Friday February 5, 1999
Announcements:

Lecture notes:

This class has a lot of membranes that have importance in our lives:
1. Some infect us.
2. Some poisons us.
3. Some infect/infest/poison our pets, livestock and property.
4. Some are photosythetic.
5. Some provide useful products.
6. They are invaluable in the food chain.

Protista: Main Characteristics

Mostly single celled, some multicelled membranes.
Some are photosythetic.
Some are heterotrophic.

* There are many arguments about the bouinderies of the Kingdom.
** The members sometimes form aggregates which are multicelled - which further confuses the issue.

Red Algae ( both Red and Brown Algae are "Seaweeds")
Brown Algae
* Algin comes from brown species.
* Agar comes from one red species.
* They all have chlorophyll, but other pigments mask the color.

Green Algae
* are most similar to land plants.
* They have cholroplasts.
* They store carbohydrates as starch and have cellulose reinforced cell walls.

* There are a few single-celled members.

Slime Molds*
1. All are heterotrohs.
2. They form masses that differentiate into spore bearing structures.
a. Cellular slime molds - aggregates of distinct cells.
b. Plasmodial slime molds - cell walls disappear and form a multicelled mass of cytoplasm.
3. Some form spores which can be dispersed by air currents.
4. Some can creep about and engulf food.
5. Habitat is smmonly decaying matter on the forest floor.
Example: Dictyostelium discoideum (cellular type)

Chytrids*
1. Most are saprophytes (some parasites)
2. Some are single celled.
3. They live in water or mud.
4. Reproduction is by asexual production of spores.
5. These spores are motile.

Water Molds*
1. Most are saprophytes (some parasites)
2. Important aquatic decomposers.
3. Reproduction: hyphae differentiate into gametangia and produce male or female gamates. The gamates
form a resting spore if conditions are not favorable for growth.
4. These spores are motile.
Example: white mold on aquarium fish. Powdery mildew on grapes. Potato blight.

* formerly grouped into the Fungi Class

Euglenids
1. Found in ponds and lakes.
2. They true flagella.
3. They are photosynthetic. Some can be heterotrophs, excess food.
4. They have a pellicle - a thin transparent body covering. No cellulose cell wall.
5. They have an eye spot which contains carotenoid pigments and is light sensitive. It is used to locate good light sources
and position the cell for photosythesis.
Example: Euglena or plant/animal dilemma.

Chrysophytes
1. Fresh and slat water habit.
2. Photosynthetic.
3. All have other pigments that mask the color of chlorophyll.
4. Some have flagella, diatoms don't.
5. Some have silica shells or scales. These organisms literally live in glass houses. Others have calcium carbonate shells
like sea shells
Examples: golden algae, yellow-green algae, diatoms (diatomaceous Earth)

Dinoflagellates
1. Live in salt water. (marine environment) (mostly)
2. They all have flagella.
3. Most are photosynthetic. (a few are heterotrophic)
4. They may have other pigments that make them appear other colors.
5. Most are present in marine "plankton". (plankton means to wander) Plankton includes aquatic protistans and animal
larve that drift or swim weakly in the water. They are a major link in the food chain.
6. One type produces a neurotoxin that is poisonous to man and to fishes. When is infect mollusks, they are not affected
by the neurotoxin - BUT, people who eat the mollusks are - some die. When there red dinoflagellates over grow they
create what is called "The Red Tide".
7. The covering of many is composed of cellulose plants.

Protozoans
1. Protozoan means first animal.

2. There are 65,00 species - many of which are parasites. (Fewer that two dozen cause disease in humans)
3. Protozoans are grouped according to their means of locomotion.
4. None are photosythetic.

Flagellated
There are free living and parasitic forms.

Examples: Trypanosoma brucei-Causes African Sleeping Sickness which is transmitted via an insect "vector", the tse tse
fly.
Trichomonas vaginalis-a sexually Transmitted Disease
Giardia intestinalis- Infects the gut. Cysts contaminate the water supply. It is estimated that 10% of the USA
is probably infected.

Amoeboid
All use a pseudopod for locomotion or for feeding.

Example: Entamoeba histolytica causes amoebic dysentary.

Sporozoan
All are parasites.

They have a spore-like stage in the life cycle.

Many need vectors to transmit the spores to the host during part of the life cycle.

Example: Plasmodium - Four of this group cause malaria in humans and birds.

Ciliated
Most members of this class are predators.

The cilia are used for locomotion and sometimes to store toxins for protection or for feeding behavior.

Example: Paramecium