1. PROTISTS

2. What is a Protist?
Protists are eukaryotes that cannot be classified as animals, plants, or fungi
Recall: Eukaryotes have a nucleus and membrane-bound organelles
All protists live in moist surroundings
Protists=diversity
Examples of this
1) Some are unicellular while others are multicellular
2) Some are heterotrophs, some autotrophs, some both
3) Some cannot move while others move extremely fast

3. What is a Protist?
Due to this diversity, classifying these organisms has been extremely difficult
Scientists have decided to classify them into the following 3 groups:
Animal-like protists
Plantlike protists
Fungus-like protists

4. Nutrition
Many protists are autrophs, organisms that make their own food.
Other protists are heterotrophs, organisms that must get their food by eating other organisms or their byproducts

5. Movement and Reproduction
Protists use cilia, flagella, or pseudopodia to move.
Reproduction is done either sexually, asexually, or both.
They reproduce asexually by binary fission and sexually by conjugation

6. Animal-Like Protists Heterotrophs
Most can move from place to place to obtain food
Animal-like protists are also called protozoans
Unicellular
Protozoans can be classified into four groups, based on the way they move and live:
Protozoans:
With Pseudopods
With Cilia
With Flagella
That are parasites

7. Protozoans With Pseudopods
Protozoans with pseudopods are known as sarcodines
Sarcodines move and feed by forming temporary bulges in the cell-cytoplasmic streaming
Pseudopod=false foot
Pseudopods form when cytoplasm flows toward one location and the rest of the organism follows

8. Protozoans with Pseudopods
Pseudopods enable sarcodines to move and trap food
Some fresh-water sarcodines have a contractile vacuole
A structure that collects the extra water and then expels it from the cell
Ex) Amoeba

10. Protozoans with Cilia Known as the Ciliates
Use cilia, hair-like projections from cells, to move and obtain food
Act like tiny oars
Cells are complex
Example
Paramecium

11. Paramecium Paramecium are a ciliate that: Has two contractile vacuoles
Has two nucleus
Large nucleus controls the cell
Small nucleus functions in reproduction
Reproduce mostly by binary fission but occasionally by conjugation

13. Protozoans with Flagella
Called the flagellates
Protists that use long, whiplike flagella to move
May have one or more flagella
Some live inside other organisms (symbiosis)
Others may harm its host it is in

14. Protozoans That Are Parasites
This group is characterized more by the way they live than their movements
They are all parasites that feed on the cells and body fluids of their host
Move in a variety of ways
Many have more than one possible host
Ex)
Plasmodium: protist that causes malaria

16. Plantlike Protists Commonly called algae Extremely diverse
Like plants, they are all autotrophs
Most are able to use the sun’s energy to make their own food
Some are unicellular while others may be multicellular

17. Plantlike Protists
Some live in colonies of a few cells up to thousands of cells
Wide variety of colors depending on their pigments
Green, yellow, red, brown, orange, or even black
Play a significant role in many environments

18. Diatoms Unicellular protists with glasslike cell walls
Some float near the surface of water bodies while others attach to rocks in shallow water
Can move by oozing chemicals out of slits in their cell walls and glide in the slime
When they die, there cell walls collect on the bottom of oceans or lakes to form diatomaceous earth
Diatomaceous earth is used in household scouring products, insecticides, and as a polishing agent

20. Dinoflagellates
Unicellular algae surrounded by stiff plates that look like a suit of armor
Variety of colors
All have two flagella held in grooves between their plates
When flagella beat, they twirl like toy tops as they move through the water
They glow in the dark

22. Euglenoids Green, unicellular algae found mostly in fresh water
Can be heterotrophs under certain conditions but mainly autotrophs
Consists of a flagellum, a nucleus, chloroplasts, eyespot (used to find light for photosynthesis)

23. Structure of a Euglena

24. Characteristics of Algae
Algae can be unicellular, colonial, filamentous, or multicellular
Seven Phyla of Plant-like protists:
Chlorophyta
Bacillariophyta
Euglenophyta
Phaeophyta
Rhodophyta
Dinoflagellata
Chrysophyta

25. Red Algae Almost all are multicellular seaweeds
Found as deep as 260 meters; red pigment good for absorbing sunlight at low depths
Substances extracted from red algae is used to make ice cream and hair conditioner

26. Green Algae Very diverse
Most are unicellular; some form colonies; others are multicellular
Most live in either fresh or salt water
Few live on land on rocks, crevices in tree bark, or in moist soils
Very closely related to plants; contain same type of chlorophyll

27. Green Algae

28. Brown Algae Many organisms commonly called seaweed is brown algae
Has plantlike structures
Giant kelps are an example of brown algae
Some substances in brown algae are used as thickeners in puddings and other foods

29. Funguslike Protists Fungus are the “sort of like” organisms
Heterotrophs like animals; cell walls like plants
Spore is a tiny cell that is able to grow into a new organism
Have the ability to move at some time in their lives

30. Slime Molds Brilliant colored
Live on forest floors and other moist, shady places
Feed on bacteria and other microorganisms
Produce spores when conditions become harsh

31. Water Molds and Downy Mildews
Both usually live in water or moist places
Grow as tiny threads that look like fuzz
Attack many food crops