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Morphologically Conservative but Physiologically Diverse: The Mode of Stasis in Anostraca (Crustacea: Branchiopoda).

Lindholm M - Evol Biol (2014)

Bottom Line: Examples from the class Branchiopoda show that morphological conservatism is associated with enemy free space in species-poor habitats dominated by abiotic factors, while Red Queen mechanisms are predominant in larger systems with complex biotic interactions.Splitting of Branchiopod main lineages is associated with increased fish predation during the Devonian.Hence, although morphologically conservative and possessing traits typical for "living fossils", anostracan physiological abilities are closely adapted to the challenging and variable physicochemical conditions of ponds and ephemeral pools.

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Affiliation: Norwegian Institute for Water Research/NIVA, Gaustadalleen 23, 0349 Oslo, Norway.

ABSTRACT
The essay discusses whether biotic and abiotic environments differ in their ability to speed up or slow down morphological change and the generation of new lineages. Examples from the class Branchiopoda show that morphological conservatism is associated with enemy free space in species-poor habitats dominated by abiotic factors, while Red Queen mechanisms are predominant in larger systems with complex biotic interactions. Splitting of Branchiopod main lineages is associated with increased fish predation during the Devonian. The order Cladocera adapted and remained in larger aquatic systems, and subsequently generated a variety of new families, genera and species. The order Anostraca, on the other hand, maintained its ancestral morphology and survived only as "living fossils" in isolated ponds of harsh habitats. Despite their archaic morphology, however, they possess highly sophisticated adaptations to local physicochemical properties of their extreme environment. Hence, although morphologically conservative and possessing traits typical for "living fossils", anostracan physiological abilities are closely adapted to the challenging and variable physicochemical conditions of ponds and ephemeral pools.

No MeSH data available.


Related in: MedlinePlus

The fairy shrimp Branchinecta paludosa (drawing by G.O. Sars)
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Fig2: The fairy shrimp Branchinecta paludosa (drawing by G.O. Sars)

Mentions: Anostracans responded different. Despite considerable size, they retained their archaic morphology. They still move slowly upside down through the open pelagial, filtering particles from the water, unable to hide in the bottom substrate, and hence an easy prey for fish (Fig. 2). The extreme rarity of coexistence between fairy shrimps and fish is consistent with this pattern, as are the detrimental effects of fish stocking on fairy shrimp populations (Eriksen and Belk 1999; Lindholm et al. 2012). Anostracan only survived in small, isolated habitats with peculiar features, and devoid of fish: shallow ponds and ephemeral pools, predominantly in inhospitable and extreme environments.Fig. 2


Morphologically Conservative but Physiologically Diverse: The Mode of Stasis in Anostraca (Crustacea: Branchiopoda).

Lindholm M - Evol Biol (2014)

The fairy shrimp Branchinecta paludosa (drawing by G.O. Sars)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4129224&req=5

Fig2: The fairy shrimp Branchinecta paludosa (drawing by G.O. Sars)
Mentions: Anostracans responded different. Despite considerable size, they retained their archaic morphology. They still move slowly upside down through the open pelagial, filtering particles from the water, unable to hide in the bottom substrate, and hence an easy prey for fish (Fig. 2). The extreme rarity of coexistence between fairy shrimps and fish is consistent with this pattern, as are the detrimental effects of fish stocking on fairy shrimp populations (Eriksen and Belk 1999; Lindholm et al. 2012). Anostracan only survived in small, isolated habitats with peculiar features, and devoid of fish: shallow ponds and ephemeral pools, predominantly in inhospitable and extreme environments.Fig. 2

Bottom Line: Examples from the class Branchiopoda show that morphological conservatism is associated with enemy free space in species-poor habitats dominated by abiotic factors, while Red Queen mechanisms are predominant in larger systems with complex biotic interactions.Splitting of Branchiopod main lineages is associated with increased fish predation during the Devonian.Hence, although morphologically conservative and possessing traits typical for "living fossils", anostracan physiological abilities are closely adapted to the challenging and variable physicochemical conditions of ponds and ephemeral pools.

View Article: PubMed Central - PubMed

Affiliation: Norwegian Institute for Water Research/NIVA, Gaustadalleen 23, 0349 Oslo, Norway.

ABSTRACT
The essay discusses whether biotic and abiotic environments differ in their ability to speed up or slow down morphological change and the generation of new lineages. Examples from the class Branchiopoda show that morphological conservatism is associated with enemy free space in species-poor habitats dominated by abiotic factors, while Red Queen mechanisms are predominant in larger systems with complex biotic interactions. Splitting of Branchiopod main lineages is associated with increased fish predation during the Devonian. The order Cladocera adapted and remained in larger aquatic systems, and subsequently generated a variety of new families, genera and species. The order Anostraca, on the other hand, maintained its ancestral morphology and survived only as "living fossils" in isolated ponds of harsh habitats. Despite their archaic morphology, however, they possess highly sophisticated adaptations to local physicochemical properties of their extreme environment. Hence, although morphologically conservative and possessing traits typical for "living fossils", anostracan physiological abilities are closely adapted to the challenging and variable physicochemical conditions of ponds and ephemeral pools.

No MeSH data available.


Related in: MedlinePlus