Human Definition and 895 Threads

Humans (Homo sapiens) are the most abundant and widespread species of primates, characterized by bipedality and large complex brains enabling the development of advanced tools, culture and language. Humans are highly social beings and tend to live in large complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Curiosity and the human desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of knowledge.
Humans evolved from other hominins in Africa several million years ago. Although some scientists equate humans with all members of the genus Homo, in common usage it generally refers to Homo sapiens, the only extant member. H. sapiens emerged around 300,000 years ago, evolving from Homo erectus and migrating out of Africa, gradually replacing local populations of archaic humans. Early humans were hunter-gatherers, before settling in the Fertile Crescent and other parts of the Old World. Access to food surpluses led to the formation of permanent human settlements and the domestication of animals. As populations became larger and denser, forms of governance developed within and between communities and a number of civilizations rose and fell. Humans have continued to expand, with over 7.8 billion humans occupying almost all regions of the world in 2021.
Genes and the environment influence human biological variation in visible characteristics, physiology, disease susceptibility, mental abilities, body size and life span. Though humans vary in many traits (such as genetic predispositions and physical features), two humans on average are over 99% similar, with the most genetically diverse populations from Africa. The greatest degree of genetic variation exists between males and females. On average, men have greater body strength and women generally have a higher body fat percentage. Females undergo menopause and become infertile decades before the end of their lives. They also have a longer life span in almost every population around the world. The division into male and female gender roles has varied historically, and challenges to predominant gender norms have recurred in many societies.
Humans are omnivorous, capable of consuming a wide variety of plant and animal material, and have used fire to prepare and cook food since the time of H. erectus. They can survive for up to eight weeks without food, and three or four days without water. Humans are generally diurnal, sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death. Both the mother and the father provide care for human offspring who are helpless at birth.
Humans have a large and highly developed prefrontal cortex, the region of the brain associated with higher cognition. They are intelligent beings, capable of episodic memory, flexible facial expressions, self-awareness and a theory of mind. The human mind is capable of introspection, private thought, imagination, volition and forming views on existence. This has allowed great technological advancements and complex tool development possible through reason and the transmission of knowledge to future generations. Language, art and trade are defining characteristics of humans. Long-distance trade routes might have led to cultural explosions and resource distribution that gave humans an advantage over other similar species.

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  1. P

    Is Human Life Hopeless? Finding Purpose and Meaning in Existence

    Human Life... Hopeless? Social morals for me are like driftwood being carried in from generation to generation - always changing positions, because it lacks the ability to control itself - like most humans I meet these days. I firmly believe that you should treat others the way you want to...
  2. C

    Why does the human body need iron?

    As far as I know Iron is used in many enzymes as the metal complex. Beyond this are there any biological uses for iron? All uses appreciated, ty.
  3. K

    A Model of Human Population Growth: Is a Breaking Point Coming?

    i was just wondering abt this thing for a while... the total no. of human beings are increasing over the decades...which means some %ge of the Earth's matter is getting converted in the form of humans...suppose if the population goes on increasing, then theoretically there should be only humans...
  4. K

    What is the word for a situation of perpetual motion?

    In need of a human Dictionary! OK - I somehow have forgotten my favorite word. I have used it for years, but for the past week it has completely slipped my mind. To all you intellectuals - please help me remember what the word is. OK - The word is used in describing a situation of perpetual...
  5. G

    Human powered still - Nichrome wire

    The ASME design competition is to design a human powered still... basically to use human power to boil water. We have a bike running a DC motor, producing a range of 100-250 watts (depending on pedal speed, we need to test this). To convert this to electricty, we were thinking of using...
  6. P

    Human interaction for personal gain

    Human interaction for personal gain of each individual.Is that the best summary of interaction between individuals.
  7. V

    Medical Difference between a computer and the human brain

    Isn't the main difference between a computer and the human brain this: a computer uses a programme to process data but the human brain processes data and processes programmes which process data (to improve the data processing programmes and thus increase the brain's effectiveness and...
  8. E

    The human body as a radiator - Air conditioning

    After reading the thread "how many watts does the human body use?" I calculated that my body requires 86 W of energy on average throughout the day. However, I am wondering how much excess energy my body radiates as waste heat (and blackbody radiation) ? Obviously this depends on a lot...
  9. C

    Human enchancement. Should it be done?

    For a little I have been wondering about whether it is better for humanity to embrace human enchancement technologies. I can't come to any conclusion, because there seem to be valid arguments on both sides. Valid For: quality of life can improve because people see the world a little more...
  10. M

    Exploring Human Perception: How Do We Communicate?

    Hello, Nowdays I'm getting confused about what happens when our perceptions are not the same as the other? As it has been discused before in this forum, Two objects can never be exactly the same as the other, which is completely logical. As a result the perception of two different human...
  11. H

    Medical Human Brain vs. Quantum Computer

    Do you think the human brain is best described a) Quantum computer b) Classical computer c) Semi-classical computer d) None of the above Cheers
  12. S

    How Much Power Can the Human Body Output?

    Does anyone know how much power can the human body output? Specifically, how much power can each part of the body output? e.g. how much power can an arm output, a leg output, a particular muscle output, etc? Thanks, sphoenixee
  13. S

    Can People Fly? Investigating Human Flight Possibilities

    Stupid question: can people fly? Evidently, one doesn't see people flying around the streets, but is it possible? Has anyone done studies on whether this is possible or not? Any articles on this would be highly appreciated. Has anyone actually done this? Furthermore, how does physics apply to...
  14. C

    How many watts does the human body use

    how many watts does the human body use i guess 500w
  15. -Job-

    Human Computation: Google Tech Talk

    The following tech talk at google discusses using humans to collect useful information for things such as images, using games. It's an interesting approach, which certainly makes a lot of sense. http://video.google.com/videoplay?docid=-8246463980976635143&q=techtalk&hl=en
  16. A

    Medical The Human Mind and Predicting Behavior

    http://dsc.discovery.com/news/2006/08/16/mindreading_hea.html?category=health&guid=20060816103000 Very interesting article. This could be the beginning of something big, the way I see it. The reason why I found this article so interesting is because it seems to be the first time we have...
  17. N

    Need Info On The Human Genome Project

    I Need some con/bad things about this here topic..Can anybody help??
  18. Evo

    Tragic Elevator Accident at Ohio State University Leaves One Student Dead

    Student crushed to death when 24 Ohio State students crowd onto dorm elevator. "The 2,500-pound weight capacity of the elevator was exceeded by as much as 1,100 pounds, said Doug Smith, a battalion chief for the Columbus Division of Fire." The human capacity for idiocy continues to astound...
  19. S

    Center of mass of the human figure

    The drawing shows a human figure approximately in a sitting position. For the purposes of this problem, there are three parts to the figure, and the center of mass of each one is shown in the drawing. These parts are: (1) the torso, neck, and head (total mass = 41.5 kg) with a center of mass...
  20. C

    Future Human: Making human's invisible without a suit

    Greetings, in the physics forum we've had a discussion on how to make a person invisible. Many people suggested complicated invisibility suits which I won't get into. I had an idea of how we could possibly biologically engineer a human body to be invisible without the need for a suit. I'm...
  21. B

    Estimating Volume of an Average Adult Human

    For a current assignment i am trying to determine the volume of an average adult human in metres cubed. My strategy is to mulitply the average hieght by wast circumfrance for a rough estimate and convert to metres however i am having a hard time findng the average waist size. i found that...
  22. C

    Average Atomic mass of the human body?

    I was wondering average atomic mass is of a fully grown male human. What I mean by this is, if we consider the human body to be comprised of mainly Carbon, Hydrogen, Oxygen, Nitrogen and other trace elements like Calcium, Sodium, Phosphorus, etc. Is it possible to determine an estimate about...
  23. K

    How do vaccine work in the human body?

    how does vaccine help the body develop the immunity that it needs?
  24. D

    Lowest Light Intensity Stimulating Human Eye - Wavelengths

    What is the lowest intensity of light that generates any stimulus in the human eye? In what wave length range?
  25. T

    Exploring Absurdity of Human Ethics

    What do people mean when they say they are arguing from a moral point of view? Are moral views there, existing but consealed in our brain? do we have an inner idea of what ethical view like justics is suppose to be? For myself, i think judging each person in his or her own term is a ethical...
  26. B

    Human Conduction: Exploring Electric Shock

    Hi folks, I was just looking into conduction as part of an electric shock, as in, the flow mechanism, when I ran across an article about such things, which states: "However, NO ELECTRONS FLOWED THROUGH YOUR BODY AT ALL. The electric charges in a human body are entirely composed of positive...
  27. S

    What Causes Spontaneous Human Combustion?

    Does anybody has any comment on this? What might cause it? B/c I don't want to explode. lol
  28. T

    How Do You Calculate the Moment of Inertia for a 5'10, 165lb Male?

    I am having a lot of trouble trying to find the moment of inertia of myself, a male 5'10", and 165lbs. It seems as if it should be simple but am unsure how to take this one on. Any help would be great thanks.
  29. S

    Learn the Science Behind Human Hair and Its Unique Properties

    why when you cross the 2 hairs http://img148.imageshack.us/img148/8223/image15dz.png the moment you try to break them up, you would see like they are "somehow connected", is that "static electric" ?
  30. O

    The Platonic World. Real or a human construct?

    Does the abstract mathematical world exist independently of the physical world? Roger Penrose, the author of "The Road to Reality", regards this as part of the Platonic world — and seems to incline to the view that it does have an independent existence, as some kind of eternal truth. I'd...
  31. S

    Can the human body influence electronics?

    I've never been to this forum before but I was googling the hutchison effect and also info about radio waves and the human body and that's how I found this place. I've read a topic dating back to 2004 and made me wonder if the human body can influence electronics like causing interference and...
  32. A

    How many atoms in a human cell?

    How many atoms could fit inside a human cell? "A person's body is actually made up of trillions of cells (source: Science Concepts - Cells by Silverstein)", but how many atoms could fit inside a human cell? 125 million atoms could fit inside the period at the end of this sentence. But how...
  33. J

    Exploring the Limits of Human Morals

    I understand the moral stands of Absolutism, Objectivism and Realism now what i am wondering, is their a stand that says humans have no morals at all and we just fool ourselves into thinking what is right and wrong, or is this in one of the ones i named above and I should just learn them better...
  34. Amith2006

    How Do You Calculate the Power of a Human Heart Pumping Blood?

    Sir, Please help me with this problem. # The heart of a man pumps 4 litres of blood per minute at a pressure of 130 mm of mercury. If the density of blood is 13.6 gm/cc, what is the power of the heart?
  35. iansmith

    Human and chimp genomes reveal new twist on origin of species

    http://www.eurekalert.org/pub_releases/2006-05/biom-hac051106.php
  36. E

    Can You Beat a Machine in IQ Test-Like Games?

    In this page you can play against a machine in IQ test-like games. Very funny. www.theiqchallenge.com
  37. Hootenanny

    Average Human Reaction Time to Visual Stimulus

    I was wondering if anyone knows of a site that gives the average reaction time for a human. I'm looking for something which relates to someone stopping a stopwatch when a visual stimulus is seen? Any help would be appreciated.
  38. A

    Human Eye Resolution: Testing Light Levels

    hi, I've just done an experinemt to try and show the resolution of the human eye in different light levels. i did it by putting a 0.25mm apart slits in a tube then, behind it had an adjustbable light, then i moved the slit further back, and asked them to say if they could see the two slits...
  39. M

    Human Body Levers: Exploring First and Second Class

    I know that the human body is mostly made of third class levers, making it fit for speed. What would happen if the human body were made of first or second class levers?
  40. S

    Medical Human Stress Reaction: Mind Changes Explored

    Hello I mentioned this in General Discussion, but perhaps I can get some answers here. In the human stress reaction, the blood flows away from the skin and fat is dumped into the blood stream. The the removing of blood away from the skin allows the person a better chance of surviving in case of...
  41. L

    Regarding human influence and Heisenberg

    Ok...I'm new to these forums and am just beginning to understand quantum physics, so please be kind. I've been reading those Brian Greene books and I have a question that I don't think he addressed. If I understand correctly, some believe that IF we could measure the position, velocity and...
  42. O

    Is Capitalism the Natural Evolution of Human Society?

    Capitalism to me seems to be a natural development for humans. It's almost the only economical system where each person has an alleged equal chance at success. But is society built the right way? If we look historically on the psychological side of it, capitalism was a way to let people have...
  43. P

    Human civilisation in 1.5 billion years

    I once read a story on the internet, written by a supposed alien abductee, who said that intelligent insectoids will walk on Earth in 1.5 billion years and find no evidence that humans ever existed. :biggrin: My question is: If all humans were to go extinct right now, what would be left of...
  44. J

    The DNA of Eve: Uncovering the Mystery of Human Origins

    It is my understanding that the DNA guys have concluded that all Homo sapiens originated as progeny of a single "Eve" in Central(?) Africa. Since I haven't heard anything about "Adam," I assume that the genetic tracers don't allow anything to be said about the male lineage. Be that as it may...
  45. S

    Will human beings destroy the earth

    Do you think, in 200 years time, will human beings destroy the Earth and their own civilization?
  46. E

    Exploring Pressure on Human Bones and Giant Leg Strength

    Hi Two questions, a) how does pressure (in N/cm^2) on the cross section of a human bone change if the length (i'm assuming the length of the person) would increase 10 times ? b) How big would a giant have to be so it's legs can support a pressure of 1000 N/cm^2 with a cross section area of 8...
  47. B

    Surviving Evolution: The Ongoing Battle Between Pathogens and Human Immunity

    I have been thinking of the evolution of the human race over time. Obviously, environmental factors have prevented those with detrimental traits from passing them on, bringing us to our current form. However, with the amount of technological advances in our current time and in the near future...
  48. Ivan Seeking

    Medical Are Mice with Human Brain Cells Ethically Acceptable?

    http://pittsburghlive.com/x/tribune-review/health/s_403491.html
  49. S

    Mathematica Mathematical formula of a human being

    Mathematical formula of a human being (in biological terms (molecules, cell structures, cell arrangment, types of cells and their relations - natural laws by which human being is 'generated' etc))... (inspiration: fractals) (less complex formula giving structural information for everything...
  50. wolram

    Is human evolution at a standstill?

    http://www.guardian.co.uk/Archive/Article/0,4273,4348751,00.html For those who dream of a better life, science has bad news: this is the best it is going to get. Our species has reached its biological pinnacle and is no longer capable of changing. That is the stark, controversial view of a...
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