Đang chuẩn bị liên kết để tải về tài liệu:
Lecture Biology: Chapter 28 - Niel Campbell, Jane Reece

Chapter 28 introduce to protists. This chapter explain why the kingdom Protista is no longer considered a legitimate taxon; explain the process of endosymbiosis and state what living organisms are likely relatives of mitochondria and plastids; distinguish between endosymbiosis and secondary endosymbiosis; name the five supergroups, list their key characteristics, and describe some representative taxa. | Chapter 28 Protists Overview: Living Small Even a low-power microscope can reveal a great variety of organisms in a drop of pond water. Protist is the informal name of the kingdom of mostly unicellular eukaryotes, but there are some colonial and multicellular species. Protists constitute a paraphyletic group, and Protista is no longer valid as a kingdom. Protists exhibit more structural and functional diversity than any other group of eukaryotes. Protists can reproduce asexually or sexually, or by the sexual processes of meiosis and syngamy. Protists, the most nutritionally diverse of all eukaryotes, include: Photoautotrophs - contain chloroplasts. Heterotrophs - absorb organic molecules or ingest larger food particles. Mixotrophs - combine photosynthesis and heterotrophic nutrition. Endosymbiosis in Eukaryotic Evolution There is considerable evidence that much protist diversity has its origins in endosymbiosis. Mitochondria evolved by endosymbiosis of an aerobic prokaryote. Plastids evolved by endosymbiosis of a photosynthetic cyanobacterium. Endosymbiosis --> Eukaryotic Evolution Cyanobacterium Heterotrophic eukaryote Over the course of evolution, this membrane was lost. Red alga Green alga Primary endosymbiosis Secondary endosymbiosis Secondary endosymbiosis Secondary endosymbiosis Plastid Dinoflagellates Apicomplexans Stramenopiles Plastid Euglenids Chlorarachniophytes Figure 28.2 Diversity of plastids produced by secondary endosymbiosis Protist Diversity Green algae Amoebozoans Opisthokonts Alveolates Stramenopiles Diplomonads Parabasalids Euglenozoans Dinoflagellates Apicomplexans Ciliates Diatoms Golden algae Brown algae Oomycetes Excavata Chromalveolata Rhizaria Chlorarachniophytes Forams Radiolarians Archaeplastida Red algae Chlorophytes Charophyceans Land plants Unikonta Slime molds Gymnamoebas Entamoebas Nucleariids Fungi Choanoflagellates Animals Figure 28.3 Protist diversity For the Cell Biology Video Demonstration of Chemotaxis, go to Animation and . | Chapter 28 Protists Overview: Living Small Even a low-power microscope can reveal a great variety of organisms in a drop of pond water. Protist is the informal name of the kingdom of mostly unicellular eukaryotes, but there are some colonial and multicellular species. Protists constitute a paraphyletic group, and Protista is no longer valid as a kingdom. Protists exhibit more structural and functional diversity than any other group of eukaryotes. Protists can reproduce asexually or sexually, or by the sexual processes of meiosis and syngamy. Protists, the most nutritionally diverse of all eukaryotes, include: Photoautotrophs - contain chloroplasts. Heterotrophs - absorb organic molecules or ingest larger food particles. Mixotrophs - combine photosynthesis and heterotrophic nutrition. Endosymbiosis in Eukaryotic Evolution There is considerable evidence that much protist diversity has its origins in endosymbiosis. Mitochondria evolved by endosymbiosis of an aerobic prokaryote. Plastids