The kingdom Protista includes a diverse range of single-celled and simple multi-cellular eukaryotic organisms. While they differ greatly from one another, protists share characteristics of being eukaryotic with nuclei but less complex than other eukaryotes. Protists reproduce through both asexual and sexual means. They obtain food through photosynthesis, consuming other organisms or organic matter, or using multiple methods. Major groups of protists include algae, protozoa like amoebas and ciliates, slime molds, and diatoms.

1. Kingdom Protista

2. General Characteristics
 Protists are very diverse and have few
traits in common
 Most are single-celled organisms, but
some are many cells, and others live in
colonies
 Some produce own food, others eat other
organisms or decaying matter
 Some can control own movement, others
cannot

3.  Characteristics that protists DO share:
 Eukaryotic(have a nucleus), but are less
complex than other eukaryotic organisms
 Do not have specialized tissues
 Members of the kingdom Protista are
related more by how they differ from
members of other kingdoms than by how
they are similar to other protists

4. zooflagellates
 Protists have many
different shapes
Pretzel slime
 Most scientists
mold
ulva
agree that fungi,
plants, and animals
evolved from early
protists
Paramecium

5. Protists and Food
 Protists can get food many ways:
 Can make own food
 Can eat other organisms
 Can eat parts or products of other organisms
 Can eat remains of other organisms
 Some use more than one way to get food
 Some produce food—they use chloroplasts
to produce food through photosynthesis

6.  Finding
Food
Heterotroph: organism that cannot
make own food
Some are decomposers—they get
energy by breaking down dead
organic matter

7. Asexual Reproduction
 Most protists
reproduce asexually
 Offspring come from
just one parent
 Binary fission: a
single-celled protist
divides into two cells
 Each new cell is a
single-celled protist

8. Sexual Reproduction
 Requires two parents
 Paramecium
sometimes reproduce
sexually by a process
called conjugation

9.  Algae
Kinds of Protists
 Allalgae have the
green pigment
chlorophyll, which is
used to make food
through
photosynthesis
 Almost all algae live in
water
 Free-floating, single-
celled algae are called
phytoplankton, which
produce much of the
world’s oxygen

10.  Amoebas
 Soft,jellylike
protozoans
 Found in fresh and salt
water, soil, and in
parasites
 Move with
pseudopodia, which
means “false feet”

11.  Ciliates
 Have hundreds of cilia—
tiny, hairlike structures
 Cilia move the protist
forward by beating back
and forth—sometimes up
to 60 times a second!
 Cilia are also used for
feeding—they move the
food towards the protist’s
food passageway
 Best known of ciliates is
the Paramecium

12.  Spore-Forming Protists
 Many spore-forming
protists are parasites
 They absorb nutrients from
their hosts
 No cilia or flagella, cannot
move on their own
 Have complicated life
cycles that usually
includes two or more hosts
 Example: protist that
causes malaria uses both
mosquitoes and humans
as hosts

13.  Slime Molds
 Heterotrophic and can
only move during certain
periods of life cycle
 Look like thin, colorful
globs of slime
 Use pseudopodia to
move and eat fungi and
yeast
 When environmental
conditions are stressful,
slime molds grow stalks
with knobs, which contain
spores

14.  Red Algae
 Most of world’s
seaweed is red algae
 Most live in tropical
oceans
 Usually less than 1 m
in length
 Contain chlorophyll,
but have red pigment
 Red pigment allows
them to absorb light
that filters deep into
ocean

15.  Brown algae
 Most seaweed in cool
climates are brown
algae
 Attach to rocks or form
large floating beds in
ocean waters
 Have chlorophyll and
yellow-brown pigment
 Many are very large—up
to 60 meters

16.  Green algae
 Most diverse of protist producers
 Green because chlorophyll is main pigment
 Most live in water or moist soil
 Others live in melting snow, on tree trunks, and
inside other organisms

17.  Diatoms
 Single-celled
 Found in salt and fresh water
 Get energy from photosynthesis
 Make up a large percentage of phytoplankton
 Cell walls contain a glasslike substance called silica