Many populations show a series of phenotypic variations as a result of environmental variations. These phenotypic variations usually remain even if the organisms are put in a different environment, and are inherited by their offspring, indicating that the characters are genetically rather than environmentally determined. Lets learn more about Ecotype and Ecads.
A Swedish ecologist Turesson (1925) studied a plant species which showed some genetically fixed phenotypic variations between populations of the Campanula rotundifolia. He found that mountain populations were shorter and flowered earlier than the lowland forms. This suited their growth in short mountain turf and their adaptation for rapid flowering and seed production in the shorter growing season in high altitude mountain habitats. Turesson called these phenotypically different forms ecotypes. An ecotype describes a genetically different population (subspecies) within a species which is adapted to specific environmental conditions. In ecotypes, adaptations become irreversible or genetically fixed. The different ecotypes of a particular species may differ in their edaphic, biotic or microclimatic requirements. Thus, ecotypes are genetically adapted local population. However, they are able to reproduce with other ecotypes of the same species and produce fertile offspring. Ecotypes can be classified and grouped together. A unit of classification which contains one or more ecotypes of a species is termed ecospecies. The term ecospecies has been proposed by Turesson. It is a unit of classification which contains one or more ecotypes, which although interfertile but do not cross or at least do not produce viable offsprings if crossed with ecotypes of other ecospecies. A species with a continuous distribution cannot be divided at any one point into two ecotypes. For this pattern of distribution, the term ecocline has been applied. Ecocline represents the continuous variation or gradual change in plant phenotype, and associated genotype along an environmental gradient.
An ecad (also known as ecophene) is a plant species is a population of individuals which although belong to the same genetic stock, but differ markedly in phenotypes such as size, shape and number of leaves, etc. These variations are environmentally induced, and thus are temporary or reversible, i.e. one type of ecad may change into another with a change in its habitat. So, if different ecads are transplanted in the same habitat, all would become similar in appearance. Thus, ecads show phenotypic plasticity i.e. environmentally induced phenotypic variation. The phenotypic plasticity is the capacity of a single genotype to exhibit variable phenotypes in different environments. It is considered one of the major means by which plants can cope with environmental factor variability.
FAQs on Ecotype and Ecads
An ecotype is a type of variation where the differences in appearance are too few or too small to be called a subspecies.
Ecads or morphologically altered forms. When a species is moved to a new habitat, its initial response is to acquire survival skills. For example, when a European visits the tropics, his skin darkens as a result of increased melanin production.