Sinodonty and Sundadonty

Sinodonty and Sundadonty are two patterns of features widely found in the dentitions of different populations in East Asia. These two patterns were identified by anthropologist Christy G. Turner II as being within the greater "Mongoloid dental complex". Sundadonty is regarded as having a more generalised, Australoid morphology and having a longer ancestry than its offspring, Sinodonty.

The combining forms Sino- and Sunda- refer to China and Sundaland, respectively, while -dont refers to teeth.

Description

Turner found the Sundadont pattern in the skeletal remains of Jōmon people of Japan, and in living populations of Taiwanese aborigines, Filipinos, Indonesians, Thais, Borneans, Laotians, and Malaysians.

By contrast, he found the Sinodont pattern in the Han Chinese, in the inhabitants of Mongolia and eastern Siberia, in the Native Americans, and in the Yayoi people of Japan.

Sinodonty is a particular pattern of teeth characterized by the following features:

Kennewick Man

Kennewick Man is the name generally given to the skeletal remains of a prehistoric Paleoamerican man found on a bank of the Columbia River in Kennewick, Washington, on July 28, 1996. It is one of the most complete ancient skeletons ever found. Radiocarbon tests on bone have shown it to date from 8.9k to 9k calibrated years before present.

The discovery of the remains led to considerable controversy, as the Umatilla people and other tribes have wanted the remains returned to them for reburial under the federal Native American Graves Protection and Repatriation Act (NAGPRA). The law was designed to remedy long-standing wrongs done to tribes and to facilitate the return of human remains and cultural objects unlawfully obtained taken from them. In this case, the archaeologist who discovered the bones, James Chatters and Douglas Owsley an archaeologist at the Smithsonian, both asserted that the bones were unrelated to today's Native Americans but instead had features that more closely resembled Polynesian or Southeast Asian peoples, a finding that would exempt the bones from NAGPRA.

Spirit Cave, Thailand

The Spirit Cave (Thai: ถ้ำผีแมน, tham phi maen) is an archaeological site in Pang Mapha district, Mae Hong Son Province, northwestern Thailand. It was occupied from about 9000 until 5500 BCE by the Hoabinhian.

Location

The site is at an elevation of 650 m on a hillside overlooking a small stream. The Salween River, one of Southeast Asia's longest rivers, is less than 50 km (31 mi) to the north. It was excavated in the mid-1960s by Chester Gorman. Two other significant sites nearby are the Banyan Valley Cave and the Steep Cliff Cave.

New Stone Age

The site dates from the Neolithic or New Stone Age, a period in the development of human technology that is traditionally the last part of the Stone Age. Beginning with the rise of farming, which produced the "Neolithic revolution" and ending when metal tools became widespread in the Copper Age (chalcolithic) or Bronze Age

Plant domestication

Gorman claimed that Spirit Cave included remains of Prunus (almond), Terminalia, Areca (betel), Vicia (broadbean) or Phaseolus, Pisum (pea) or Raphia Lagenaria (bottle gourd), Trapa (Chinese water chestnut), Piper (pepper), Madhuca (butternut), Canarium, Aleurites (candle nut), and Cucumis (a cucumber type) in layers dating to c.9800-8500 BCE. None of the recovered specimens differed from their wild phenotypes. He suggested that these may have been used as foods, condiments, stimulants, for lighting and that the leguminous plants in particular "point to a very early use of domesticated plants". He later wrote that "Whether they are definitely early cultigens remains to be established... What is important, and what we can say definitely, is that the remains indicate the early, quite sophisticated use of particular species which are still culturally important in Southeast Asia".

North America

North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.

North America covers an area of about 24,709,000 square kilometers (9,540,000 square miles), about 16.5% of the earth's land area and about 4.8% of its total surface. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia, Africa, and Europe.

In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7.5% of the world's population, if nearby islands (most notably the Caribbean) are included.

North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago (the beginning of the Archaic or Meso-Indian period). The Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the arrival of European settlers during the Age of Discovery and the Early Modern period. Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants. European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French and societies and states commonly reflect Western traditions.

Dental anatomy

Dental anatomy is a field of anatomy dedicated to the study of human tooth structures. The development, appearance, and classification of teeth fall within its purview. (The function of teeth as they contact one another falls elsewhere, under dental occlusion.) Tooth formation begins before birth, and teeth's eventual morphology is dictated during this time. Dental anatomy is also a taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment.

Usually, there are 20 primary ("baby") teeth and 28 to 32 permanent teeth, the last four being third molars or "wisdom teeth", each of which may or may not grow in. Among primary teeth, 10 usually are found in the maxilla (upper jaw) and the other 10 in the mandible (lower jaw). Among permanent teeth, 16 are found in the maxilla and the other 16 in the mandible. Most of the teeth have distinguishing features.

Growing of tooth

Tooth development is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. Although many diverse species have teeth, non-human tooth development is largely the same as in humans. For human teeth to have a healthy oral environment, enamel, dentin, cementum, and the periodontium must all develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth weeks in utero, and permanent teeth begin to form in the twentieth week in utero. If teeth do not start to develop at or near these times, they will not develop at all.