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