coral reefs in Indonesia. Indonesian Journal of Marine and
Coastal Resources, 4, 1–19.
Wallace, C. C, Chen, C. A. C., Fukami, H., and Muir, P. R., 2007.
Recognition of separate genera within Acropora based on
new morphological, reproductive and genetic evidence from
A. togianensis, and elevation of the subgenus Isopora Studer,
1878 to genus (Scleractinia: Astrocoeniidae; Acroporidae).
Coral Reefs, 26, 231–239.
Wells, J. W., 1956. Scleractinia. In Moore, R. C. (ed.), Treatise on
Invertebrate Paleontology, Part F (Coelenterata), Lawrence:
The University of Kansas Press, pp. F328–F444.
Wilkinson, C. R. (ed.), (1998, 2000, 2002, 2004, 2008) Status of the
Coral Reefs of the World. Townsville: Australian Institute of
Marine Science.
Williams, E. H., Jr., Bartels, P. J., and Bunkley-Williams, L., 1999.
Predicted disappearance of coral-reef ramparts: a direct result of
major ecological disturbances. Global Change Biology, 5, 839–845.
Wolstenholme, J. K., Wallace, C. C., and Chen, C., 2003. Species
boundaries within the Acropora humilis species group (Cnidaria;
Scleractinia): a morphological and molecular interpretation of
evolution. Coral Reefs, 22, 155–166.
Cross-references
Carbonate Budgets and Reef Framework Accumulation
Corals: Biology, Skeletal Deposition, and Reef-Building
General Evolution of Carbonate Reefs
Porites
Scleractinia, Evolution and Taxonomy
ADAPTATION
David Obura
CORDIO East Africa, Mombasa, Kenya
Definition
Adaptation is the process of change in the structure or
function of an organism or parts of an organism that makes
it better suited to the environment in which it lives. Adaptations (or traits that are adaptive) that are heritable, i.e.,
coded in genes or that have consequences on the reproductive success of genes, contribute to natural selection.
Acclimatization refers to adjustment to local conditions that occurs within the lifetime of an individual, in
response to external environmental conditions, for example, through behavioral changes, or increased tolerance
of stressful conditions. Acclimation is similar, though is
applied more narrowly to artificial conditions and experimentation. Both can lead to true adaptation if and when
the relevant traits are passed on to the next generations.
Introduction
Adaptation is a core concept of evolutionary biology, its
significance recognized by Charles Darwin (Darwin,
Charles (1809–1882)) as a central tenet of his theory of
evolution by natural selection (Darwin, 1856). Simply
stated, differences in individuals of a species, or among
species, may confer differential survival or performance,
and thus influence which individuals survive and
reproduce, and thereby the passing of favorable traits on
to offspring. Where traits shift or adjust to suit local conditions, beneficial ones can be viewed as “adaptations,” and
may confer evolutionary success.
Adaptation is a whole-organism phenomenon. Change in
a trait that confers benefits in one area but imposes costs or
dysfunction in another may not lead to adaptation if the costs
outweigh the benefits. Thus tradeoffs between traits are an
essential part of the process of adaptation, placing constraints on what changes are beneficial. This is recognized
in life history theory, which relates how organisms divide
limited energy and resources to different functions and processes, how the balance between these may change with
external conditions, and how these changes result in differential success among life history strategies (Stearns, 1992).
Adaptation is such a wide-ranging process that generalizations about it are often not true in all conditions.
For example, severe environmental conditions may pose
strong selective pressures leading to rapid adaptation to
environmental stress in that part of the population that survives (Hoffman and Parsons, 1991). In this case, adaptation
occurs by extermination of “unfit” genes under rapid environmental change. On the other hand, benign conditions
enable beneficial traits to accumulate in a population over
successive generations. In this case, adaptation occurs by
competitive success of beneficial genes over less-fit genes.
Not all traits that occur in an organism are certain to be
adaptive; they may simply not have a negative impact on
the individual’s or species’ survival. Thus, it is necessary
to determine specifically if a trait is adaptive through careful
observation or experimentation, rather than by simply
observing its presence (Gould and Lewontin, 1994). The
evolution and taxonomy (Coral Cay Classification and
Evolution) of extant reef corals provides key insights into
the unusual evolutionary pressures faced by corals and
hence of their capacity for adaptation.
Coral reefs are typically considered to occur in relatively
benign and stable environmental conditions (Corals:
Environmental Controls on Growth), with high density
and diversity of organisms. This creates conditions for high
levels of niche diversification and diversification of interactions, and for these to become stable over time. Thus adaption, or coadaptation (among mutually interacting species),
is common on reefs and can be distinguished in many forms
of interactions, such as:
1. Primary production: Different functional groups of primary producers, characterized by whether they form hard
crusts that resist herbivory and cement reefs, fast-growing
low-biomass algal filaments and turfs with high recovery
rates from removal, and large-bodied fleshy algal fronds
that resist herbivory through low palatability and compete
with other sessile organisms to monopolize space (Algae,
Coralline; Algae-Macro; Algae, Turf );
2. Predator–prey dynamics: A vast array of different prey
and predators, and of defense and predation mechanisms. Adaptations of fish consumers are clear in their
jaw structures toward their prey (Figure 1): scraping
ADAPTATION
9
Coastal Resources, 4, 1–19.
Wallace, C. C, Chen, C. A. C., Fukami, H., and Muir, P. R., 2007.
Recognition of separate genera within Acropora based on
new morphological, reproductive and genetic evidence from
A. togianensis, and elevation of the subgenus Isopora Studer,
1878 to genus (Scleractinia: Astrocoeniidae; Acroporidae).
Coral Reefs, 26, 231–239.
Wells, J. W., 1956. Scleractinia. In Moore, R. C. (ed.), Treatise on
Invertebrate Paleontology, Part F (Coelenterata), Lawrence:
The University of Kansas Press, pp. F328–F444.
Wilkinson, C. R. (ed.), (1998, 2000, 2002, 2004, 2008) Status of the
Coral Reefs of the World. Townsville: Australian Institute of
Marine Science.
Williams, E. H., Jr., Bartels, P. J., and Bunkley-Williams, L., 1999.
Predicted disappearance of coral-reef ramparts: a direct result of
major ecological disturbances. Global Change Biology, 5, 839–845.
Wolstenholme, J. K., Wallace, C. C., and Chen, C., 2003. Species
boundaries within the Acropora humilis species group (Cnidaria;
Scleractinia): a morphological and molecular interpretation of
evolution. Coral Reefs, 22, 155–166.
Cross-references
Carbonate Budgets and Reef Framework Accumulation
Corals: Biology, Skeletal Deposition, and Reef-Building
General Evolution of Carbonate Reefs
Porites
Scleractinia, Evolution and Taxonomy
ADAPTATION
David Obura
CORDIO East Africa, Mombasa, Kenya
Definition
Adaptation is the process of change in the structure or
function of an organism or parts of an organism that makes
it better suited to the environment in which it lives. Adaptations (or traits that are adaptive) that are heritable, i.e.,
coded in genes or that have consequences on the reproductive success of genes, contribute to natural selection.
Acclimatization refers to adjustment to local conditions that occurs within the lifetime of an individual, in
response to external environmental conditions, for example, through behavioral changes, or increased tolerance
of stressful conditions. Acclimation is similar, though is
applied more narrowly to artificial conditions and experimentation. Both can lead to true adaptation if and when
the relevant traits are passed on to the next generations.
Introduction
Adaptation is a core concept of evolutionary biology, its
significance recognized by Charles Darwin (Darwin,
Charles (1809–1882)) as a central tenet of his theory of
evolution by natural selection (Darwin, 1856). Simply
stated, differences in individuals of a species, or among
species, may confer differential survival or performance,
and thus influence which individuals survive and
reproduce, and thereby the passing of favorable traits on
to offspring. Where traits shift or adjust to suit local conditions, beneficial ones can be viewed as “adaptations,” and
may confer evolutionary success.
Adaptation is a whole-organism phenomenon. Change in
a trait that confers benefits in one area but imposes costs or
dysfunction in another may not lead to adaptation if the costs
outweigh the benefits. Thus tradeoffs between traits are an
essential part of the process of adaptation, placing constraints on what changes are beneficial. This is recognized
in life history theory, which relates how organisms divide
limited energy and resources to different functions and processes, how the balance between these may change with
external conditions, and how these changes result in differential success among life history strategies (Stearns, 1992).
Adaptation is such a wide-ranging process that generalizations about it are often not true in all conditions.
For example, severe environmental conditions may pose
strong selective pressures leading to rapid adaptation to
environmental stress in that part of the population that survives (Hoffman and Parsons, 1991). In this case, adaptation
occurs by extermination of “unfit” genes under rapid environmental change. On the other hand, benign conditions
enable beneficial traits to accumulate in a population over
successive generations. In this case, adaptation occurs by
competitive success of beneficial genes over less-fit genes.
Not all traits that occur in an organism are certain to be
adaptive; they may simply not have a negative impact on
the individual’s or species’ survival. Thus, it is necessary
to determine specifically if a trait is adaptive through careful
observation or experimentation, rather than by simply
observing its presence (Gould and Lewontin, 1994). The
evolution and taxonomy (Coral Cay Classification and
Evolution) of extant reef corals provides key insights into
the unusual evolutionary pressures faced by corals and
hence of their capacity for adaptation.
Coral reefs are typically considered to occur in relatively
benign and stable environmental conditions (Corals:
Environmental Controls on Growth), with high density
and diversity of organisms. This creates conditions for high
levels of niche diversification and diversification of interactions, and for these to become stable over time. Thus adaption, or coadaptation (among mutually interacting species),
is common on reefs and can be distinguished in many forms
of interactions, such as:
1. Primary production: Different functional groups of primary producers, characterized by whether they form hard
crusts that resist herbivory and cement reefs, fast-growing
low-biomass algal filaments and turfs with high recovery
rates from removal, and large-bodied fleshy algal fronds
that resist herbivory through low palatability and compete
with other sessile organisms to monopolize space (Algae,
Coralline; Algae-Macro; Algae, Turf );
2. Predator–prey dynamics: A vast array of different prey
and predators, and of defense and predation mechanisms. Adaptations of fish consumers are clear in their
jaw structures toward their prey (Figure 1): scraping
ADAPTATION
9