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.

View More On Wikipedia.org
  1. B

    More human population = greater mass?

    Hi everyone! This is my first post on this forum so please, if I have missed something please let me know! I have a lot of questions to ask but this is the main/first question in my mind right now! As I understand things, everything in the universe has mass (or anti-mass) and everything that...
  2. K

    Are His Points on Chromosome Fusion Valid?

    I was having a discussion about the evidence for and against evolution. I brought up the fact that Humans have one less pair of chromosomes as a result of the fusion of two ape chromosomes and all the evidence that supports this. Someone then told me that this is 'rubbish', because: 1) If a...
  3. A

    Do Thoughts Have Physical Mass?

    Hi, From what I understand, a thought is a series of electrical impulses. Does this mean that a thought has mass equivalent to the mass of an electron? Thanks,
  4. K

    Seaching for DC motor to be used as a human lift

    I am building a human lift for a vehicle. I am looking a for DC motor able to life 900 ft-lbs with a brake and the shaft is splined. Sending me a link to a company that sells this type of motor would be great. Thank you, Kevin
  5. C

    How does gravity affect the human body in different positions?

    Homework Statement i measured myself before going to sleep and after waking up over several nights and found out I'm ~1.5cm taller in the morning then at night. I know this question is related to human biology, but I'm equally (if not more so) interested in the physics behind the problem i.e...
  6. M

    All bones in human body are equal in strength.

    Why does many sites always said the femur is the strongest and heaviest bone in the human body? I know the femur is the longest bone, but is it really that the femur is the strongest and heaviest bone in human body? This is a link where it is said that human femur and humerus are nearly equal in...
  7. M

    How many amino acids are in the hemoglobin of humans, gorillas, and horses?

    I'm doing a lab and my biology teacher specifically told me to count the amino acids found in the hemoglobin of the aforementioned animals. Since I'm sure I'm not the only one who'd rather not count, and I cannot for the life of me find the numbers on the Internet, I figured I would post what...
  8. C

    Medical Is leisure time and recreation a fundamental human need?

    Hey! Do we really need recreation or leisure time to function as humans? Could one get away with it and just work all of his life to whatever purpose he/she is set to go for? How does one distinguish between work and leisure time? Was there such a distinction in early humans? Or did one such...
  9. L

    How Do Radio Waves Affect Human Tissue?

    I realize this might be a complicated question, but I can't seem to find any textbooks or papers that address this head on. Perhaps I am naive in this field. What happens to the electric and magnetic parts of a radio wave as it passes through the human body? As far as I understand: The...
  10. D

    News Kabbalah's description for the main human element.

    I've been reading a Kabbalah book written by Yehuda Berg. "The power of Kabbalah" And it's basically explaining the universe and everything about it from the text of the zohar. And the Kaballah explains in the first few pages that Humans main core element Is Desire and in the book it quotes "If...
  11. V

    Human Aura Photography: Learn What It Is & How It's Done

    Years ago in a science class we were shown a film that was suposidly showing footage of a special technique that was filming the human aura. (yes the same aura that psychics claim to see) Has anyone heard of this? Or better yet know what type of photography was used?
  12. S

    Are negri bodies seen in human who have died from rabies?

    My lec notes only specifies animal hippocampus, eg dog has this and unclear about humans. Humans do have this right, and it is a post mortem diagnostic method of rabies in humans right?
  13. rhody

    Cool Video, human powered flight, first video

    I confess, I stole this from garrett's twitter page, enjoy... Quoting the pilot's caption at the end: "and suddenly you are free, a really intense feeling of freedom. The true feeling of flying, a magical moment. The best feeling I have ever felt in my life" Rhody... :biggrin: :devil:
  14. F

    Is it possible for a person to function as a human ZIP/RAR data compressor?

    Is it possible for a person to function as a human ZIP/RAR data compressor? Memorize a small amount of data and then use an algorithm to extract it? Ok so I had a friend who stole the answer-key to a huge multiple-choice final exam, which took 3 hours to complete, and must have had hundreds...
  15. slider142

    Human Bird Wings: Is It Real or Fake?

    This video is very popular at the moment: http://m.wired.com/wiredscience/2012/03/human-bird-wings/ . While there are arguments stating that it is possible: http://gizmodo.com/5894904/man-flies-like-a-bird-flapping-his-own-wings , there are also some strange visual problems with the videos...
  16. C

    Medical What are Some Fields of Psychology that Focus on Predicting Human Behavior?

    I'm looking for a field of psychology which tries to predict human behaviour or sort of characterizes human beings based on their behaviour patterns. Honestly, I'm not sure what to call it, but I want to be able to say what a particular group of people will tend to like or dislike or what...
  17. J

    How fast can a human safley accelerate?

    In a straight line, on sea level (if it matters), how fast can a human safley accelerate? Not just the strongest human, but even the weakest, like an elderly or a child. Assume that they are strapped in a seat. I'm thinking about those maglev trains in air evacuated tunnels and how fast they...
  18. Dotini

    Human Eyes See Cosmic Bubbles that Algorithms Miss

    I thought this story was charming, since it hints that there still might be a few things people can do that computers cannot (yet) do. I have no idea of the significance of these bubbles, but I'd be interested to hear others comments...
  19. J

    Were There Ever Empirical Reasons to Bring Human Consciousness into QM?

    I'm wondering whether physicists in the 1930's ever had experimental reason to interpret, for example, Schrödinger's cat, as a true paradox (because of the role of a human observer). Why didn't they default to Bohr's interpretation, that an interaction with a geiger-counter, or any classically...
  20. S

    How Quantum Theory Explains Human Consciousness

    Hi, After some (limited) reading I've written an article on the captioned subject : http://3fathom.dyndns.org/QM-Consciousness.htm I post it here for feedback. Intellectual stimulation, please! Thanks, Stewart
  21. S

    Seeking career guidance: Networking or Human Resources as my Emphasis?

    Hey Folks, I am a new member to this forum. I am really in need of some guidance hope u people can help me out. I have 3 years of experience in IT Infrastructure ( like service desk, monitoring etc) I am unemployed for past 12 months. I am planning to pursue Graduate Management Certificate...
  22. R

    Reproduction and Human evolution

    Hey, I recently watched a video on YouTube by Kenneth Miller, The collapse of Intelligent Design. One of the things he brought up in the lecture was a comparison between. Human and chimpanzee genome. What was specifically said was that we had 23 pairs of chromosomes while the chimp and all...
  23. N

    Is a Human-Powered Refrigerator Feasible for Off-Grid Living?

    I make human powered machines for offgrid living and have been getting ready to start on a human powered fridge. The idea is to use a deep freezer and replace the compressor with an automotive one, and connect the shaft to pedals (might require two riders). 1) Are the freon types compatible...
  24. T

    Quantum Entanglement in a Human Brain

    Hi Do the experts on this forum think that it is possible for there to be special particles scattered throughout the volume of a living human brain which together form a single permanent quantum entanglement which lasts at least as long as the lifetime of the brain? If yes, what do you think...
  25. T

    Is the electric field in the human body zero?

    According to Gauss, a closed conducting body will distribute the charge to the surface. Since the human body is a conductor does that mean the electric field in our body is zero? :cool:
  26. T

    Can Pedal Power Be Used to Create a Human-Powered Air-Kart?

    First time posting, and I appreciate any replies. I've had a couple thoughts about building a small go-kart powered by a pneumatic motor. Please join me on a vision quest as I explain a few thoughts, and ask for advice: Assumption: 1 person through pedal power can exert between 100-300 watts...
  27. S

    Human Limitations of understanding.

    Do you think that there is a limit to Human comprehension. Will we ever be able to realize the true nature of reality. I don't mean to say that the standard model is wrong or anything like that, but there are parts that cannot be explained. Yet. I've read that when you come across...
  28. J

    Medical Human Perception of Matter and Energy via Five Senses

    Does this look accurate at all? Sense of Sight - The perception of energy (light waves) bouncing off of matter (solid/liquid/gas) Sense of Sound - The perception of energy (sound waves) traveling through matter (solid/liquid/gas) Sense of Taste - The perception of matter (solid/liquid) Sense of...
  29. Loren Booda

    Medical Mass of human brain vs. that of other nerves

    Which weighs more -- the human brain or the remainder of nerves in the human body?
  30. A

    Physics of Human Voice: Factors Affecting Volume

    Hi everyone. I have a basic question about the biomechanics of speech. If this is already answered please direct me to the solution. I'm trying to determine the main factors which determine the volume of a voice. What I think I know: when a human produces sound, air is forced out of lungs...
  31. L

    Are My Sci-Fi Population Estimates Realistic?

    Please forgive me if this fell into the wrong forum. I thought this would be the right place to ask. 500 million years have past since humanity came in control of a device that could send ships at great speeds across the universe, from the edge of one galaxy to the edge of another in weeks...
  32. S

    Can physics shed light on the nature of human consciousness ?

    Hi, fellow curious minds, I believe that human neuro structures are microscopic and thus within the realm of QM.From my basic physics knowledge, it seems to me that QM's probability interpretation of micro-phenomena is related to human volition. Every moment our consciousness are choosing...
  33. Ahmed Abdullah

    Is the sphincter in the human anus air-tight?

    Otherwise, why we don't stink all the time?
  34. B

    The human process 11 trillion bits per second

    I'm trying to figure out how many bits of information the human has stored in his mind. I personally believe that information is not stored in atoms in the person's brain but is stored in an immaterial realm and the information is not made of material. We can talk about whether or not that's...
  35. B

    Surviving Space: The Impact of Hemoglobin Levels on Human Body in a Vacuum

    Would someone with a disorder that results in the inability to carry the total of 4 hemoglobin per RBC survive longer in space without a suit (even if just a fraction of a second) than someone with 100% hemoglobin carrying potential due to their decreased O2 level?
  36. Q

    (21-23) thermodynamics problem. Finding efficiency for the human body

    Homework Statement While running up stairs at a (vertical) rate of 0.30 m/s, a man of 70 kg generates waste heat at a rate of 1300 J/s. What efficiency for the human body can you deduce from this? Homework Equations efficiency of heat...
  37. C

    The potential effects of Potassium chlorate on the human body.

    The potential effects of "Potassium chlorate" on the human body. To the many distinguished members of the chemistry field, I am a U.S. Army EOD (explosive ordnance disposal) Tech who returned from Afghanistan about 3 months ago. During my deployment I was forced to manually enter an IED...
  38. S

    Can a single human community exist without any disadvantages?

    I am not very well informed in this field but i want to know if there are any kind of genetic/biological problems humans might face ,if all the people(all races, religions etc) in the world start living as a single community? No higher organism has a single community stretching across the...
  39. E

    What refs describe ethics evolving from human needs and instincts?

    I am looking for references that explain how ethics evolved from human needs (e.g., community) and instincts (e.g., fight/flight).
  40. A

    My personal criticism to Quantum theory and Human conscience

    my personal criticism to "Quantum theory and Human conscience" I have to do a couple of premises: 1. There are some previous posts on this arguments, among them I found interesting this one: https://www.physicsforums.com/showthread.php?t=334994 2.This topic requires a deep knowledge in several...
  41. W

    Can a human travel to distant stars? And other questions.

    1. Can a human travel to distant stars? If the faster you go the slower the time passes for you, then you could technically travel to stars several thousands of years distant from you. It could take thousands of years for someone on Earth, but just a few days for you. 2. Why can't we travel...
  42. L

    Medical What happens to human consciousness once we pass away?

    So, as the title says, I'm curious to know what (theoretically) happens to human consciousness after we pass away. Obviously no one knows for sure, I'm just curious to learn more about this particular topic, from a scientific perspective. I'll admit, I'm curious about this because in July of...
  43. P

    Is there a limit to Human Lifespans?

    2,000 years ago the average life expectancy for humans was 19 years old. I mean, can you image having to kick the bucket before you’re even old enough to drink? 2,000 years later, with a little hand washing and a booster shot, you’ve got a pretty good chance of living to the ripe old age of...
  44. D

    Should machines replace human workers?

    The recession put people out of work, but when the recession weakens, there will be a huge incentive to replace what used to be workers with robots and IT. People who learned skills and worked for decades won't be getting their jobs back since those jobs won't exist. What are your thoughts on...
  45. Loren Booda

    Medical Has infrasound been used to image the human body?

    Is it possible to scan humans with ultra low frequencies to study medically one's physique?
  46. V

    Can dogs or cats survive in zero gravity without human assitance?

    The kinds of experiments involving animals in space have only answered simple questions of survivability in captivity where human assistance is at hand. The big problems of space colonization have yet to be answered. I thought up this question when someone on this forum posted a response to my...
  47. Y

    Exploring the Evolution of Human DNA

    I was reading articles regarding to the changing of human DNA and how our DNA seems to evolving a rapid rate. With this I wondered if the human DNA does evolve? and if so would DNA gain traits that we would now consider super human? Any info in this area would be appreciated.
  48. K

    Can the human mind be simplified to a binary model of ones and zeroes?

    First of all, I apologize if this issue has been covered before. Would it be accurate to say that, given that a neuron is either in a resting potential or action potential, that a binary model would be representative of the neural structure human mind, or would this be too simplistic of an...
  49. B

    How does the atmosphere affect human weight on Earth?

    Does Earth's thick layer of atmosphere push down on us, increasing our weights drastically?
  50. zoobyshoe

    Mark Twain's "The Damned Human Race" Performance

    I thought Penguino, Evo and others might enjoy this amazing performance of an excerpt from Mark Twain's essay: "The Damned Human Race". It's just a rant, but so entertainingly done I could say it's a demonstration of "The Art of Rant". https://www.youtube.com/watch?v=F_rTMNnxwSE
Back
Top