BIO211: General Biology I

Presentation

Kingdom Protista
Nadim Mitri

Jenny Elia

Reem Taleb
Bayan Sabbagh
 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.
 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

 Protists have many

different shapes
 Most scientists
mold

agree that fungi,

ulva
plants, and animals
evolved from early
protists

Paramecium
 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 leftovers of other organisms
 Some use more than one way to get food
 Some produce food—they use chloroplasts
to produce food through
photosynthesis
 Finding Food:
 Heterotroph:organism that cannot
make own food
Some are decomposers—they get
energy by breaking down dead
organic matter
 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
 Sexual Reproduction:
 Requires two
parents
 Paramecium
sometimes
reproduce sexually
by a process called
conjugation
 Kinds of Protists:
 Algae:
 All algae 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.
 Amoebas:
 Soft, jellylike
protozoans
 Found in fresh and salt
water, soil, and in
parasites
 Move with
pseudopodia, which
means “false feet”
 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
 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
 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.
 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.
 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
 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.
 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.