1. 7.3 Protists
Key Concepts: What are the characteristics of animal-like, plantlike, and funguslike protists?
Key terms: protist, protozoan, pseudopod, contractile vacuole, cilia, symbiosis, mutualism, algae, spore

2. What is a protist?
Protists are eukaryotes that cannot be classified as animals, plants, or fungi.
Mostly it’s all the other stuff that aren’t those things.
They are extremely diverse.
Some unicellular, some multi, some autotrophs, some heterotrophs, etc
Divided into three categories:

3. Animal-like protists
Like animals, animal-like protists are heterotrophs, and are able to move around to get food.
Protozoans (animal-like protists)
Unicellular
4 kinds – pseudopods, cilia, flagella, parasites

4. Protozoans continued
Protozoans that live in fresh water, like amoebas, have a problem:
Small particles, like water, pass through the cell membrane into the cytoplasm
So what?
If excess water builds up inside the cell, the amoeba could BURST
So they have contractile vacuoles – a structure that collects excess water and expels it (like you and your bladder)

5. Protozoans continued
Some have symbiosis – a close relationship in which at least one of the species benefits
Some have mutualism – where both partners benefit from living together

6. Protozoans with Pseudopods
Pseudopods – temporary bulges of the cell – means “false foot”
The pseudopods form when cytoplasm flows to one location
Examples: sarcodines and amoebas

7. Protozoans with cilia
Ciliates – have structures called cilia (hairlike projections from cells that move with a wavelike motion)
They are used to move and obtain food
Paramecia
Use two contractile vacuoles
More than one nucleus

8. Protozoans with flagella
Flagellates – protists that use long, whiplike flagella to move. May have more than one.
Some of them live inside bodies of other organisms

9. Protozoans that are parasites
These are characterized more by the way they live than by the way they move
They are all parasites that feed on the cels and body fluids of their hosts
They move in a variety of ways
Sometimes have more than one host

10. Plantlike Protists Commonly called algae – they are autotrophs
Play a significant role in many environments by creating food and oxygen
Vary in size
Some unicellular, others multicellular, usually live in colonies
Come in a wide variety of colors

11. Diatoms
Unicellular protists with beautiful glasslike cell walls. Some float near the surface of lakes or oceans, others attach to objects like rocks
Food source for heterotrophs
When they die, their cell walls collect on the bottoms of bodies of water and create diatomaceous earth.

12. Dinoflagellates
Unicellular algae surrounded by stiff plates that look like a suit of armor
Have different amounts of green, orange, and other pigments
ALL have two flagella held in grooves
Twirl like tiny tops
MANY glow in the dark

13. Euglenoids
Green, unicellular algae that are found mostly in fresh water
CAN be heterotrophic under certain conditions (usually autotrophs when enough light is present)

14. Red Algae Almost al red algae are multicellular seaweeds
Red pigment good at picking up small amounts of light
Used in a variety of ways by people (e.g. dyes)

15. Green Algae Green algae contains green pigments. Most unicellular
Some form colonies
Most live in fresh water or sea water
Closely related to plants and use chlorophylls
Some people think they should be in the plant kingdom, but they ain’t right now

16. Brown Algae “seaweeds” Has a lot of plantlike structures
Flourish in cold waters
Form forests underwater
Often have gas filled sacs called bladders that allow them to float upright

17. Funguslike protists
Your book refers to them as the “sort of like” organisms
As in, they are sort of like all kinds of things.
They are heterotrophs
They have cell walls
Most have spores – tiny cells able to grow into new organisms – to reproduce

18. Slime molds Often brilliantly colored, live in dark moist places
Eat bacteria and other microorganisms
Begin as tiny cells, use pseudopods to creep around
Join together and grow to form a big jelly mass
Release spores to make new slime molds

19. Water molds and downy mildews
Most water molds and downy mildews live in water or moist places
Grow as tiny threads that look like fuzz
Attack food crops