1. ADDITIONAL PROTISTS NOTES
CH. 16

2. The eukaryotic cell probably originated as a community of prokaryotes
Eukaryotic cells evolved from prokaryotic cells more than 2 billion years ago
The nucleus and endomembrane system probably evolved from infoldings of the plasma membrane.
Mitochondria and chloroplasts probably evolved from aerobic and photosynthetic endosymbionts, respectively.

3. A model of the origin of eukaryotes
Cytoplasm
Ancestral prokaryote
Plasma membrane
Endoplasmic reticulum
Nucleus
Nuclear envelope
Cell with nucleus and endomembrane system
Membrane infolding
Aerobic heterotrophic prokaryote
Ancestral host cell
Endosymbiosis
Mitochondrion
Chloroplast
Photosynthetic eukaryotic cell
Photosynthetic prokaryote
Some cells
Figure 16.17

4. 16.18 Protists are an extremely diverse assortment of eukaryotes
Protist are mostly unicellular eukaryotes
Diplomonads
Euglenozoans
Dinoflagellates
Apicomplexans
Ciliates
Water molds
Diatoms
Brown algae
Amoebas
Plasmodial slime molds
Cellular slime molds
Fungi
Choanoflagellates
Animals
Red algae
Green algae
Closest algal relatives of plants
Plants
Alveolates
Stramenopila
Amoebozoa
Ancestral eukaryote
Figure 16.18

5. See other Protist notes for various groups of protists!
Characteristics
Examples

6. Life Cycle of Many Algae (Plant-like Protists)
The life cycles involve the alternation of haploid gametophyte and diploid sporophyte generations
Mitosis
Male gametophyte
Gametes
Spores
Meiosis
Fusion of gametes
Female gametophyte
Zygote
Sporophyte
Haploid (n)
Diploid (2n)
Key
Figure 16.24C

7. Probably by specialization of the cells of colonial protists
16.25 Multicellularity evolved several times in eukaryotes in several different lineages
Probably by specialization of the cells of colonial protists
Multicellular life arose over a billion years ago
Unicellular protist
Colony
Early multicellular organism with specialized, interdepen- dent cells
Later organism that produces gametes
Food- synthesizing cells
Locomotor cells
Somatic
cells
Gamete 1 2 3
Figure 16.25