We all know pop singer Kei$ha can be a bit unusual at times.
Like when the "Gonna Die Young" singer admitted that she . (BTW, on her reality show Ke$ha: My Crazy, Beautiful Life, she said "it tasted kind of like candy" (does she have diabetes?).
So does it even raise an eyebrow when she says that someone stole her tail? Apparently Kei$ha volunteered, in an interview with , that:
"I had a tail when I was born. It was a tiny tail, about a quarter of an inch, then they chopped it off and stole my tail. That was when I was little. I'm really sad about that story."Is this even possible? Absolutely YES. <乌鸦传媒>Five Body Parts No Longer Needed
Human vestigiality involves those body parts that have lost all or most of their original function through evolution.
<乌鸦传媒>1. The Tail
A 5-6 week human embryo normally has an embryonic tail which contains 10 to 12 vertebrae. Because humans no longer need a tail to assist in balance or for mobility, over the next 2-3 weeks the cells in those tissues are signaled for cell death, or apoptosis, causing the tail to disappear by 8 weeks. The apoptosis is said to occur by inhibition of the .The coccyx is a remnant of this lost tail. The coccyx has probably not disappeared completely as it still serves a function as an anchor point for muscles of the spine and pelvis.
In a very small number of people the cells in the embryonic tail do not die and some portion of it may remain at birth. These are called "true tails" and arise from the most distal remnant of the embryonic tail. They can contain muscle, connective tissue, nerves, blood vessels and fatty tissue. They are covered with skin. They do not, however, include any vertebral bones, cartilage or spinal column. Tails are usually associated with .
True tails can vary in size from a fraction of an inch to several inches long. They can be removed surgically, usually shortly after birth.
About a third of what are reported as human tails are actually false or "pseudo tails." Although they have a superficial resemblance to true tails, they are usually complications of other processes such as, tumors (such as lipomas, teratomas and gliomas) or even the remnants of a.
The longest known "tail" was reportedly and belonged to a man named , who lives in West Bengal, India. It is not believed to be a true tail, however, but rather a case of spina bifida.
<乌鸦传媒>2. The Appendix
The function of the appendix is unknown although there are several proposed theories. One is that the appendix is purely vestigial -- that our distant ancestors used a larger version of it to store bacteria that help digest complex plants. Others say that the appendix has an immune system function, housing infection-fighting cells. Still others say that it acts as a storage center for helpful bacteria to maintain our
The main problem associated with the appendix is, of course, the infection
Removal of the appendix does not seem to cause any harm to a person’s health. In the past, the appendix was routinely removed and discarded during other abdominal surgeries as a preventive measure of later contracting appendicitis. However, new surgical procedures have been able to use the appendix as a replacement for a diseased ureter or urinary sphincter muscle, so healthy appendices are now left in place. <乌鸦传媒>3. Male Nipples If the function of a nipple is to allow a baby to suckle milk, then why do men (and for that matter nearly all male mammals) have nipples?
The bottom line answer -- because women do.
All fetuses initially develop under the influence of the female hormone estrogen. This causes the embryos to develop parallel mammary ridges (called milk lines) by 3-4 weeks gestation. These will later develop into nipples.
At about 6-8 weeks, cells in male infants begin to differentiate into Leydig cells and begin to produce the male hormone testosterone. From this point on, development of male traits increases, and the further development of female structures is inhibited.From an evolutionary standpoint, , from Carleton University, puts it this way:
"The uncoupling of male and female traits occurs if there is selection for it: if the trait is important to the reproductive success of both males and females but the best or "optimal" trait is different for a male and a female. We would not expect such an uncoupling if the attribute is important in both sexes and the "optimal" value is similar in both sexes, nor would we expect uncoupling to evolve if the attribute is important to one sex but unimportant in the other. The latter is the case for nipples. Their advantage in females, in terms of reproductive success, is clear. But because the genetic "default" is for males and females to share characters, the presence of nipples in males is probably best explained as a genetic correlation that persists through lack of selection against them, rather than selection for them. "<乌鸦传媒>4. Wisdom Teeth
Wisdom teeth, or third molars, are the last teeth to develop and appear in your mouth. They come in between the ages of 17 and 25, and are the ones in the back of the mouth closest to the soft palate.
Our prehistoric ancestors had much larger and prominent jaws because their teeth played a vital role in survival. Their diet consisted of tough, chewy leaves and roots and raw meat, and having 32 teeth helped break down these foods.
As early human's stance became more upright, they were able to use their hands to gather food, and began to create the first tools. This, plus the use of fire to cook food allowed our ancestor's diet to change dramatically.
At the same time, the human brain was growing. The skull changed shaped to accommodate this, with a bigger cranium and smalerl jaw. Having a smaller jaw leads to crowding of the teeth- especially of those third molars.
This can lead to several problems:
- Impaction: An impacted wisdom tooth has failed to erupt through the gum line.They may also come in at a funny angle or in an unexpected location. Poor positioning can cause pain and infection.
- The third molars are difficult to clean, so they could rot and infect nearby teeth.
- They may also crowd adjacent teeth, undoing years of braces.
Goose bumps -- also called goose flesh or goose pimples, or the medical term cutis anserina -- are the bumps on a person's skin at the base of body hairs that may develop involuntarily when a person is cold or experiences strong emotions such as fear, nostalgia, pleasure, euphoria, awe, admiration, and sexual arousal.
The formation of goose bumps in humans under stress is a vestigial reflex; a possible function in human evolutionary ancestors was to raise the body's hair, making the ancestor appear larger and scaring off predators. Raising the hair is also used to trap an extra layer of air, keeping an animal warm.
Of course, with our marked decrease in body hair, goose bumps don't do much for us these days. Either in scaring off predators or keeping us warm.
Here's an about how music, particularly sad music and emotionally painful memories give some people goosebumps.