Vavilovian mimicry

Vavilovian mimicry describes weeds which come to share characteristics with a domesticated plant through artificial selection.[7] It is named after Russian botanist and geneticist Nikolai Vavilov.[38] Selection against the weed may occur either by manually killing the weed, or by separating its seeds from those of the crop. The latter process, known as winnowing, can be done manually or by a machine. Vavilovian mimicry presents an illustration of unintentional (or rather 'anti-intentional') selection by man. While some cases of artificial selection go in the direction desired, such as selective breeding, this case presents the opposite characteristics. Weeders do not want to select weeds that look increasingly like the cultivated plant, yet there is no other option. A similar problem in agriculture is pesticide resistance: farmers do not wish to select for weeds that have increasingly similar resistance to pesticides as the crop itself, yet that is the inevitable effect. Vavilovian mimics may eventually be domesticated themselves, and Vavilov called these weed-crops secondary crops. It can be classified as defensive mimicry in that the weed mimics a protected species. This bears strong similarity to Batesian mimicry in that the weed does not share the properties that give the model its protection, and both the model and the dupe (in this case people) are harmed by its presence. There are some key differences, though; in Batesian mimicry the model and signal receiver are enemies (the predator would eat the protected species if it could), whereas here the crop and its human growers are in a mutualistic relationship: the crop benefits from being dispersed and protected by people, despite being eaten by them. In fact, the crop's only 'protection' relevant here is its usefulness to humans. Secondly, the weed is not eaten, but simply destroyed. The only motivation for killing the weed is its effect on crop yie

ds. Finally, this type of mimicry does not occur in ecosystems unaltered by humans. One case is Echinochloa oryzoides, a species of grass which is found as a weed in rice (Oryza sativa) fields. The plant looks similar to rice and its seeds are often mixed in rice and difficult to separate. This close similarity was enhanced by the weeding process which is a selective force that increases the similarity of the weed in each subsequent generation. A crop is a volunteered or cultivated plant (any plant) whose produce is harvested by man at some point of its growth stage. plants which have not been cultivated but whose produce are harvested, are not really classified as crops the same goes for plants which have been planted are are never harvested. flowers are classified as crops because when it has been cultivated, its harvesting also include the aesthetic purpose it serves. Crops refer to plants that are grown on a large scale for food, clothing, and other human uses. They are non-animal species or varieties grown to be harvested as food, livestock fodder, fuel or for any other economic purpose (for example, for use as dyes, medicinal, and cosmetic use). Major crops include sugarcane, pumpkin, maize (corn), wheat, rice, cassava, soybeans, hay, potatoes and cotton.[1] While the term "crop" most commonly refers to plants, it can also include species from other biological kingdoms. For example, mushrooms like shiitake, which are in the fungi kingdom, can be referred to as "crops". In addition, certain species of algae are also cultivated, although it is also harvested from the wild. In contrast, animal species that are raised by humans are called livestock, except those that are kept as pets. Microbial species, such as bacteria or viruses, are referred to as cultures. Microbes are not typically grown for food, but are rather used to alter food. For example, bacteria are used to ferment milk to produce yogurt.