Sheep farmingSheep farming or sheep husbandry is the raising and breeding of domestic sheep. It is a branch of animal husbandry. Sheep are raised principally for their meat (lamb and mutton), milk (sheep's milk), and fiber (wool). They also yield sheepskin and parchment. Sheep can be raised in a range of temperate climates, including arid zones near the equator and other torrid zones. Farmers build fences, housing, shearing sheds, and other facilities on their property, such as for water, feed, transport, and pest control.
Draft horseA draft horse (US), draught horse (UK) or dray horse (from the Old English dragan meaning "to draw or haul"; compare Dutch dragen and German tragen meaning "to carry" and Danish drage meaning "to draw" or "to fare"), less often called a carthorse, work horse or heavy horse, is a large horse bred to be a working animal doing hard tasks such as plowing and other farm labor. There are a number of breeds, with varying characteristics, but all share common traits of strength, patience, and a docile temperament which made them indispensable to generations of pre-industrial farmers.
Genetic diversityGenetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment.
Directional selectionIn population genetics, directional selection, is a mode of negative natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype. Under directional selection, the advantageous allele increases as a consequence of differences in survival and reproduction among different phenotypes. The increases are independent of the dominance of the allele, and even if the allele is recessive, it will eventually become fixed.
Stabilizing selectionStabilizing selection (not to be confused with negative or purifying selection) is a type of natural selection in which the population mean stabilizes on a particular non-extreme trait value. This is thought to be the most common mechanism of action for natural selection because most traits do not appear to change drastically over time. Stabilizing selection commonly uses negative selection (a.k.a. purifying selection) to select against extreme values of the character. Stabilizing selection is the opposite of disruptive selection.
Domestication of the horseHow and when horses became domesticated has been disputed. Although horses appeared in Paleolithic cave art as early as 30,000 BCE, these were wild horses and were probably hunted for meat. The clearest evidence of early use of the horse as a means of transport is from chariot burials dated c. 2000 BCE. However, an increasing amount of evidence began to support the hypothesis that horses were domesticated in the Eurasian Steppes in approximately 3500 BCE.
Water buffaloThe water buffalo (Bubalus bubalis), also called the domestic water buffalo or Asian water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also found in Italy, the Balkans, Australia, North America, South America and some African countries. Two extant types of water buffalo are recognized, based on morphological and behavioural criteria: the river buffalo of the Indian subcontinent and further west to the Balkans, Egypt and Italy and the swamp buffalo, found from Assam in the west through Southeast Asia to the Yangtze valley of China in the east.
YakThe domestic yak (Bos grunniens), also known as the Tartary ox, grunting ox, or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Gilgit-Baltistan (Kashmir), Tajikistan and as far north as Mongolia and Siberia. It is descended from the wild yak (Bos mutus). The English word yak originates from the . In Tibetan and Balti it refers only to the male of the species, the female being called , or in Tibetan and in Balti.
Molecular geneticsMolecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the structure and/or function of genes in an organism's genome using genetic screens. The field of study is based on the merging of several sub-fields in biology: classical Mendelian inheritance, cellular biology, molecular biology, biochemistry, and biotechnology.
Horses in the Middle AgesHorses in the Middle Ages differed in size, build and breed from the modern horse, and were, on average, smaller. They were also more central to society than their modern counterparts, being essential for war, agriculture, and transport. Consequently, specific types of horse developed, many of which have no modern equivalent. While an understanding of modern horse breeds and equestrianism is vital for any analysis of the medieval horse, researchers also need to consider documentary (both written and pictorial) and archaeological evidence.
