Book contents
- Evolutionary Physiology of Algae and Aquatic Plants
- Evolutionary Physiology of Algae and Aquatic Plants
- Copyright page
- Contents
- Contributors
- Preface
- Acknowledgments
- 1 Environmental Changes Impacting on, and Caused by, the Evolution of Photosynthetic Organisms
- Part I Origins and Consequences of Early Photosynthetic Organisms
- 2 Early Photosynthetic Organisms
- 3 …And Nothing Was the Same Anymore: The Rise in O2 and Consequences for Photoautotrophs
- 4 The Appearance of Eukaryotic Microalgae
- 5 The Appearance of Macroalgae: Evolution and Ecological Consequences of Multicellularity
- 6 The Evolution of Aquatic Embryophytes: Secondary Colonisers of Aquatic Environments
- Part II Physiology of Photosynthetic Autotrophs in Present-Day Environments
- Part III The Future
- Index
- References
4 - The Appearance of Eukaryotic Microalgae
from Part I - Origins and Consequences of Early Photosynthetic Organisms
Published online by Cambridge University Press: 24 October 2024
- Evolutionary Physiology of Algae and Aquatic Plants
- Evolutionary Physiology of Algae and Aquatic Plants
- Copyright page
- Contents
- Contributors
- Preface
- Acknowledgments
- 1 Environmental Changes Impacting on, and Caused by, the Evolution of Photosynthetic Organisms
- Part I Origins and Consequences of Early Photosynthetic Organisms
- 2 Early Photosynthetic Organisms
- 3 …And Nothing Was the Same Anymore: The Rise in O2 and Consequences for Photoautotrophs
- 4 The Appearance of Eukaryotic Microalgae
- 5 The Appearance of Macroalgae: Evolution and Ecological Consequences of Multicellularity
- 6 The Evolution of Aquatic Embryophytes: Secondary Colonisers of Aquatic Environments
- Part II Physiology of Photosynthetic Autotrophs in Present-Day Environments
- Part III The Future
- Index
- References
Summary
Microalgae, with cyanobacteria, are the major primary producers in aquatic, predominantly marine, ecosystems, contributing to the biogeochemical cycling of multiple elements despite their small instantaneous biomass. Their evolutionary history revealed by genomic analyses has shown a complex past that produces a polyphyletic group including organisms that have undergone primary, secondary and tertiary chloroplast endosymbiosis with genetic integration and also horizontal gene transfer. All but one genus of photosynthetic eukaryotes arose by endosymbiosis of a gloeomargarita-like β-cyanobacterium in a eukaryote with the retention of some genes in the plastid, the transfer of more genes to the eukaryote nucleus, and the loss of many others, to produce the Archaeplastida. A second, much later, endosymbiosis of an α-cyanobacterium in a euglyphid amoeba yielded Paulinella. The diversification of the Archaeplastida yielded Glaucophyta, Rhodophyta, Chlorophyta and Streptophyta. Secondary endosymbiosis of red algae in eukaryotes led to microalgae of the ‘red line’, that is, photosynthetic Ochrista (= stramenopiles), Haptophyta, Cryptophyta and Alveolata (dinoflagellates and chromerids). Secondary endosymbiosis of chlorophyte algae in eukaryotes yielded microalgae of the Chlorarachniophyta and Euglenophyta. The ‘red line’ of secondary endosymbionts are dominant marine phytoplankton, possibly related to the occurrence of chlorophyll c that has high absorbance of blue light that dominates in deep ocean waters.
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- Evolutionary Physiology of Algae and Aquatic Plants , pp. 65 - 79Publisher: Cambridge University PressPrint publication year: 2024