CHAPTER 3 PROTIST BIOLOGISTS ONCE CLASSIFIED THESE ORGANISMS

CHAPTER 3: PROTIST

• BIOLOGISTS ONCE CLASSIFIED THESE ORGANISMS IN THE KINGDOM PROTISTA BUT IT IS NOW CLEAR THAT THESE ORGANISMS BELONG IN MULTIPLE GROUPS WITHIN THE DOMAIN EUKARYA. • THE EVOLUTIONARY HISTORY OF THESE ORGANISMS IS STILL UNCERTAIN AND IS CONTINUOUSLY CHANGING DUE TO NEW DISCOVERIES.

PROTISTS OBTAIN THEIR NUTRIENTS A NUMBER OF WAYS

ONE CURRENT HYPOTHESIS OF THEIR ORGANIZATION • GROUPS ALL EUKARYOTIC ORGANISMS INTO FOUR “SUPERGROUPS” • SAR • EXCAVATA • UNIKONTA • WHICH CONTAINS FUNGI AND ANIMALS • ARCHAEPLASTIDA • WHICH INCLUDES LAND PLANTS

• THE TERM PROTIST IS STILL USED TO REFER TO EUKARYOTIC ORGANISMS THAT ARE NOT PLANTS, FUNGI, OR ANIMALS. • SO THEY ARE ACTUALLY SPREAD THROUGHOUT THE FOUR SUPERGROUPS

SAR SUPERGROUP • “SAR” STANDS FOR THE THREE CLADES WITHIN THE SUPERGROUP • STRAMENOPILA, ALVEOLATA, AND RHIZARIA WHICH ARE EXTREMELY DIVERSE

CILIATES • WE WILL ONLY COVER CILIATES IN THIS LAB • CILIATES MOVE BY THE USE OF CILIA, WHICH MAY COVER THE ENTIRE CELL SURFACE OR MAY BE ARRANGED IN ROWS OR TUFTS.

View paramecium under the microscope * *

Sexual Reproduction: Conjugatio n Asexual Binary Reproduction: Fission

EXCAVATA SUPERGROUP

• EXCAVATA IS A DIVERSE GROUP OF UNICELLULAR PROTISTS THAT • HAVE FLAGELLA • ARE NAMED AFTER A DEEP OR “EXCAVATED” ORAL GROOVE • HAVE HIGHLY MODIFIED MITOCHONDRIA

EUGLENA IS A MIXOTROPH

* TRYPANOSOMA IS PARASITIC View Trypanosoma under the microscope. * *

UNIKONTA SUPERGROUP UNIKONTA IS COMPOSED OF AMOEBOZOANS, PLASMODIAL/CELLULAR SLIME MOLDS, CHOANOFLAGELLATES, FUNGI, AND ANIMALS.

* • AMOEBOZOANS MOVE AND FEED BY LOBESHAPED PSEUDOPODIA (FALSE FEET) THAT FORM AS TEMPORARY EXTENSIONS OF THE CELL. • VIEW AMOEBA PROTEUS UNDER THE MICROSCOPE. *

ARCHAEPLASTIDA SUPERGROUP ARCHAEPLASTIDA INCLUDES RED ALGAE, GREEN ALGAE, AND LAND PLANTS. THESE ARE CLASSIFIED TOGETHER DUE TO THE PRESENCE OF CHLOROPLASTS BOUNDED BY INNER AND OUTER MEMBRANES.

* VIEW VOLVOX UNDER THE MICROSCOPE

To Do List: (Protists) • Observe protist slides • Label important features • Know which Supergroup each example belongs CLEANUP: • Organize slides in order • Store microscope with light switch off, stage all the way down, and on the 4 X objective. • Points will be docked if you and/or your group do not cleanup and organize your station before you leave the lab room.