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AP Biology
Protista
Chapter 22
2007-2008
Domain Bacteria
Domain Archaea
Domain Eukarya
Common ancestor
Kingdom: Protists
Domain Eukarya
General Characteristics
Classification criteria
eukaryotes
not animal, plant or fungi
Great Diversity
Problems with Protist Classification Too Diverse!
doesn’t reflect any evolutionary relationship amongst all kingdom members
paraphyletic
Theory of Endosymbiosis
Ancestral eukaryotic cell Eukaryotic cell with mitochondrion
internal membrane system
aerobic bacterium
mitochondrion
chloroplast
Eukaryotic cell with chloroplasts
photosynthetic bacterium
Paramecium
& symbiont
Chlorella
Protist Diversity
The full spectrum of modes of life
from unicellular to multicellular
autotrophic to heterotrophic
asexual to sexual reproduction
pathogenic to beneficial
sessile to mobile
Mobility
How Protists move
flagellum
cilia
pseudopod
Protist Diversity Animal-like Protists
heterotrophs, predators Amoeba Paramecium Stentor Paramecium with food
vacuoles stained red Amoeba ingesting a Paramecium
Foraminiferans and Radiolarians
Heterotrophic single cells with chalky or glassy shells live in great numbers in the world’s oceans; cytoplasm extends through many pores
Protist Diversity
Plant-like Protists
autotrophs, photosynthesis Euglena
algae
diatoms
Euglena
Diatoms
Multicelled
Brown algae
Used as thickeners
Food
Fertilizer
Herbal supplements
Protist Diversity Parasitic & pathogenic Protists
malaria Giardia trypanosomes
Plasmodium
Giardia
Trypanosoma
The Malaria Menace
Plasmodium, a single-celled protist, causes malaria – but also manipulates its mosquito and human hosts to maximize its own survival
Giardia
Intestinal parasite
Trichomonas vaginalis
STD
Protist Diversity
Beneficial & necessary Protists
phytoplankton small algae + diatoms
much of the world’s photosynthesis
produces ~90% of atmospheric oxygen
zooplankton heterotrophic protists + animals
key ecological role at base of marine food web
Dinoflagellates
Some are predators / parasites
Some are photosynthetic
Some are bioluminescent
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