Protists

Protists are a range of organisms that have many
different features. This makes them really hard to
classify.
Protists
While protists range significantly they do share common
characteristics:
1.
Most are unicellular
2.
May be autotrophic or heterotrophic
3.
Cells are eukaryotic and have membrane bound nucleus,
vacuoles, and mitochondria
4.
Cells reproduce asexually by binary fission (some through
sexual reproduction)
5.
Cells thrive in moist environments (such as fresh water, salt
water, animal fluids)
Protists
Examples
Organizing Protists
3 Categories:
1.
Animal-like Protists
2.
Fungus-like Protists
3.
Plant-like Protists
Examples
amoeba, paramecium,
malaria
1. Animal-like Protists
(a.k.a. Protozoa)

Are all heterotrophic

Capable of moving in
order to feed

Uses pseudopod to
grab food and move
Various methods of
locomotion
1. Cilia
2. Flagella
3. Pseudopod
* Parasitic
E.g. 1 Amoeba (Phylum: Cercozoa)
Surface is a cell membrane (flexible)
 Use temporary extensions known as pseudopodia (false
feet) to feed and move
 Live in moist environments
 Intestinal parasite amoebas can be contracted through
contaminated water

E.g. 2 Paramecium (Phylum:
Ciliophora)

Contain many cilia (for feeding and
locomotion)

Food in brought in through the oral groove
E.g. 3 Trypanosoma (Phylum: Zoomastigina)
This phylum has one or more flagella
 Causes the sleeping sickness

E.g. 4 Plasmodium (Phylum:
Sporozoa)

Plasmodium is the bacteria that causes malaria
in humans

Infects both humans and mosquitos

When a human is infected with malaria, a
mosquito that bites that human will also carry
malaria.

When the malaria carrying mosquito bites
another human, the human is now infected.
2. Fungus-like Protists

Known as slime moulds or water moulds

They like cool, shady, moist places

Are heterotrophic decomposers

Have cell walls

Can move at one point in their life
3. Plant-like Protists
•
•
They contain chlorophyll (used in photosynthesis)
They are autotrophic when light is present (in darkness
they are heterotrophic).
E.g. Euglena
•
•
Contains an eyespot (for detecting light) and a flagellum
(for propelling through water)
Has a pellicle instead of a cell wall
(is more flexible for movement)
3. Plant-like Protists
Other examples
include:
•
Dinoflagellate
•
Green Algae
•
Red Algae
•
Brown Algae
3. Plant-like Protists
Why are algae important?

They are primary producers (they make sugar
and oxygen essential for aquatic organisms)

Without them all fish would die

Algae also produce oil and are used as fertilizer

Algae can also cause harm: Too much algae can
block sunlight from water, and “sufficate” the
lake.
Homework
Read pages 72-78.
#19-21, 23 (p.76)
#2-4, 7-8, 10, 12 (p.78)