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Basic Methods for the Study of Reproductive Ecology of Fish in Aquaria
Published on: July 20, 2017
Why are there so few fish in the sea?
Greta Carrete Vega1, John J Wiens
1Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA.
Proceedings. Biological Sciences
|February 10, 2012
Summary
Marine and freshwater fish diversity is surprisingly similar, challenging assumptions about ocean biodiversity. Ancient extinctions may explain why fewer species inhabit Earth
Area of Science:
- Comparative biodiversity
- Ichthyology
- Evolutionary biology
Background:
- A significant biodiversity gradient exists between marine and terrestrial environments, with terrestrial habitats hosting most species despite smaller surface areas.
- Marine environments, covering larger areas and volumes, paradoxically contain a smaller fraction of Earth's estimated biodiversity.
- Numerous hypotheses exist for this disparity, but large-scale quantitative tests are scarce.
Purpose of the Study:
- To quantitatively analyze patterns of diversity in actinopterygian (ray-finned) fishes, the most species-rich marine vertebrate clade.
- To investigate the reasons behind the paradoxically low diversity in marine environments compared to terrestrial ones.
- To test hypotheses explaining the marine-terrestrial biodiversity gradient using an entirely aquatic group.
Main Methods:
- Analysis of diversity patterns in actinopterygian fishes, encompassing both freshwater and marine habitats.
- Comparison of species richness and net diversification rates (speciation-extinction) between freshwater and saltwater clades.
- Trait reconstruction using both living and fossil taxa to infer evolutionary history.
Main Results:
- Actinopterygian fish richness is similar in freshwater (15,150 species) and marine (14,740 species) habitats, despite the larger area and productivity of marine environments.
- Net diversification rates are comparable between predominantly freshwater and saltwater clades.
- Trait reconstructions suggest all extant marine actinopterygians originated from a freshwater ancestor, implying ancient extinction played a role in current marine diversity.
Conclusions:
- The study challenges conventional understanding of marine biodiversity by revealing similar species richness in freshwater and marine actinopterygians.
- Ancient extinction events, rather than solely contemporary factors, may be crucial in explaining the lower diversity observed in marine ecosystems.
- Analyzing exclusively aquatic groups like ray-finned fishes provides a clearer perspective on the drivers of marine biodiversity patterns.
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