal plankton = drifter)
h) There are 4 phylums of protozoans based on how they move
Phylum Sarcodina- the members of this phylum move by changing shape.
a) example- ameba (Amoeba is the genus name, ameba is the common name)
b) the outer part of the cytoplasm is called ectoplasm and is gel-like. This makes the outer edge of the cell somewhat rigid. The inner part of the cytoplasm is called the endoplasm and is more sol-like. It moves around inside the cell causing the change of shape.
c) as the ameba changes shape, pseudopods ("false feet") form and disappear. These pseudopods can
surround food- phagocytosis.
d) some sarcodines have shells- in the past, after dying, these shells went to the bottom of the ocean and formed into rocks. Rocks of this type were used to build the pyramids.
e) some sarcodines are human parasites-ex. amebic dysentery produces a bad case of diarrhea
Phylum Ciliophora- the members of this phylum move using cilia- they are called ciliates
a) example-paramecium-this is the most complicated of the protozoans
b) some are parasites
Phylum Zoomastigina- the members of this phylum move using flagella. They are called flagellates.
a) Many are parasitic- ex. Trypanosomes cause sleeping sickness (vector is the Tsetse fly)
They damage brain cells which puts victims into a coma (confused with being asleep)
b) Some kinds live in the gut of termites and help them to digest wood. This is a symbiotic relationship.
c) one kind - called euglenoids- are autotrophic and heterotrophic- in light they make food, in
darkness they absorb food. Some books put these with the algae, others put them with the
protozoans. Some books do both. These organisms have eyespots- structures that detect light.
Euglena is an example of this type of organism.
Phylum Sporozoa- the members of this phylum do not move. They live in a host and are carried to new hosts by vectors
a) Sporozoans are all parasites ex. Plasmodium causes malaria (vector- female anopheles mosquito)
Plasmodium destroys red blood cells and releases toxins which cause fever and chills.
b) Sporozoans reproduce using spores- hence the name.
Questions-
1) Bacteria and protists are mostly unicellular. Why are they not in the same taxonomic group?
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2) Which protists were once considered to be animals? _______________ Why ? _______________________________________________ Why are they no longer put in the animal kingdom? _____________________________________________.
3) Which protists were once considered to be plants? __________ Why? ____________________
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4) Slime molds are protists that were once put into which kingdom? __________________
5) Conjugation is a method of______________________________. This can produce organisms better able to ________________
56) As do all unicellular organisms, protozoans reproduce by ___________________
7) What does the word "protozoan" mean? _____________________________
8) Which protozoans would require a contractile vacuole? _____________________________
What does a contractile vacuole do ? _____________________________________________
This is necessary because fresh water is a ___________________ solution (who remembers this?)
9) In a lake around here, when would an ameba form a cyst? ______________________________
10) Zooplankton are organisms that are ______________________ and _______________ in the water. (What do you suppose phytoplankton are?)
11) The ameba is a member of what phylum? _________________________ These organisms move by __________________________ These organisms feed by ____________________ their food. This is called __________________________
12) The "false feet" of the ameba are called __________________________
13) A disease caused by certain amebas is ________________________________
14) The shells of certain sarcodines formed into _______________________ (the chalk I use may have come from this type of rock)
15) Members of Phylum Ciliophora are called _________________. They move using __________
An example of a ciliate is ______________________
16) Phylum Zoomastigina contains the __________________ which move using ______________
17) Trypanosomes are ____________________ that can cause disease. What disease do they cause? __________________________ What is the vector of this disease? _____________________
18) Some flagellates have a symbiotic relationship with what organism? _____________________
How do these flagellates help? ___________________________________________
19) Euglenoids can be considered algae because they can ______________________________ When do they do this? ________________________. What do they have to help them do this ? __________________ Why are they also considered to be protozoans? ___________________
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20) Sporozoans do not need to move to find food. Why not? _______________________________
They do not need to be able to move to get to a new host. Why not? ___________________________
21) What cells in your body does Plasmodium destroy? __________________ What does it release to hurt you? _________________ What disease does Plasmodium cause? _______________
22) What is the vector of malaria? _____________________________________ (it is not the male because only the female ________________)