Kingdom Protista
Kingdom Characteristics• Eukaryotic• Mostly unicellular (microscopic)
some are multicellular
• Autotrophic, Heterotrophic, and both• Most reproduce asexually, but some can use
conjugation (exchange of genetic material)• Cell wall may or may not be present• Taxonomic Misfits–
Contains all eukaryotic cells that can’t be classified as plant, animal or fungus
Evolutionary ImportanceProtists are considered to be the ancestors of
the three multicellular kingdoms—fungi, plant, animal
Major Divisions of ProtistsPlant-like Protists (Algae)Animal-like Protists (Protozoans)Fungus-like Protists (Slime Molds)
Plant-like Protists—AlgaeAutotrophicContain cell wallsMost are immobile—some are mobile
Examples of Plant-like Protists:Green, Red, and BrownAlgaeCellular Organization:
– Multicellular (Red and Brown) Green algae can be either
• Nutrition: Photosynthetic (Autotrophic)
Locomotion: Non-motile
Habitat: Red Algae: Marine Green Algae: Fresh, Marine, Soil Brown Algae: Marine
Classified by their pigment Green, Red, or Brown (kelp) Algae
Used in many foods such as pudding, jelly, jelly beans, ice cream, marshmallows, salad dressing
Diatoms• Cellular Organization:
– Unicellular• Nutrition:
– Autotrophic• Locomotion:
- Non-motile• Habitat:
– Fresh and Marine• Shells made out of silica (glass-like)
Euglenoids• Cellular Organization:
– Unicellular• Nutrition:
– Heterotrophic/Autotrophic• Locomotion:
- 1 or 2 Flagella• Habitat:
– Aquatic• Ex: Euglena
Animal-like Protists– a.k.a. Protozoans• Heterotrophic• All are unicellular• None contain cell walls• Most can move:– Cilia- hair-like projections– Flagella- whip-like tail– Pseudopod- “false foot”
Sarcodines- Ameoba• No cell wall gives them flexibility• Cellular Organization:
– Unicellular• Nutrition:
– Heterotrophic• Locomotion:
-Pseudopods• Habitat:
– Fresh and salt water• Some may cause disease (they are parasites)
Flagellates• Cellular Organization:
– Unicellular• Nutrition:
– Heterotrophic• Locomotion:
-flagella• Habitat:
-free living and parasitic• Ex: Trypanosomes causes AfricanSleeping
Sickness
Ciliates• Cellular Organization:
– Unicellular• Nutrition:
– Heterotrophic• Locomotion:
- cilia• Habitat:
- fresh water and marine• Ex: Paramecium, Vorticella and stentor
Sporozoans• Cellular Organization:
– Unicellular• Nutrition:
– Heterotrophic• Locomotion:
-Non-motile• Habitat:
-parasitic• Ex:– Plasmodium-Malaria
Fungus-like Protists- slime molds• Heterotrophic
decomposers• Contain cell walls• Multicellular• Exist in different
forms and produce spores
• Reproduce by forming spores
• 3 types:water molds, downy mildews, and slime molds
Slime Molds• Cellular Organization:
– Multicellular• Nutrition:
– Heterotrophic• Locomotion:
- amoeboid movement• Habitat:
- cool, moist, shady places
Watery/Downy Molds• Cellular Organization:
– Multicellular• Nutrition:
– Heterotrophic (either parasites or feed on dead organic matter)
• Locomotion: - amoeboid movement
• Habitat: -cool, moist, shady places
• Cause of the Irish potato famine in 1845-1850 that killed 1 million people
Ecological Importance of Protists
• Autotrophic protists are primary component of PHYTOPLANKTON
• They carry out 70 – 80% of the world’s photosynthesis
• They are the base of most of the world’s food chains
Negative Contributions of Protists
• Many cause disease– Malaria, sleeping sickness, amebic dysentery, etc.
• Responsible for “Red Tide” that poisons shell fish
• Algae blooms result in fish kills
Paramecian Fission (asexual)
Paramecium Conjugation Two individuals line up with each other and make
contact with their oral groove, The micronucleus (2N) undergoes meiosis result-
ing in four micronuclei in each of the two cells (N) 3 micronuclei degenerate and are digested by the
cell. The remaining micronucleus in each paramecium
divides once again, by mitosis. By the time this has occurred, most of the cell
membrane dividing the two cells is gone. The two halves (originally two cells) then exchange
one of their micronuclei. The cell membrane between the two halves gets
rebuilt and the two cells separate again. The two haploid micronuclei (one original and one
new) fuse into a single diploid micronucleus. The original macronucleus, disintegrates and gets
digested by the cell’s enzymes. The micronucleus divides by mitosis to produce
two identical diploid micronuclei in each individual.
One of the micronuclei then becomes the real micronucleus while the other one grows and becomes the new Macronucleus.
animation