Kingdom Protista- Chapter 20

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
• Protist is any organism that is not a plant,
  animal or fungus

3
Classification of Protists

• How they obtain nutrition
• How they move

4
Classification cont

• Protists are classified into 3 main groups
• 1. Animallike Protists - also called
  protozoa (means "first animal") -
  heterotrophs2. Plantlike Protists - also
  called algae - autotrophs3. Funguslike
  Protists - heterotrophs, decomposers, external
  digestion

5
Animal-like Protists

• Four Phyla of Animallike ProtistsClassified 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
B. Sarcodines

• moves 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
• reproducing by binary fission (mitosis)
• contractile vacuole - removes excess water
• can cause amebic dysentery in humans - diarrhea
  and stomach upset from drinking contaminated
  water

8
Amoebas in Action
9
C. Ciliates

• Cilia are small hairs surrounding the protists
  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.

http//biologycorner.com/bio1/paramecium_movement.
html
10
D. Sporozoans

• Sporozoans are animal-like protists that have
  part of their life cycle inside the cells of
  their hosts.
• The most important example is Plasmodium, the
  parasite that causes malaria. Malaria kills 1-2
  million people each year.
• Mosquitoes are part of the life cycle. They suck
  blood from infected humans, ingesting the
  sporozoans. The sporozoans undergo sexual
  reproduction in the mosquitos gut.
• When the mosquito bites another person, the
  sporozoans infect the blood and liver of the
  host. The parasites multiply asexually inside
  the red blood cells, destroying them as they
  leave.

11
Vector / Protist?
12
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 the Euglena, also have flagella for
  movement.
• Some, such as the diatoms, have calcium carbonate
  (chalk) or silica shells.

13
Multicellular Algae

• The multicellular algae are commonly called
  seaweed. They can be classified into red, brown,
  and green algae. All have chloroplasts, but the
  pigments in the chloroplasts 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.

14
Algae Blooms

• Algae blooms are the sudden growth of a large
  population of single celled algae. They occur
  near the coastlines, with the algae feed 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

15
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

16
Fungus-like Protists water slime molds

• Like fungi, they are heterotrophs they get food
  and energy from other organisms (live or dead).

17
More Fungus-like Protists

• The water molds include some of the worst plant
  diseases.
• Phytphthora infestans causes rot in plants. In
  the 1840s, 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.