Lecture 21: Protists

Question 1

Monophyletic group (Clade)

Answer 1

Group that includes an ancestor and all of its descendants and only those descendants
-can be isolated by one cut on the tree

Question 2

True or false: Eukaryotes are complex archaea

Answer 2

True

Question 3

The endosymbiotic theory

Answer 3

Aerobic bacterium entered proto-Eukaryote then Cyanobacteria entered proto-plant cell

Question 4

Most eukaryotes are…

Answer 4

Microbes and “Protists”

Question 5

Excavates

Answer 5

•Evolutionary relationships not well resolved
•Possibly the earliest diverging lineages of eukaryotes
•Discoba, Metamonada, Malawimonadida

Question 6

Discoba

Answer 6

•Contains Euglenozoa and other phyla
•Euglenozoa contains photosynthetic as well as parasitic flagellates (Trypanosoma- African sleeping sickness)
•Photosynthetic eugenics have a secondary plastid

Question 7

Metamonada

Answer 7

•Anaerobic organisms, many lack mitochondria (lost secondarily)
•Free living, mutualistic (in guts of wood-eating insects), or parasitic (Trichomonas, Giardia)

Question 8

Amorphea

Answer 8

•Heterotrophic organisms
•Contains fungi and animals (Opisthokonta)
•Also contains other phyla and Amoebozoa (one of the amoeboid groups plus some slime molds)

Question 9

Amorphea-Amoebozoa

Answer 9

•Free-living or parasitic
•Amoebas and (some) slime molds

Question 10

Amorphea-Slime molds

Answer 10

Growth cycle:
Unicellular growth—>Multicellular development

Question 11

Archaeplastida

Answer 11

•Mostly photosynthetic organisms with a primary plastid (chloroplast, rhodoplast, or cyanelle)
•Plastids likely come from a single cyanobacterial ancestor

Question 12

Archaeplastida-Rhodophyta (red algae)

Answer 12

•Unicellular or multicellular, contain chlorophyll a, carotenoids, as well as phycoerythrin and phycocyanin
•Intertidal to deep sea; some freshwater
•Many marine seaweeds with complex life cycles and large, multicellular thalli (bodies)
—Nori
—Agar-agar, carrageenan

Question 13

Archaeplastida—Chlorophyta and streptophyta (green algae)

Answer 13

•Mostly photosynthetic (but also a few parasitic heterotrophs).
•Marine, freshwater, and terrestrial
•Many unicellular lineages, but also some colonial, coenobial, and complex multicellular thalli.
•Streptophyta include land plants
•Plastids (chloroplasts) contain chlorophylls a and b, as well as carotenoids

Question 14

Cryptista and Haptista

Answer 14

•Some photosynthetic, some not
•Secondary plastids of rhodophyte origin, nucleomorph (Cryptophyta)
•Important in ocean and freshwater plankton
•Haptophyta-calcareous exoskeleton; chalk deposits on ocean bottoms

Question 15

The TSAR supergroup

Answer 15

•Unicellular and multicellular forms
•Diversity of cell wall materials and exoskeletons
•Ecologically important-Primary producers, parasites
•Endosymbiosis gone wild

Question 16

TSAR—Stramenopila part 1

Answer 16

•Several photosynthetic groups, plus parasitic oomycetes
•Mostly secondary plastids of red algal origin, chlorophylls a and c
•Often called “heterokonts” because of two flagella of uneven length

Question 17

TSAR—Stramenopila part 2

Answer 17

•Diatoms-microscopic, just about any aquatic habitat, can form harmful blooms
•SiO2 (glass) cell wall; many species recognizable in the fossil record

Question 18

TSAR—Stramenopila part 3

Answer 18

•Oomycetes—fungal-like because of lateral gene transfer
•Phytophthora-potato blight
•Parasites of salamander eggs and others

Question 19

TSAR—Alveolata-Ciliates

Answer 19

•Have cilia (short, undulating flagella-like structures) on cell surface
•Freshwater or marine
•Some have symbiotic algae; most heterotrophic

Question 20

TSAR—Alveolata-Apicomplexa

Answer 20

•Heterotrophic but have a vestigial plastid (apicoplast)
•Plasmodium (malaria) , Toxoplasma, and other parasites

Question 21

TSAR—Alveolata-Dinoflagellates

Answer 21

•Freshwater and marine plankton
•Photosynthetic, mixotrophic, parasitic, mutualistic
•Some produce neurotoxins, harmful algal blooms, red tides
•Complex life cycles
•Nucleus-dinokaryon, condensed chromosomes; nucleic proteins of viral origin instead of histones

Question 22

Several endosymbiotic events in dinoflagellates

Answer 22

—Secondary, Tertiary, and kleptoplastidy
—Most-chlorophylls a and c (but depends on plastid origin); dinoxanthin, peridinin