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
