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. J

    Portal Discussion: Human at Speed of Light

    Hi all, I am very new to this forum so please let me know if I have posted this in the wrong place, and thanks in advance for any replies :) Backstory: My friends and I were playing a game called Portal in which you can place two portals (each of which leads to the other). We were...
  2. B

    SIR2: Could a Gene Extend Human Lifespan 6x?

    Could the exclusion of the SIR2 gene lengthen the human lifespan 6 times? it's been shown to lengthen lifespan like that in animals such as worms right?
  3. Ivan Seeking

    Medical First Zero-G Surgery Succeeds on Human Patient

    This story is a little over a year old but just came to my attention. http://space.newscientist.com/article/dn10169-doctors-remove-tumour-in-first-zerog-surgery-.html
  4. J

    Medical Top five pandemics we human beings are facing today

    What are top five pandemics that can't be cured today?
  5. J

    Medical The worst disease ever in human history

    WHat is the worst and formidable disease ever in human history? Why?
  6. D

    How does the weight distribution work in a human pyramid?

    Hi! I'm Simone, I come from Italy and I'm a newbie..glad to meet you...and ehm...I have already a question! My question is related about the example of human pyramid. There are 5 people, one at top of the other..like: o1 o2 o3 o4 o5 o5 push o4 up...o4 push o3 up and so on.. the...
  7. M

    Wooden Neurons: Will They Be Conscious?

    What if you have 10 foot neurons made of wood with mechanical clockwork innards, and they shoot different types of metal balls to each other to send messages. What if they have some mechanical method for reproducing every other function of a neuron? What if they are arranged in exactly the same...
  8. wolram

    How much methane can a cornish pasty produce?

    Theoreticaly if all one ate all day was a cornish pasty, how much methane could said pasty produce.
  9. Ivan Seeking

    Medical Can a human eye magnify an image?

    I once worked with a guy who had been hit in the head by lightning. As he described it, he was sitting on his porch and looking at a stop sign about a quarter-mile up the road. The last thing that he remembers - apparently at the moment of the strike - was the stop sign appearing to be...
  10. wolram

    What Is the Ideal Human Population and What Kind of World Is Possible?

    Does the human race------ Have a goal, other than an ever easier lifestyle, do you agree that we will never all be equally comfortable, do you agree that the Earth does not have the resources to make it so? In another thread the ideal population for Earth was guessed to be 2 billion, we are way...
  11. A

    MATLAB Human Heart Radiation Using Matlab

    Human Heart Radiation Using Matlab ( Electric Bipole ) Homework Statement Hey There, i was given a project saying : Use Matlab to simulate the radiation from a human heart ( Electric Diode ). What am i supposed to do? How to begin ? Thank You. Homework Equations The Attempt at...
  12. wolram

    Science or invention, which has contributed most to human comfort?

    Science or invention, which has contributed most to human comfort?
  13. S

    How Much Work is Done When Pushing a Sled with Different Friction Forces?

    Homework Statement A girl pushes her little brother on his sled with a force of 300N for 750m. How much work is done if the force of friction is a) 200N and b) 300N? Homework Equations W = F \Delta x The Attempt at a Solution F_{net} = F_p - F_f F_{net} = 300N - 200N = 100N...
  14. J

    Can a Human Fly? Calculating Wave Speed to Lift 75kg Weight

    Ok, propably everyone here knows that IN THEORY it is possible for a human to fly. This question has been bugging me a lot and I know it can be solved using some kind of aerial physics (Dont know the term :D). Therefore my question is: How fast must 75 kilograms weighing human wave his hands...
  15. Math Jeans

    Is It Possible to Create a Human Computer Program?

    Hello. I have been studying in my philosophy class a work by John Searle regarding whether it is possible to program a computer program (with hardware) to duplicate the functions of a human. I wrote up a six page paper against Searle and supported the prospect of a humans computer, but I do...
  16. R

    How Do You Calculate the Change in Focal Length for a Human Eye Lens?

    Homework Statement Suppose the lens in a human eye has far focal length equal to f0 = .0405 m, for distant objects to be in focus. (a) An object K is 1.72 m from the lens. How much should the focal length change to focus on the object K? (b) What is the magnification ( = image size divided...
  17. R

    Human Eye Optics - Answers Needed

    I reposted because I "bumped" this thread already with 2 replies and no one is answering.
  18. B

    Can EEG Readings Differentiate Between Human and Animal Brain Activity?

    Do humans have different EEG readings than animals?
  19. B

    Does the human belong to a kind of system?

    Does the human belong to a kind of system? Sometimes it feels like the world isn't natural. That all of our feelings and happenings really don't matter? And some things that seems logic are actually illusions of our mind? That the things that happens between friends and people has nothing to...
  20. G

    The Physics of A Human Landing and Rolling

    HI there, I'm a practicioner of Parkour, which is a discipline that involves training to allow yourself to pass any obstacles simply using your body. One of the movements which we use is a roll, designed to aid landing from height. As I understand it, the basic idea is that the roll...
  21. S

    The Impact of Vibration on Human Health

    gooooood evening.. i have presentation about the effect of vibration on human and i did not find what i want and i did not understant the topices when i searched from google .. so I will be grateful if anyone could help me..
  22. T

    How will the tragedy of the HIV epidemic effect human evolution?

    I believe I read the Black Death or Black Plague that effected Europe created a noticeable genetic bottlenecking in Europeans. HIV is still relatively new, but has anyone heard or have any ideas how HIV may effect human genetics and culture?
  23. S

    How long could human race survive without the sun?

    Hello, Here is my question: Just imagine the sun would stop shining, without exploding. It would just totally disappear without causing harm. How long would human race survive without the benefits of the sun? 10 minutes? 10 hours? 10 days? Could it stand the cold longer? How long would it...
  24. wolram

    Is Science Selfish? Exploring the Human Response to Theoretical Science

    Is, selfish, if it does not give some immediate or short term advantage no one gives it a thought, how many of the total population of Earth give a single thought to some grand unification theory?
  25. K

    Human Biology Help-Apologies for Vagueness

    I will try to follow the guidelines in the template but I may fall short as I copied and pasted this from another one of my threads on another forum. Apologies. I know I just joined but I'm in dire need of some homework help as I don't what to search on google and it's difficult to find...
  26. P

    Medical Exploring the Power of Human Minds

    is it true that human minds are connected by neurons or whatever? i heard that if u r thinking of something or someone, the other person thinks of the same thing?:approve:
  27. B

    What is the Relationship Between Focal Length and Distance in the Human Eye?

    Homework Statement Joe is hiking through the woods when he decides to stop and take in the view. He is particularly interested in three objects: a squirrel sitting on a rock next to him, a tree a few meters away, and a distant mountain. As Joe is taking in the view, he thinks back to what he...
  28. C

    Trivial pursuit and human extinction

    Trivial pursuit and human extinction I was awakened last night by a loud knocking on my door. Fortunately the knocking was not reality but was a dream. When I “heard” the knocking I sat upright in bed with my heart racing and immediately tried to determine if what I had heard was the...
  29. EnumaElish

    Weird question on abnormal human anatomy (hoping it not being the case)

    Over the long weekend I was touring a museum whence I glanced upon a thirtysomething woman and had to look again. There was a tiny arm coming out of her chest. I thought she must be carrying her tiny baby in a receiver (?) shawl wrapped around her, but did not inquire personally. I might have...
  30. S

    Exploring the Effects of Sirtuin Activators on Human Longevity

    Sirtuins are enzymes which repair telemeres that deteriorate to cause aging. They are normally released in response to stress such as calorie restriction or low insulin levels, but sir2 can be stimulated by certain chemicals. Why is it unfeasible to take molecules like resveratrol (found in red...
  31. Mk

    Do Human Eyes Grow? - Exploring the Cuteness Factor

    Do human eyes grow? I was thinking this might be a reason why people think big eyes are "cute," if babies were born with the same size eyes they have when they are old.
  32. N

    Are there things that are beyond the human brain

    The other day I was talking to my friend and we were just thinking about infinity. I used this analogy to prove how it is that we cannot 'see' some things. Lets take parrots, they can see ultraviolet I've read somewhere. But we cannot so we can't even imagine such a colour. It's beyond us. Such...
  33. baywax

    Altruism, Origins of Virtue: Human Instincts, Evolution of Cooperation

    Inspired by a book review of: The Origins of Virtue: Human Instincts and the Evolution of Cooperation by Matt Ridley Ridley suggests that altruism is instinctual. Cooperation and even self-sacrifice appear to Ridley to have evolved out of a need for and the instinct of survival of the species...
  34. C

    From Veggies to Meat: Man-Apes become Human

    From Veggies to Meat: Man-Apes become human The “man-apes” of Africa (australopithecines) was first discovered in a 1924 dig. This is considered by anthropologists as being one of the most exciting and enlightening finds of modern anthropology. The man-ape, which was first born perhaps a...
  35. D

    Can I Learn to Understand Human Action and Reaction?

    Hello! Anybody know any good pieces of work that will allow me to learn how to judge and react to another persons action or reaction to a particular event? Like how most human minds work in case scenario's and such. eh? Arigato, Chocobo
  36. B

    Medical How Does Your Brain Determine the Direction of Sound?

    How exactly does your mind tell you from where sound is coming from? If you hear something next to you, you can tell if it is on the right or left side. I can't understand how sound compression waves could tell.
  37. Loren Booda

    Altitude's effect on pitch of human voice

    Does the decrease in atmospheric pressure with increasing altitude affect frequency of sound, such as that of a mountaineer's voice?
  38. M

    How Fast do Human Feet Travel When Passing Each Other?

    Need some help. How fast are the human feet traveling as they pass each other while walking and running? Thanks.
  39. baywax

    Human Nature or Role Model Re-enactment?

    Is destructive behavior and benefiting psychologically as well as materially from other people's misfortune a part of human nature or an endless chain of role models that have been passed down from generation to generation to us today? Is our predisposition to compete (like in sports) and to...
  40. C

    Basic Human Rights+= Right to an independent original mind?

    Is this a valid thing for society to aim for? Would this do more harm than good? Technology is capable of taking us towards this.
  41. moe darklight

    Weird question: human ability to program DNA

    are we anywhere near understanding DNA well enough to "program" a new species. say, programing a cell to grow into an animal with specific traits. I know similar things are done to a certain extent with genetically modified foods and animals (or on mosquitoes and flies); I know we know enough...
  42. D

    Human Eye Structure: Investigating the Adaptive Function

    I've noticed that most animals have irises that fill the entire eye,but humans do not. Does anyone have an explanation for this? Does our sclera provide us something unique? What's the adaptive function one way or the other? This question has been bugging me for weeks. Thanks
  43. D

    How to calc human bicycle power in watts

    Homework Statement How to calculate Lance Armstrongs power output/calorie consumption at 30 mph, 125 miles on level ground , no wind, 157 lbs plus 16lb bike? Homework EquationsWhat equations do I use? The Attempt at a Solution I'm 14 years old, where do I start
  44. shintashi

    How fast does a human sink in h20?

    assuming a human being with average body type and health, how fast does a human being fall through water from the surface? what is the terminal velocity and what is it reached at? I've been trying to find answers everywhere but can't get a straight answer. These calculations would be useful...
  45. M

    Is taxonomy intrinsic or a human invention

    is taxonomy an intrinsic property of life, or a human way to look at it? I think, especially with asexual species, that it is really a human invention, not an actual property of life. However, certain things fit well. what do you think?
  46. L

    Experiment with high voltage that can show arcs / stun human

    I'm very interested in Experiment with high voltage that can show arcs. I also like to modify my swatter ( electric racket to kill mosquito/ flies), it is made in china. About the swatter: -It has only one diode at the secondary winding of the trafo, ithink this is for rectifying the ac...
  47. cronxeh

    Good Human Anatomy and Physiology textbooks

    Can anyone recommend a good textbook on A&P? I've seen a few on amazon but it did not quite have a feel to it. Also the Schaum's outline of Human A&P 2nd edition is over 10 years old This one https://www.amazon.com/dp/0805359095/?tag=pfamazon01-20 looks promising. Anyone have anything...
  48. baywax

    Ethics applies primarily to human situations

    The use of the word ethics applies primarily to human situations, actions and conditions. Ethics described: http://www.iep.utm.edu/e/ethics.htm Along with this explanation of the word ethics I wanted to explore whether the word also applied to mechanical systems. Can a mechanical system like...
  49. O

    Is population reduction the solution to environmental problems?

    Here is the full question: Reducing human population, disregarding the difficulty, would be the most effective way to: - reduce pollution (air, water, soil, noise...) and - avoid depleting natural resources (fish stocks, oil, forests...) and - prevent extinction of living species, as well as -...
  50. Loren Booda

    Exploring Human Muscle Movement: The Fastest Large-Scale Movements

    What is the fastest movement that larger scale human muscles (vs. cells) can make?
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