The adaptive role of melanin plasticity in thermally variable environments (2024)

FAQs

What is melanin plasticity? ›

Plasticity in melanin pigmentation is common in response to variable environments, especially thermal environments. Yet, the adaptive significance of melanin plasticity in thermally variable environments is often assumed, but rarely explicitly tested.

Adaptive phenotypic plasticity is the ability of a genotype to express phenotypes for improved ecological performance when exposed to different local environments (Robinson and Parsons 2002; Dewitt and Scheiner 2004; Ghalambor et al. 2007).

Many organisms have the ability to express different phenotypes in response to environmental conditions. Such phenotypic plasticity allows individual organisms to develop appropriate morphological, physiological, or behavioral traits that better fit a particular environment that they encounter.

In changing environments, phenotypic plasticity allows organisms to conserve their genotypes and still produce alternative phenotypes [1,2,3,4], in contrast to local adaptations that incorporate changes at the genetic level producing long-lasting phenotypes and resulting in higher fitness in home habitats [5,6].

Plasticity enables a solid under the action of external forces to undergo permanent deformation without rupture. Elasticity, in comparison, enables a solid to return to its original shape after the load is removed.

Melanin takes in excessive light energy and converts it to heat in a process called absorption; heat is then dissipated into the environment as infrared radiation, thereby protecting the underlying skin.

Phenotypic plasticity refers to the ability of a genotype to express different phenotypes depending on the environment in which it resides. For example, genetically identical water flea (Daphnia) clones can differ in their morphology depending on whether reared in the absence or presence of a potential predator.

Phenotypic plasticity is a major mechanism of response to environmental variability, which may allow organisms to cope with rapid environmental changes, including global change.

Plasticity is what makes the appearance of an environmentally induced novel phenotype possible, and a process of selection on the expression of such phenotype in a new environment may end up “fixing” (genetically assimilating) it by altering the shape of the reaction norm [75].

Phenotypic plasticity encompasses a wide range of adaptive and non-adaptive responses to heterogeneous environments, yet too often the term plasticity is used in a general context that obscures different kinds of environmentally induced variation, with different consequences for the likelihood of persistence and ...

Does phenotypic plasticity prevent rapid adaptation? ›

In these ways, phenotypic plasticity has underpinned rapid divergent adaptation in female fecundity, which is finely tuned to local environmental variation. Understanding the scale and pace of local adaptation is a long‐standing problem in evolutionary biology.

Plasticity is evolutionarily favored when the environment is heterogeneous in time or space, selection favors different phenotypes in different environments, no one phenotype has greatest fitness across all environments, and reliable cues allow organisms to respond effectively (Bradshaw 1965; Via & Lande 1985; ...

Currently, no safe or proven method exists to increase melanin – the pigment, or color, in a person's skin, hair, and eyes. A person's genetics determine their natural melanin levels and skin color. In general, people who have darker skin tones have more melanin than those with lighter skin tones.

Developmental plasticity, defined as 'the ability of an organism to react to an internal or external environmental input with a change in form, state, movement, or rate of activity,' is broad enough to include most of animal behavior (see West-Eberhard's (2003) book for a more detailed discussion of this definition).

Microscopic appearance. Melanin is brown, non-refractile, and finely granular with individual granules having a diameter of less than 800 nanometers. This differentiates melanin from common blood breakdown pigments, which are larger, chunky, and refractile, and range in color from green to yellow or red-brown.

The life cycle of melanocytes consists of several steps including lineage specification from embryonic neural crest cells (melanoblasts), migration and proliferation of melanoblasts, differentiation of melanoblasts into melanocytes, maturation of melanocytes (melanin production in special organelles – melanosomes, ...