Erica Liu

(all completed)

Wiki Post #3 Dynamic Equalibrium
January 24, 2013
Qi and Homeostasis

China is a country with long history. Long before western medical theory was built up, Chinese have developed their own concept on health. In a traditional Chinese view, all creatures have Qi, and good health is a balance of Yin Qi and Yang Qi.

But, what is Qi ?

Qi, pronounced "chee". You may see it spelled "Chi" or even "Ki" in Japanese, but they all carry the same meaning.
Most people in the West, including many authors, think qi means energy, but this represents a basic misconception that is not supported by Chinese ancient sources. This common mistranslation has lead to many erroneous ideas and understandings with regards to Chinese medicine. The term qi is complex, multilayered, and at its core, profound. It is one of the most difficult terms in Chinese language to translate.

Qi can be viewed as a concept used to describe the numerous types of manifestations, functions, and transformations of the human body and the larger universe.
The Chinese see qì as something that not only creates form but also powers function. Stated another way, we can say that with regards to the human body, qi represents the functional and transformative aspect of human physiology. According to Chinese medical theory, the basic functional aspects of qi are as follows:

Qi Transforms – It transforms foods and fluids into usable material and waste.
Qi Transports – It transports usable materials around the body and waste out of the body.
Qi Holds – It holds blood in the vessels and other fluids in the body. (Spider veins, varicose veins, urinary incontinence, and spontaneous sweats are signs of insufficient qi.)
Qi Raises – It holds the organs in place. (A prolapsed organ such as hemorrhoids or uterine prolapse is a sign of insufficient qi.)
Qi Protects – Think of the function of the immune system. (Poor immunity is a sign of insufficient qi.)
Qi Warms – It keeps the body warm.

In Western medical terminology, all of these functions come together to create homeostasis, which is the property of a system that regulates its internal environment and maintains a stable, constant condition. The basic functions of qi are nothing more than an expression of all these functions. Therefore, when Chinese medicine talks about regulating the qi in order to achieve a state of balance, it is simply referring to applying different methods such as herbal medicine and acupuncture to help the body self-regulate in order to achieve optimal homeostasis.

Herbal Medicine
Chinese herbs work to maintain the state of ‘homeostasis’ or stability in a human body.
Traditional Chinese herbal medicine draws on ancient practices. Direct experience taught them which plants were toxic, which ones imparted strength and sustained life, and which had special healing qualities. Diagnosis in traditional Chinese medicine is simple yet effective -- diagnostic observation includes looking, listening, smelling, asking, and touching. Many factors are considered in determining a cause of illness with traditional Chinese medicine, including dietary habits and emotions.The herbs and the recomendation the doctor gave out usually can help the body self-regulate and stay in health.
traditional-chinese-medicine-1.jpgGinger root is often used in traditional Chinese medicine to treat symptoms of indigestion, the common cold, and other ailments.


Physiologically, Qi flows throughout the body 24 hours per day, maintaining a balance of Yin and Yang. When the flow of Qi is interrupted by any pathological factor the balance of Yin and Yang will be lost and consequently dis-ease may occur. Physiologically, Qi flows throughout the body 24 hours per day, maintaining a balance of Yin and Yang. When the flow of Qi is interrupted by any pathological factor the balance of Yin and Yang will be lost and consequently dis-ease may occur. The diagram below explains Yin and Yang.
Within Chinese Cosmology, all of creation is born from the marriage of two polar priciples, Yin and Yang
It’s simply a concept of balancing everything to maintain homeostasis.

Pain is interpreted as the blockage of Qi flow (or no free flow of Qi). Acupuncture stimulation resolves this blockage, freeing the flow of Qi and enabling the body to heal itself. Homeostasis is restored when Yin and Yang Qi are in balance.

Modern research shows that acupoints are located in the areas where there is a high density of free nerve endings, mast cells, small arterioles, and lymphatic vessels. Most acupoints are motor points. A great number of studies indicate that stimulation of acupoints induce release of beta-endorphin, serotonin, and other neurotransmitters. Therefore, acupuncture for pain relief is well supported by these scientific studies. As more studies are conducted, the mechanism of this ancient therapy will be better understood.

Acupoints may be stimulated in a variety of ways. These techniques include dry needling, moxibustion, aquapunctue and electro-stimulation. Whatever tools are used, the goal is always the same: to restore the flow of Qi and allow homeostasis to return.

zjj.jpgThis is a scene of acupuncture, solid needles have been inserted into acupuncture points in the skin.

Tai Chi Chuan and Qi Gong

Another way that Chinese created to maintain the balance of Yin and Yang is to do the exercise Tai Chi Chuan and Qi Gong( Chi Kung). They are two similar exercise in the view of Qi. In China a vast amount of research has been carried out into the effects of tai chi and chi kung on various physical and mental conditions. The results vary from good to quite extraordinary in many instances. The effects found on the human body that are due to tai chi practice are on most body systems. The exercise also help metabolism.

You will know more about Tai Chi and try to do the healthy exercise Tai Chi by watching the video below

Further reading
This essay explains Qi very well.
Find out how Chinese medicine works here.
This is how Tai Chi affects the body systems.

This site gives more further information about acupuncture.


Wiki Post #2 Evolution
January 14, 2013
Genectic Drift

Genetic drift—along with natural selection, mutation, and migration—is one of the basic mechanisms of evolution.

In each generation, some individuals may, just by chance, leave behind a few more descendents and genes, than other individuals. The genes of the next generation will be the genes of the “lucky” individuals, not necessarily the healthier or “better” individuals. That, in a nutshell, is genetic drift. It happens to ALL populations—there’s no avoiding the vagaries of chance.


This cartoon shows genetic drift is an entirely random process. The chance of the bettles being stepped and killed has nothing to do with their colour.
So although genetic drift is a mechanism of evolution, it doesn’t work to produce adaptations.

Founder Effect
The founder effect is the reduction in genetic variation that results when a small subset of a large population is used to establish a new colony. The new population may be very different from the original population, both in terms of its genotypes and phenotypes. In some cases, the founder effect plays a role in the emergence of new species.
A founder effect occurs when a new colony is started by a few members of the original population. This small population size means that the colony may have:
reduced genetic variation from the original population.
a non-random sample of the genes in the original population.

For example, the Afrikaner population of Dutch settlers in South Africa is descended mainly from a few colonists. Today, the Afrikaner population has an unusually high frequency of the gene that causes Huntington’s disease, because those original Dutch colonists just happened to carry that gene with unusually high frequency. This effect is easy to recognize in genetic diseases, but of course, the frequencies of all sorts of genes are affected by founder events.

Bottleneck Effect
Population bottlenecks occur a population’s size is reduced for at least one generation. Because genetic drift acts more quickly to reduce genetic variation in small populations, undergoing a bottleneck can reduce a population’s genetic variation by a lot, even if the bottleneck doesn’t last for very many generations. This is illustrated by the bags of marbles shown below, where, in generation 2, an unusually small draw creates a bottleneck.


A bottlenecking event could be an epidemic or natural disaster like fire or flood. It is hypothesized that the lack of genetic diversity among African cheetahs is due to some bottlenecking event in the species' past.

Loss of genetic variation is a result of a population bottleneck. Reduced genetic variation means that the population may not be able to adapt to new selection pressures, such as climatic change or a shift in available resources, because the genetic variation that selection would act on may have already drifted out of the population
An example of a bottleneck:
Northern elephant seals have reduced genetic variation probably because of a population bottleneck humans inflicted on them in the 1890s. Hunting reduced their population size to as few as 20 individuals at the end of the 19th century. Their population has since rebounded to over 30,000—but their genes still carry the marks of this bottleneck: they have much less genetic variation than a population of southern elephant seals that was not so intensely hunted.

Effects of Genetic Drift
The main effect of genetic drift is that it can cause populations to lose genetic variation, especially for small populations.

Imagine that our random draws from the marble bag produced the following pattern: 5:5, 6:4, 7:3, 4:6, 8:2, 10:0, 10:0, 10:0, 10:0, 10:0... Why did we keep drawing 10:0? Because if the green marbles fail to be represented in just one draw, we can’t get them back—we are “stuck” with only brown marbles. The cartoon below illustrates this process, beginning with the fourth draw.
The same thing can happen to populations. If the gene for green coloration drifts out of the population, the gene is gone for good—unless, of course, a mutation or gene flow reintroduces the green gene.

And with less genetic variation, there is less for natural selection to work with. If the green gene drifts out of the population, and the population ends up in a situation where it would be advantageous to be green, the population is out of luck. Selection cannot increase the frequency of the green gene, because it’s not there for selection to act on. Selection can only act on what variation is already in a population; it cannot create variation.

The video below is going to show the effect of genectic drift and simulate how founder effect and bottleneck effect works.

Further reading:
The site gives further explaination on genetic drift.
This is a flash simulation on genetic drift.
This article gives out many examples for genetic drift.
This site explains founder effect in details.


Wiki Post #1 Genetics
December 21, 2012

Colour Blindness

Colour blindness is a common genetic disorder.It affects about five to eight percent of males (approximately 10.5 million) and less than one percent of females. There are two major types of color blindness: those who have difficulty between red and green, and those who have difficulty distinguishing between blue and yellow.

Colour blindness is a condition where the eyes have trouble distinguishing certain colours. The most common type is red-green color-blindness, where red and green are seen as the same color.

Rainbow in their eyes is not colourful as normal people see.


This is the traffic light in the eyes of red-green colour-blind people. The good news is most people have mild forms of colour blindness that don't interfere much with their daily lives.

Colour Blindness Test

Colour blindness can be found out by simple test.Here is a sample of charts used to test for color-blindness. There is a number in the center of the circle. If you can see the number, chances are you are not color-blind.

Plate 1
Those with normal color vision should read the number 74.

Plate 2
Those with normal color vision should read the number 6.

Plate 3
Those with normal color vision should read the number 29.
Those with red-green deficiencies read the number 70.
Those with total color-blindness can not read any number.

Plate 4
Those with normal color vision should not be able to read any number.
Most of those with red-green deficiencies should read the number 5.
Those with total color -blindness can not read any number.

Cause of Colour Blindness

The area at the back of the eye, called the retina, is sensitive to light and colour. It contains specialized cells, called cones, which respond to colour. There are three types
of cone cells. One responds best to red light, one to green light, and one to blue light. When a specific type of cone cell doesn't work properly, a person will have trouble seeing the colour that particular cone cell responds to. For example, a person with red colour blindness has a defect in red cone cells.


Most colour blindness is inherited, although some cases are caused by an injury or disease of the retina or optic nerve, the nerve that takes information from the eye to the brain. People inherit colour blindness as a result of a defect on the gene(s) for colour located on the X chromosome.

Men inherit colour blindness 10 times as often as women do. Colour blindness "shows up" in men because they have only one X chromosome. Since women inherit two X chromosomes, a healthy gene on one X chromosome can override the unhealthy gene on the other. A woman can still have the unhealthy gene; it just doesn't always show up. She can, however, pass the gene to her children. A person who doesn't have a genetic condition like colour blindness but who can pass it to her children is called a "carrier."


The veodeo below provides more details about colour blindness and the genetic facts behind it.

Further Reading:
This site explain colour blindness as a sex-linked condition. They have many stastistic.
Here are some facts about colour blindness.
This is a general introduction of colour blindness. It includes facts and explaination.
This is about how people live with colour blindness.