5 Things we Don't know the Facts About.

          5 Things we Don't know the Facts About.

1. Where did Dog Come From?:

 They’re some of our most constant companions, but there’s a lot we don’t know about when dogs were first domesticated, where the process happened, and what the first domesticated dogs even were
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Studies on the subject have proven highly inconclusive, with estimates for the first domestication ranging from 9,000–34,000 years ago. Not only is that a huge gap, but it leaves a lot of unanswered questions as to how it happened. Dogs on the most distant end of that scale would have been associating with hunter-gatherer groups, while the more recent instances of domestication would have been happening when the human race had already discovered agriculture and settled into a more sedentary lifestyle.
Researchers from the University of Turku have isolated DNA from some of man’s early canine companions with some staggering implications. Some of the oldest DNA samples were taken from dogs that were living alongside humans around 33,000 years ago and were traced through to dogs that lived in Greenland about 1,000 years ago. But this particular DNA seems to be unrelated to today’s dogs, and it’s now suggested that some of the “dogs” that were domesticated for thousands of years weren’t the same as today’s dogs and were instead a sort of sister species. Ancient dogs have been found in Europe, the Middle East, and Asia, but it’s still not known if the idea of domestication spread from one area to the other or occurred independently in all areas. If it did, it’s not known who was first.

2.Is Virus A Living?: 

  For the most part, everything falls into one of two categories: It’s either alive, or it isn’t. Ever since scientists have been aware of the existence of viruses, they’ve been unable to successfully determine which of these two very distinct groups viruses belong to. Originally, viruses were thought to be alive. The scientists that discovered viruses saw them as organisms that could spread and multiply, suggesting that they were very clearly alive. By the 1930s, however, researchers from the Rockefeller University were finally able to get a look into what was going on inside a virus. Since it didn’t have any metabolic functions, they decided that it wasn’t alive.
But it’s far from clear, as further research by the same team discovered that a virus also exhibits one of the key components of life: reproduction. It not only makes more of itself but creates more proteins and internal chemical structures. Viruses have also been known to change over time, evolve, and carry on processes like repairing damage done to them. All this seems to indicate they’re alive, unless nonliving organisms are also capable of evolution, which seems like a pretty odd thing to even suggest.
Viruses are also unable to carry on these processes outside of a living host, leading some to suggest that they’re functioning on something along the lines of life borrowed from another organism—but that doesn’t make the answer any more clear.

3.Why Do We Sleep?:

   While we do know that the human body is regulated by a circadian clock that keeps humans on a sleep/wake cycle, we don’t really know why. Sleep is the time when our bodies repair tissues and perform other maintenance activities, and we spend nearly a third of our lives snoozing. Some other organisms don’t need to sleep at all, so why do we? There are a few different ideas out there, but none seem to solidly answer the question. Some theorize that animals who are able to sleep have evolved the ability to hide from predators, while others who need to remain more alert are able to rest and regenerate in other ways without fully going to sleep. While scientists don’t quite know why we do it, they are starting to learn more about why it is important, and how sleep impacts important things like brain plasticity.

4.How and Where Does Hunger  Come?:

Hunger has been a question since man had a craving for food. What makes me hungry? what is this feeling I am getting? In early years, scientists thought that hunger resulted from the stomach being empty. To prove his hypothesis one scientist even did the unthinkable and swallowed a deflated balloon. Upon reaching the stomach, he inflated the balloon. When pressure recording were taken it was shown that the stomach contracts when empty. It was found that these muscle contraction cause some food cravings and because of this scientist’s believed that this was the cause of hunger, and an empty stomach.
Further experiments were done including one where a stomach was completely removed and the results yielded that the contraction of the stomach was not the cause of hunger. After all how can a person still be hungry when there is no stomach to contract! It was found that the hypothalamus, or a section in the brain classified as the main control center, was found to be the main cause of hunger.

 As most people know, when your hungry you have an appetite.
If you have just eaten or do not crave any food this stage is called satiety because the nutrients that the body lacked has been replinished.
Lastly, anorexia is when the physiologic state of hunger is present without the desire to eat. This basically means that all though the body is asking for food, the person is ignoring its appetite basically starving themselves.
It is through these three states in which scientists are studying to figure out what makes the human body hungry.

5.Why Do We Age and At Different Rates?:

  Every day we deal with the problems of aging, ever so gradually. We’ve been doing it for as long as we’ve been a species, but we have no idea what actually causes it. We know what happens to cells as they age: Muscles lose mass, tissues become more or less rigid, connective tissues stiffen, and new cells become less and less efficient at absorbing nutrients and removing waste. We just don’t know why.
There are a couple of different theories on why cells age the way they do, including the idea that the aging process is a by-product of the body’s waste materials, or that it’s because of damage done by external factors like ultraviolet rays. It’s also been suggested that we’re simply genetically programmed to age, and how fast or how well we age has nothing to do with external factors.
Even more bizarre is the question of why we age at different rates. Looking at the methylation patterns of cells gives an indication of how old they are, and all of our cells age at different rates. Female breast tissue, for example, shows patterns and changes that indicate it’s about three years older than a person’s calendar age. At the other end of the spectrum are heart cells, which age more slowly and can actually test as being several years younger than the body as a whole. Just why the body ages as it does—and why it ages at all—is nowhere near being completely understood.