Kingdom Protista
The garbage can kingdom
The kingdom
• The kingdom Protista
– Has 115,000 different species (diverse)
– Most (but not all) are unicellular
• Multicellular algae is the rule breaker
– They are all eukaryotic (they have a nucleus)
– They can live as solo organisms or can be in
groups called colonies
– They can be decomposers, autotrophs, and
heterotrophs
Who is Older?
• We think that bacterial organisms
(prokaryotes) were the first living
organisms, but when did protists arrive?
• Fossil evidence shows bacteria to be
approximately 3.5 billion years old
• Protista life is estimated to be
approximately 1.5 billion years old
• This means that the evolution of the
nucleus took approximately 2 billion years
Where Did it Come From?
• With such a vast amount of time as 2
BILLION years, the question must be
asked:
Remember the Endosymbiotic
• Theory has it that just as the mitochondria
and chloroplast may have originated as
prokaryotic life, so may the nucleus and
other organelles
• The idea is that a large prokaryotic
organism engulfed smaller prokaryotes,
• But rather than eating them, it allowed
them to live within it as symbiotic
organisms
• Over time, the organisms became
specialized, and required the others to
survive… they became:
More than once?
• Some scientists believe that this
endosymbiosis may have occurred more
than once
• Because of the diversity in the Protista
kingdom, it makes sense to think this may
have occurred up to three separate times
at least
Why?
• There are autotrophic bacteria -> there are
plant-like protists
• There are heterotrophic bacteria -> there
are animal-like protists
• There are bacteria that break down dead
and decomposing organic matter -> there
are Fungus like protists
Animal-like Protista
• The heterotrophic, single celled
eukaryotes are called animal-like protists
• These organisms are generally grouped
by their means of locomotion
Ciliophora
• Members of the phyla Ciliophora are animal like
protists that use cilia by means of locomotion
• Cilia are finger like projections that act like
miniature oars and paddles that propel the
ciliates through water
• They are found in both fresh and saltwater
• Ciliates use an organelle called a contractile
vacuole to expel excess water
• They have a small gullet area where food is
taken in, placed into a food vacuole, and later
brought to a lysosome for digestion
Ciliophora
Zoomastigina
• The Zoomastigina phylum consists of
animal-like protists that move by means of
a flagella
• A flagella is a whip-like structure that
propels and organism through the water
– Flagella will either whip back and forth or spin
like a boat propeller
• They may have one or many flagella
• They absorb food through their
membranes
Zoomastigina
Sporozoa
• Members of the phylum Sporozoa are
sessile (non-motile), meaning they don’t
move
• They are ALL parasitic
• Many have complex life cycles involving
multiple hosts
• They reproduce by means of spore
production which attach to the host
parasitically
Sporozoa
Sarcodina
• The animal-like protists that belong to this
phylum have pseudopodia
• Pseudopodia (literally meaning “false foot”
are used for locomotion and engulfing food
• A pseudopod behave similar to what
science fiction calls a blob
• They also use contractile vacuoles to push
water through their cell membrane
allowing movement
Sarcodina
Trichonympha
Termite symbiosis
Plant-like Protists
• All members of the Plant-like protists are
single celled (except multicellular algae)
eukaryotic autotrophs
• They also are often grouped by
locomotion
Euglenophyta
• The members of the phylum Euglenophyta
are all Flagellates (they have flagella)
WITH CHLOROPLASTS
• Many of these organisms are both
autotrophic and heterotrophic depending
on the availability of sunlight
• Euglena is the staple member of this phyla
Euglenophyta
Pyrrophyta
• The members of the phylum Pyrrophyta are
generally called “fire protists”, and are commonly
called dinoflagellates
• Most are autotrophic, but a few members have
lost their chloroplasts and are now completely
heterotrophic
• They move by means of 2 flagella
• They often have a thick protective shell, giving
them an odd shape
• They cause RED TIDES
Dinoflagellates
Red Tides
Chrysophyta
• Members of the phylum Chrysophyta are
called the golden protists or even more
commonly, the diatoms
• Diatoms tend to produce thick, shell-like
cell walls that contain silicon, giving them
a glass appearance
• Often times these appear like glass boxes
under a microscope
• They are used in many fine jewelry
cleaners
Diatoms