Human:

A human or human being is a person. Humans are often called "people". Humans are part of the species Homo sapiens which means 'wise man' in Latin.^[1] Humans are bipedal which means they walk on two legs. Humans have a complex brain which makes them able to use language, emotion and abstract reasoning. This brain and the fact that arms are not needed for walking make humans more able to use tools than any other species. Humans are now the dominant species on planet Earth with over 6.7 billion people as of 2008.^[2] There are humans living on every continent,^[3] and there are also humans living in space in the International Space Station which orbits the Earth.

Humans are part of the animal order of primates. Apes are also primates, and are the nearest animal relations to humans. Humans, like other primates, are social animals which usually live in groups, helping and protecting each other, and caring for their offspring (children). Many animals use sounds for social communication with each other. Humans are better at this than any other animal, and communicate with each other by language (words).

Origins

Humans are part of the animal kingdom. They are mammals, which means that they give birth to their young ones, rather than laying eggs like reptiles or birds, and the female humans are able to feed their babies with breast milk. Humans belong to the order of primates. Apes like gorillas and gibbons are also primates. The closest living relatives of humans are the two chimpanzee species: the Common Chimpanzee and the Bonobo. Scientists have examined the genes of humans and chimpanzees, and compared their DNA. The studies showed that between 95% and 99% of the DNA of humans and chimpanzees is the same. ^[4] ^[5]^[6]^[7]^[8]

One way that scientists use to explain the similarity between humans and other primates such as Chimpanzees is the Theory of Evolution. In the Theory of Evolution, it is thought that humans, chimpanzees, and gorillas have a common type of ancestor primate. In 2001, a hominid skull was discovered in Chad. The skull is about 7 million years old, and has been classified as Sahelanthropus tchadensis. The skull may show that the date at which humans started to evolve (develop differently) from other primates is 2 million years earlier than scientist thought it was.^[9]

Humans are part of a genus called homonidae (or homonids). This comes from the Latin homo for human. Thousands of years ago, there used to be other types of hominids on Earth. They were like modern humans, but not the same. Homo sapiens are the only type of hominids who are alive today. The earliest-known fossils of genus homo have been named Homo habilis (handy man). The first fossils of Homo habilis were found in Tanzania between 1962 and 1964. Homo hablilis is thought to have lived about 2.2 to 1.7 million years ago.^[10] Another human species thought to be an ancestor of the modern human is Homo erectus. Scientists are still discussing whether Homo erectus really descended from Homo habilis. They think it may also be possible that both came from a common species of human that they don't know about yet.^[11] There are many different extinct species of homo known today. Many of them were likely our "cousins", as they developed differently than our ancestors.^[12]

A theory called the Sahara pump theory has been used to tell how difference species of plants and animals moved from Africa to the Middle East, and then elsewhere. Early humans may have moved from Africa to other parts of the world in the same way. The first truly modern humans seem to have appeared between 200,000 and 130,000 years ago.^[13]^[14] These early humans moved out from Africa and by 10 thousand years ago they lived in most parts of Asia, Europe, Africa and North America.^[15] They replaced other groups of human like species that had migrated earlier. These were called Neanderthals or Homo erectus. They competed for resources with the modern human, but the modern human was more successful.

Civilisation

Up to about 10 thousand years ago most humans were hunter-gatherers. That means they hunted for their food or gathered it from wild plants. Most humans at this time did not live in one place, but moved around as the seasons changed. The start of planting crops for food, called farming, meant that some people chose to live in static settlements. This also lead to the invention of metal tools and the training of animals. About 6000 years ago the first proper civilisations began in places like Egypt, India and Syria. The people formed goverments and armies for protection. They competed for area to live and resources and sometimees they fought with each other. About 4000 years ago some states took over or conquered other states and made empires. Examples include ancient Greece and the Roman Empire.

Some modern day religions also began at this time such as Judaism and Hinduism. From the Middle Ages and beyond humanity saw an explosion of new technology and inventions. The printing press, the car, the train and electricity are all examples of this kind of invention. As a result of all this modern humans live in a world where everyone is connected, be that by telephone or by internet or any other way. People now control and change the enviroment around them in many different ways.

Habitats, settlements and population

Early human settlements were mostly based around being near to water and other natural resources. In modern times if people need things they can transport them from somewhere else. So basing a settlement around where resources are is no longer as important as it was. Since 1800 the number of humans, or population, has increased by six billion.^[16] Most humans (61%) live in Asia. The rest live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%).

In 2004 39% of all people lived in towns and cities. This number is expected to get higher. In 2008 the UN said that over half the world would be living in towns or cities by the end of the year.^[17]

Humans have a large effect on the world. Humans are at the top of the food chain and are generally not eaten by any animals. Humans have been described as Super Predators because of this.^[18] Because of industry and other reasons humans are said to be a big cause of global climate change. ^[19]

Biology

Physical appearance

human body types can be very different from each other. The average height of an adult human is between 5 and 6 feet. The average weight is between 76 and 83 kg for males and 54-64 kg for females.^[20]

Human hair grows on the underarms, the genitals and the top of the head in both genders, and on the chest, legs, back and face of males. Although it might look like humans have less hair than most primates they actually don't. The average human has more hair folicles, where hair grows from, than most chimpanzees. ^[21] Human hair can be brown, red, blonde or most commonly black. ^[22] Modern humans can also have their hair in many different colours by using dye. When humans get older hair can turn grey or even white.

Human skin colours vary greatly. They can be a very pale pink all the way up to dark brown. Human skin can get darker when under sunlight.^[23] Sunlight is part UV radiation. The UV radiation in the light makes the skin change colour over a long time. This is called a sun tan.

Humans are not as strong as other primates the same size. An average female orangutan is at least three times as strong as an average human man.^[24]

The average human male needs 7 to 8 hours sleep a day. People who sleep less than this are generally not as healthy. A child needs more sleep, 9 to 10 hours on average.

Life cycle

The human life cycle is quite like most other mammals. The young grow inside the female mother for nine months. After this time the baby is pushed out of the womans vagina. Unlike most other animals human childbrith is quite dangerous. Because human brains are so big baby's heads are wide. The mothers pelvis bones are also not very wide because people walk on two legs. This combination means that quite often either mother and/or baby die in childbirth.^[25] The number of mothers dying in childbirth is less in the 21st century. This is because of better medication and treatment. In many poor countries the number of mothers dying is very high. Sometimes it is up to 10 times as many as richer countries.^[26]

The average human baby weighs 3 – 4 kg at birth and is 50-60 cm tall. This is often less in poorer countries.^[27] Many babies in poor countries often die early because of this.^[28]

Life expectancy is how long you are expected to live for. This depends on many things including where you live. The highest life expectancy is for people from Hong Kong, (84.8 years). The lowest is for people from Swaziland where, mainly beacuse of AIDS, life expectancy is only 31 years.^[29]

Psychology

Psychology is the study of how the human mind works. The human brain controls everything the body does. Everything from moving and breathing to thinking is done by the brain. Neurology is the study of how the brain works, psychology is the study of how and why people think and feel.

Human behaviour is hard to understand, so sometimes psychologists study animals because they may be simpler and easier to understand. Psychology overlaps with many other sciences including Medicine, Biology, Computer Science and Linguistics.

Culture

Language

Language at its most basic is talking, reading and writing. The study of language is called linguistics. Humans have the most complicated languages on Earth. Human language is much more complicated than any other species.^[30] There are 7,300 languages spoken around the world as of 2008.^[31] The worlds most spoken language as of 2008 is Mandarin Chinese. Over a billion people (1/6 of the world) speak this language.^[32]

Art, music and literature

Art has existed almost as long as humans. People have been doing some types of art for thousands of years as the picture on the right shows. Art represents how someone feels in the form of a painting, a sculpture or a photograph.

Music has also been around for thousands of years. Music can be made with only your voice but most of the time people use instruments. Music can be made using simple instruments only such as simple drums all the way up to electric guitars, keyboards and violins. Music can be loud, fast, quiet, slow or many different styles. Music represents how the people who are playing the music feel.

Religion and spirituality

Religion is the belief in a higher being, spirit or anything that there is no proof exists. Because there is no proof in these things people need faith. Faith can bring people together because they all believe in the same thing. Some of the things religions talk about are what happens after death, why humans exist, how humans began and what is good to do and not to do (morality). Some people are not religious, some people are very religious and some people believe a mixture of science and religion.

Science and technology

Technology is the things people make to help them do things. Science is understanding how the universe and the things in it work. Technology used to be quite simple. It was passed on by people telling other people, until writing was invented. This allowed technology to develop much quicker. Now people understand more and more about the world and the universe. The invention of the telescope by Galileo, Einstein's theory of relativity and the big bang theory are all big technological - to do with technology - discoveries. Technology has come forward enough to allow things such as the internet, space travel and television.

War

A war is a conflict between large groups of people, usually countries or states. A war always involves the use of lethal force as both sides try to kill each other. It is estimated that during the 20th century between 167 and 188 million humans died as a result of war.^[33] The people who fight in wars are called soldiers.

Modern wars are very different from wars a thousand or even a hundred years ago. Modern war involves, sabotage, terrorism, propaganda and guerilla warfare. In modern day wars civilians - people who are not soldiers - are often targets. An example of this is the atomic bomb dropped on Hiroshima and Nagasaki at the end of World War II. The bombs killed as many as 140,000 people in Hiroshima and 80,000 in Nagasaki by the end of 1945,^[34] roughly half on the days of the bombings. Since then, thousands more have died from injuries or illness attributed to exposure to radiation released by the bombs.^[35] In both cities, the overwhelming majority of the dead were civilians. In Germany, Austria, and Great Britain, conventional bombs were used. About 60,595^[36] british and 550,000 ^[37] German (and possibly Austrian) civillians were killed during bombings of cities from warplanes.

References

↑ homo sapiens.
↑ World pop clock.
↑ A Timeline of Life.
↑ By using genome sequencing, scientists have compared:
1. The difference between two humans that are related
2. The difference between two humans that are not related
3. The difference between a human and a chimpanzee
4. The difference between two other animals that look like each other- rats and mice
The studies showed that, after 6.5 million years of evolution as separate species, between 95% and 99% of the DNA of humans and chimpanzees is the same. The difference between a human and a chimpanzee was about ten times greater than the difference between two unrelated humans. When this difference is compared with the difference between the DNA of mice and rats, the difference between a mouse and a rat is ten times greater than the difference between a human and a chimpanzee.
↑ de Wal, Frans (1997). Bonobo. University of California Press. ISBN 0-520-20535-9. [1]
↑ Britten RJ (2002). "Divergence between samples of chimpanzee and human DNA sequences is 5%, counting indels". Proc Natl Acad Sci U S A 99 (21): 13633–5. DOI:10.1073/pnas.172510699.
↑ Wildman, D., Uddin, M., Liu, G., Grossman, L., Goodman, M. (2003). "Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: enlarging genus Homo". Proc Natl Acad Sci U S A 100 (12): 7181–8. DOI:10.1073/pnas.1232172100.
↑ Ruvolo M (1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets". Mol Biol Evol 14 (3): 248–65.
↑ Brunet, M., Guy, F., Pilbeam, D., Mackaye, H., Likius, A., Ahounta, D., Beauvilain, A., Blondel, C., Bocherens, H., Boisserie, J., De Bonis, L., Coppens, Y., Dejax, J., Denys, C., Duringer, P., Eisenmann, V., Fanone, G., Fronty, P., Geraads, D., Lehmann, T., Lihoreau, F., Louchart, A., Mahamat, A., Merceron, G., Mouchelin, G., Otero, O., Pelaez Campomanes, P., Ponce De Leon, M., Rage, J., Sapanet, M., Schuster, M., Sudre, J., Tassy, P., Valentin, X., Vignaud, P., Viriot, L., Zazzo, A., Zollikofer, C. (2002). "A new hominid from the Upper Miocene of Chad, Central Africa". Nature 418 (6894): 145–51. DOI:10.1038/nature00879.
↑ New York Times article Fossils in Kenya Challenge Linear Evolution published August 9, 2007 says "Scientists who dated and analyzed the specimens — a 1.44 million-year-old Homo habilis and a 1.55 million-year-old Homo erectus — said their findings challenged the conventional view that these species evolved one after the other. Instead, they apparently lived side by side in eastern Africa for almost half a million years."
↑ F. Spoor, M. G. Leakey, P. N. Gathogo, F. H. Brown, S. C. Antón, I. McDougall, C. Kiarie, F. K. Manthi & L. N. Leakey (9 August 2007). "Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya". Nature 448 (448): 688–691. DOI:10.1038/nature05986.
↑ Strait DS, Grine FE, Moniz MA (1997). "A reappraisal of early hominid phylogeny". J. Hum. Evol. 32 (1): 17–82. DOI:10.1006/jhev.1996.0097.
↑ Human Ancestors Hall: Homo Sapiens - URL retrieved October 13, 2006
↑ Alemseged, Z., Coppens, Y., Geraads, D. (2002). "Hominid cranium from Omo: Description and taxonomy of Omo-323-1976-896". Am J Phys Anthropol 117 (2): 103–12. DOI:10.1002/ajpa.10032.
↑ Fossil Feces Is Earliest Evidence of North American Humans.
↑ World population reaches six billion.
↑ Half of humanity set to go urban.
↑ Evolution, IQ, and Domain General Mechanisms.
↑ [http://www.grida.no/climate/ipcc_tar/wg1/007.html Climate Change 2001: Working Group I: The Scientific Basis].
↑ Averages and Human Weight.
↑ Why Humans and Their Fur Parted Way by Nicholas Wade, New York Times, August 19 2003.
↑ Rogers, Alan R., Iltis, David & Wooding, Stephen (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology 45 (1): 105–108. DOI:10.1086/381006.
↑ Harding, Rosalind M., Eugene Healy, Amanda J. Ray, Nichola S. Ellis, Niamh Flanagan, Carol Todd, Craig Dixon, Antti Sajantila, Ian J. Jackson, Mark A. Birch-Machin, and Jonathan L. Rees (2000). Evidence for variable selective pressures at MC1R. American Journal of Human Genetics 66: 1351 – 1361.
↑ Schwartz, Jeffrey (1987). The Red Ape: Orangutans and Human Origins, pp.286. ISBN 0813340640.
↑ According to the July 2, 2007 Newsweek magazine, a woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in Africa, compared to 1 in 2,800 in developed countries
↑ Rush D (2000). "Nutrition and maternal mortality in the developing world". Am J Clin Nutr 72 (1 Suppl): 212 S–240 S.
↑ Big Birth Weight Babies.
↑ Khor G (2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Med Coll J 5 (2): 113–22.
↑ [www.cia.gov/library/publications/the-world-factbook CIA - The World Factbook].
↑ Collins, Desmond (1976). The Human Revolution: From Ape to Artist, pp.208.
↑ List of Languages.
↑ The 30 Most Spoken Languages of the World.
↑ Ferguson, Niall. "The Next War of the World." Foreign Affairs, September/October 2006
↑ Frequently Asked Questions #1. Radiation Effects Research Foundation. Retrieved on 18 September 2007.
↑ Rezelman, David; F.G. Gosling and Terrence R. Fehner (2000). THE ATOMIC BOMBING OF HIROSHIMA. The Manhattan Project: An Interactive History. U.S. Department of Energy. Retrieved on 18 September 2007. page on Hiroshima casualties.
↑ Matthew White Twentieth Century Atlas - Death Tolls: United Kingdom lists the following totals and sources:
- 60,000, (bombing): John Keegan The Second World War (1989);
- 60,000: Boris Urlanis, Wars and Population (1971)
- 60,595: Harper Collins Atlas of the Second World War
- 60,600: John Ellis, World War II : a statistical survey (Facts on File, 1993) „killed and missing“
- 92,673, (incl. 30,248 merchant mariners and 60,595 killed by bombing): Encyclopaedia Britannica, 15th edition, 1992 printing. „Killed, died of wounds, or in prison .... excluding those who died of natural causes or were suicides.“
- 92,673: Norman Davies,Europe A History (1998) same as Britannica's war dead in most cases
- 92,673: Michael Clodfelter Warfare and Armed Conflict: A Statistical Reference to Casualty and Other Figures, 1618-1991;
- 100,000: William Eckhardt, a 3-page table of his war statistics printed in World Military and Social Expenditures 1987-88 (12th ed., 1987) by Ruth Leger Sivard. „Deaths“, including „massacres, political violence, and famines associated with the conflicts.“
The British kept accurate records during WWII SO 60,595 was the official death toal with 30,248 for the British merchant mariners (most of whom are listed on the Tower Hill Memorial)
↑ German Deaths by aerial bombardment (It is not clear if these totals includes Austrians, of whom about 24,000 were killed (see Austrian Press & Information Service, Washington, D.C) and other territories in the Third Reich but not in modern Germany)
- 600,000 about 80,000 were children in Hamburg, Juli 1943 in Der Spiegel © SPIEGEL ONLINE 2003 (in German)
- Matthew White Twentieth Century Atlas - Death Tolls lists the following totals and sources:
  - more than 305,000: (1945 Strategic Bombing Survey);
  - 400,000: Hammond Atlas of the 20th Century (1996)
  - 410,000: R. J. Rummel, 100% Democide;
  - 499,750: Michael Clodfelter Warfare and Armed Conflict: A Statistical Reference to Casualty and Other Figures, 1618-1991;
  - 593,000: John Keegan The Second World War (1989);
  - 593,000: J. A. S. Grenville citing „official Germany“ in A History of the World in the Twentieth Century (1994)
  - 600,000: Paul Johnson Modern Times (1983)

Human

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