Protists
Chapter 1, Lesson 4 UNIT C
Protists are a diverse group of organisms that live in water including freshwater
and salt water. They are mostly single celled but some are multicellular. Protists
are micro-organisms that don’t fit in other kingdoms.
Examples of multicellular protists: slime molds, sea weed
Examples of single-celled protists: Diatoms, Euglena, Chlamydomonas
Type of Protists:
1. Animal-Like Protists or Protozoa
Animal like protest obtain their energy by eating other organisms or
decaying parts of other organisms. Examples are paramecium,
and amoeba.
Ways how protozoa catch and eat other organisms
 Some groups of protozoa contain chemicals that recognize a particle of food
or organism when it is nearby. The protozoan ingests the food and breaks it
down to obtain energy.
 Some sweep rapidly sweeping bacteria into a groove-like mouth. For
example paramecium moves using thousands of strands of cilia.
 Some protozoa spread out and wrap around their food e.g amoeba. Amoeba
is also called false foot. Amoeba has flexible cells.
 Some protozoa swim with the help of one or more whiplike structure called
flagella.
 Some live as parasites e.g mosquito that carries parasite from human to
human and cause malaria.
2. Fungus-Like Protists also called decomposers
 Fungus-like protist absorb food/materials from their environment, such as
soil or other organisms. They break down dead organisms and other organic
matter to get energy
 Examples are mold.
What is mold? Mold refers to many organisms that produce a fuzzy-looking
growth. Examples are water mold, which forms a fuzzy growth on food. Slime
molds live on decaying plants on the forest floor. Plasmodial slime molds that
looks like a fine net or lace, is one giant cell with many nuclei.
3. Plant-like Protist also called algae.
A seaweed
 Algae get energy from sunlight. Algae contain chlorophyll, a green pigment
that is necessary to capture the sun’s energy. Algae also use water and
carbon dioxide from the air to and to transform energy and release oxygen in
a process called photosynthesis.
 Examples of single celled algae are diatoms, chlamydomonas and volvox.
What is plankton?
All organisms that drift in water are called plankton. Plankton include the
young of protest.
What is phytoplankton?
Plankton that perform photosynthesis are called phytoplankton (plantlike
plankton).
Give examples of phytoplankton.
Algae and cyanobacteria that live in oceans and produce most of the oxygen
animals need.
What are three ways protist get their energy?
There are three ways:
a. Capture sunlight and convert it to usable energy (plant-like protist)
b. Get energy from eating other organisms.
c. Some absorb energy from their environment (funguslike protest)
EUGLENA:
 Plant-like and animal-like
 Can do photosynthesis and consume food