Hair color is passed down by parents only. Natural hair color can be given only by genes. It is impossible to have a hair color that is not passed down genetically by both mother and father. This relies on dominant and recessive genes carried by a parent. These genes may not be the color of their hair, however, many people carry genes that are recessive and do not show in their traits or features.
Dyeing hair is to change the color of hair. It consists of a chemical mixture which can change the color of hair by a chemical reaction. Many people dye their hair to hide gray or white hairs. This is because most people gain white or gray hairs as they grow older.
Two types of melanin pigment give hair its color: "eumelanin" and "pheomelanin". Pheomelanin colors hair red. Eumelanin determines the darkness of the hair color. A low concentration of brown eumelanin results in blond hair, but more brown eumelanin will color the hair brown. High amounts of black eumelanin result in black hair, while low concentrations give gray hair. All humans have some pheomelanin in their hair.
The genetics of hair colors are not yet firmly established. According to one theory, at least two gene pairs control human hair color.
One phenotype (brown/blond) has a dominant brown allele and a recessive blond allele. A person with a brown allele will have brown hair; a person with no brown alleles will be blond. This explains why two brown-haired parents can produce a blond-haired child.
The other gene pair is a non-red/red pair, where the not-red allele is dominant and the allele for red hair is recessive. A person with two copies of the red-haired allele will have red hair, but it will be either auburn or bright reddish orange depending on whether the first gene pair gives brown or blond hair, respectively.
The two-gene model does not account for all possible shades of brown, blond, or red (for example, platinum blond versus dark blonde/light brown), nor does it explain why hair color sometimes darkens as a person ages. Several other gene pairs control the light versus dark hair color in a cumulative effect (quantitative genetics).
Hair texture is also inherited genetically. The thickness of hair, its color and its tendency to curl are all inherited. There are also genetic differences between men and women. Body hair is limited in women, and thicker in men.
People have about 100,000 hairs on their head. About 100 fall out each day, but they usually grow back. Some men are bald but girls and women may become bald if they lose their hair from a disease called alopecia.
Men often lose some of their hair as they grow older. This is known as "baldness". Doctors call it "male pattern baldness" because hairs often fall out in similar places. It often begins by hair falling out first from the front of the head, and then from the top of the head. After a while, all that may be left is a some hair running above the ears and around the lower back of the head. Even though it is unusual for women to go bald, many women suffer from thinning hair over the top of their head as they grow old.
People have tried to find cures for hair loss for thousands of years. In an effort to get their hair back, men have tried "cures" like applying strange lotions or even having their heads packed in chicken manure. Many unproven "cures" are still marketed today. It is only in the last decade or so that treatments have been developed which do sometimes work. Some doctors do hair transplants, where they take tiny plugs of hair from areas like the back of the neck and plant them in the bald spots on the head. Some drugs have been tested and approved for sale as hair loss treatments. They encourage hair regrowth and thickening, but work better if applied before hair loss turns to baldness.
People have been interested in hair on their heads for hundreds of thousands of years. For both men and women, styling and coloring hair have been ways to look good, and get attention. Sometimes society makes rules about hair, for example by not allowing people to cut their hair or beards, like in Sikhism (it is also good to do this in Islam, but not a requirement).
Ireland
Ireland (; ; Ulster-Scots: ) is an island in the North Atlantic. It is about 486 kilometres (302 miles) long and about 288 kilometres (179 miles) wide. To the west of Ireland is the Atlantic Ocean; to the east of Ireland, across the Irish Sea, is the island of Great Britain. Over 6.4 million people lived on the island in 2016.
Today, the island of Ireland is made up of two countries: the Republic of Ireland and Northern Ireland:
From 1801 to 1921, all of Ireland was part of the same country, called the United Kingdom of Great Britain and Ireland. In 1919, a war broke out, the Irish War of Independence, and on December 6 1921, the Irish Free State became independent. After a new constitution came into effect in 1937, the state became a republic. Northern Ireland stayed with the UK, and this would lead to The Troubles beginning in the 1960s and ending with the Good Friday Agreement signed in 1998.
Ireland is traditionally divided into four provinces and thirty-two counties. Twenty-six counties are in the Republic and six in Northern Ireland. Three of the provinces are entirely within the Republic (Connacht, Leicester and Munster), and one province (Ulster) has some counties in both the Republic and in Northern Ireland.
Dublin is the largest city. It is the capital of the Republic of Ireland. Dublin was established as a Viking settlement in the 9th century. The population is 525,383 in Dublin City, and 1,270,603 in Co. Dublin.
Belfast is the capital of Northern Ireland. It has 483,000 people in the Greater Belfast urban area there are 267,000 in the city itself. Shipbuilding used to be a major industry here. The "Titanic" was built in Belfast at the Harland and Wolff shipyard.
Armagh is a city in Northern Ireland. It is often called the 'Ecclesiastic Capital of Ireland' as it is the seat of both the Catholic Church and the (Protestant) Church of Ireland. The population is 14,590.
Cork is the largest city in Munster. Corkonians often refer to it as 'the Real Capital'. The population is 119,230. but following a 2019 Cork boundary change|boundary extension in 2019, the population increased to c. 210,000.
Derry is the second largest city in Northern Ireland. Derry is notable for the Medieval city walls which still stand. Because the walls have never been breached, the city is nicknamed "The Maiden City". In 2013 Derry was the UK Capital of Culture. Many cultural events took place there during the year. The population is 83,652.
During the last glacial period (the "ice age"), most of Ireland was covered with ice. After that, Ireland became covered with trees. The first people came to Ireland about 9,000 years ago, in the Middle Stone Age (Mesolithic period). They were nomadic. Once food ran out in the place they lived, they would move to another place. Evidence of these people was found in Mount Sandel, Co. Derry.
About 4000 BC, in the New Stone Age (Neolithic period), the first farmers arrived in Ireland. These people cleared openings in the forest and built permanent settlements with houses and farmland. When people in this age died, they were buried in tombs called megaliths. Many megaliths are left standing today, such as portal dolmens and passage tombs.The most famous megalith is Newgrange passage tomb in co.Meath.
New settlers came around 2000BC, marking the start of the Bronze Age. Copper was mined mainly in Mount Gabriel, Co. Cork and tin was imported from Cornwall. These people used bronze to make weapons, such as swords. They also used it to make early forms of jewellery, such as sun discs and torcs. These settlers buried the dead in court tombs or wedge tombs, and burial places have been found with stone circles.