BIOL 1209 Chapter : 20140422 161025
Chapter 28- Protists
Concept 28.1- Most eukaryotes are single celled organisms
o Protists are more diverse than all other eukaryotes
▪ No longer considered a single kingdom
o Mostly unicellular, but some colonial and multicellular forms
• Protists are nutritionally diverse
o Photoautotrophs
▪ Contain chloroplasts, photosynthesize
o Heterotrophs
▪ Absorb organic molecules or ingest larger particles
o Mixotrophs
▪ Combine photosynthesis and hertotrophic nutrition
• Endosymbiosis in eukaryotic evolution
o Much protest diversity has its origin in endosymbiosis
o Plastid-bearing lineage evolved into red and green algae
o Both underwater secondary endosymbiosis
• Motility in protists
o Flagellates- move by one or more flagellae
o Ciliates- move by coordinated movement of cilia
o Amoebae- move by means of pseudopodia (extension of membrane)
o Figure 28.7
• Sexual reproduction in protists
o Protists have a wide variety of histories
▪ Zygotic life cycle- haploid cells transform into gametes, gametes fuse into
zygotes (plasmodium, causes malaria)
▪ Alternation of generations- produce types of multicellular organisms
(n and 2n), many algae and all land plants
• Ciliate sexual reproduction
• Protest diversity
o Protistans are a paraphyletic group
▪ 5 super groups
• Excarata
• Chromalveolata
• Rhizaria
• Archaeplastida
• Unikonta
