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