8 Morphology and Ecological Physiology
of Corals
Many important properties of coral reef ecosystems are closely connected
with the morphological and functional characteristics of the corals
themselves, as dominant inhabitants of their bottom biotopes. Among these
properties there could be mentioned the adaptive variability of corals, their
endosymbiosis with algae, and their ability for autotrophic feeding coupled
with heterotrophy. Below the most important points of the ecological
morphology and physiology of corals are discussed. The anatomy of polyps
and the morphology of corallites and of coral colonies have been described
in corresponding reviews, and we will deal with them only in part if
necessary. Among these reviews should be mentioned: Hyman (1940),
Bayer (1973), Coates and Oliver (1973), Mariscal (1974), Preobrazhenski
(1986), and Sokolov (1987).
8.1 Features of Ecological Morphology
Colonies of corals are constructed from separate modules, corallites,
connected within a united structure. They are formed by sister polyps,
multiplying by budding, and thus represent the clone of genetically identical
animals. By the vegetative propagation (cf. Sect. 7.4) the coral colony is
able to produce other identical clones. Therefore, in the natural populations
of corals clones of polyps exist, which are represented by different colonies.
Being a separate monoclonal multimodular but unique organism, the coral
colony itself thus became an object of natural selection (Wells 1971). This
resulted in the appearance of a multitude of species of modern corals within
a relatively short geological time. The statement that the coral colony "is the
animal with many mouths", has been offered by Sir Maurice Yonge long
ago (Yonge 1930a). To it should be added another one - it is also something
like "the plant with many leaves". In fact, the colonies of scleractinian
corals, and even most of the octocorals, possess the structures that provide
the interconnection between the polyps and so unite them into a single
organism. In colonies of scleractinians gastrovascular channels were found
through which the exchange with nutritional substances takes place
of Corals
Many important properties of coral reef ecosystems are closely connected
with the morphological and functional characteristics of the corals
themselves, as dominant inhabitants of their bottom biotopes. Among these
properties there could be mentioned the adaptive variability of corals, their
endosymbiosis with algae, and their ability for autotrophic feeding coupled
with heterotrophy. Below the most important points of the ecological
morphology and physiology of corals are discussed. The anatomy of polyps
and the morphology of corallites and of coral colonies have been described
in corresponding reviews, and we will deal with them only in part if
necessary. Among these reviews should be mentioned: Hyman (1940),
Bayer (1973), Coates and Oliver (1973), Mariscal (1974), Preobrazhenski
(1986), and Sokolov (1987).
8.1 Features of Ecological Morphology
Colonies of corals are constructed from separate modules, corallites,
connected within a united structure. They are formed by sister polyps,
multiplying by budding, and thus represent the clone of genetically identical
animals. By the vegetative propagation (cf. Sect. 7.4) the coral colony is
able to produce other identical clones. Therefore, in the natural populations
of corals clones of polyps exist, which are represented by different colonies.
Being a separate monoclonal multimodular but unique organism, the coral
colony itself thus became an object of natural selection (Wells 1971). This
resulted in the appearance of a multitude of species of modern corals within
a relatively short geological time. The statement that the coral colony "is the
animal with many mouths", has been offered by Sir Maurice Yonge long
ago (Yonge 1930a). To it should be added another one - it is also something
like "the plant with many leaves". In fact, the colonies of scleractinian
corals, and even most of the octocorals, possess the structures that provide
the interconnection between the polyps and so unite them into a single
organism. In colonies of scleractinians gastrovascular channels were found
through which the exchange with nutritional substances takes place