I shall now continue on my last post.
The Birth Control Pills or Pregnancy Pills that was mentioned in the earlier post are known as daily contraceptive pills that are taken daily to prevent pregnancy. There is another type of pill that is used for emergency contraception.
These pills are commonly named as the "Morning After Pills". Pregnancy can be prevented after sexual intercourse by taking Emergency Contraceptive pills (EC). It works by giving the body a short, high, burst of synthetic hormones. This disrupts hormone patterns needed for pregnancy. EC affects the ovaries and the development of the uterine lining, making pregnancy less likely. Depending upon where the woman is in her menstrual cycle, the EC hormones prevent pregnancy in different ways. It prevents ovulation, which is the process of the egg leaving the ovary and moving into the fallopian tube. It blocks the hormones needed for the egg to be able to be fertilized. It affects the lining of the uterus and alters sperm transport which prevents sperm from meeting the egg and fertilizing it.
EC may be effective up to 120 hours, which is about 5 days after intercourse. But, it is most effective within the first 24 hours. Emergency Contraception reduces the risk of pregnancy by 75%. However, EC does not protect against reproductive tract infections, including HIV/AIDS.
The advantages of using Emergency Contraception Pills are:
- They can be used after intercourse.
-Easy to use.
-Does not affect future fertility.
However, the disadvantages are as follows:
-Does not protect against Sexually Transmitted Infections, including HIV/AIDS.
-Most effective when taken as soon as possible after unprotected vaginal intercourse.
-Side effects may include nausea.
-Must be readily available.
I shall continue on my next post.
Sources:
http://www.fwhc.org/birth-control/ecinfo.htm
Glossary:
Synthetic: Noting or pertaining to compounds formed through a chemical process by human agency, as opposed to those of natural origin: synthetic vitamins; synthetic fiber.
Contraception: The deliberate prevention of conception or impregnation by any of various drugs, techniques, or devices; birth control.
Saturday, July 19, 2008
Saturday, July 12, 2008
Entry 9: 13/7/08
I will now start on my second topic, which is Issues on Sex. My first question is: How do pregnancy pills work, and does consuming pregnancy pills have any side effects?
Pregnancy pills, or Birth Control Pills(BCPs) are daily pills that contain hormones to change the way the body works and prevent pregnancy. Hormones are chemical substances that control the functioning of the body's organs. In this case, the hormones in the Pill control the ovaries and the uterus. Most birth control pills are "combination pills" containing a combination of the hormones estrogen and progesterone, which prevent ovulation (the release of an egg during the monthly cycle). A woman cannot get pregnant if she doesn't ovulate because there is no egg to be fertilised. The Pill also works by thickening the mucus around the cervix, which makes it difficult for sperm to enter the uterus and reach any eggs that may have been released. The hormones in the Pill can also sometimes affect the lining of the uterus, making it difficult for an egg to attach to the wall of the uterus.
Another kind of pill change the number of monthly periods. It is the low-dose progesterone pill, sometimes called the mini-pill. This type of birth control pill differs from the other pills in that it only contains one type of hormone — progesterone — rather than a combination of estrogen and progesterone. It works by changing the cervical mucus and the lining of the uterus, and sometimes by affecting ovulation as well. The mini-pill can be slightly less effective at preventing pregnancy.
I shall continue in my next post.
Sources:
http://kidshealth.org/teen/sexual_health/contraception/contraception_birth.html
Glossary:
Progesterone: A steroid hormone, C21H30O2, secreted by the corpus luteum of the ovary and by the placenta, that acts to prepare the uterus for implantation of the fertilized ovum, to maintain pregnancy, and to promote development of the mammary glands.
Estrogen: Any of several steroid hormones produced chiefly by the ovaries and responsible for promoting estrus and the development and maintenance of female secondary sex characteristics.
Pregnancy pills, or Birth Control Pills(BCPs) are daily pills that contain hormones to change the way the body works and prevent pregnancy. Hormones are chemical substances that control the functioning of the body's organs. In this case, the hormones in the Pill control the ovaries and the uterus. Most birth control pills are "combination pills" containing a combination of the hormones estrogen and progesterone, which prevent ovulation (the release of an egg during the monthly cycle). A woman cannot get pregnant if she doesn't ovulate because there is no egg to be fertilised. The Pill also works by thickening the mucus around the cervix, which makes it difficult for sperm to enter the uterus and reach any eggs that may have been released. The hormones in the Pill can also sometimes affect the lining of the uterus, making it difficult for an egg to attach to the wall of the uterus.
Another kind of pill change the number of monthly periods. It is the low-dose progesterone pill, sometimes called the mini-pill. This type of birth control pill differs from the other pills in that it only contains one type of hormone — progesterone — rather than a combination of estrogen and progesterone. It works by changing the cervical mucus and the lining of the uterus, and sometimes by affecting ovulation as well. The mini-pill can be slightly less effective at preventing pregnancy.
I shall continue in my next post.
Sources:
http://kidshealth.org/teen/sexual_health/contraception/contraception_birth.html
Glossary:
Progesterone: A steroid hormone, C21H30O2, secreted by the corpus luteum of the ovary and by the placenta, that acts to prepare the uterus for implantation of the fertilized ovum, to maintain pregnancy, and to promote development of the mammary glands.
Estrogen: Any of several steroid hormones produced chiefly by the ovaries and responsible for promoting estrus and the development and maintenance of female secondary sex characteristics.
Entry 8: 13/7/08
To conclude, bees are very important to the ecosystem. They have a very big role in their habitat, not unlike many other organisms. Bees are major pollinators for many flowering plants. If they were no bees, many species of flowering plants may decrease in number or even go extinct. Also, bees provide food for many species of animals, including us. Honey that is made by the bees are food for us, bears, badgers and other mammals. Also, bees are preyed upon by other insects such as praying mantises or dragonflies. If the bees were extinct, these insects would decrease in population as bees are a source of food for them. Also, the bees are important to us, as farming of certain fruits depend on these insects for pollination. If the bees were extinct, we would have certainly have lesser food to eat, and millions of people would starve.
So we can see how the bees affects the ecosystem in many ways, in its roles as prey and pollinator. If bees would die out, it would cause a chain effect in its habitat, and many organisms would be soon extinct as well.
So we can see how the bees affects the ecosystem in many ways, in its roles as prey and pollinator. If bees would die out, it would cause a chain effect in its habitat, and many organisms would be soon extinct as well.
Wednesday, July 9, 2008
Entry 7: 9/7/08
I shall continue on my last post.
In the June 28 issue of the Straits Times, the Straits Times reported that bees in Europe and the United States of America. According to the article, bees are not just important for the production of honey. Three-quarters of flowering plants rely on the bees and other pollinators such as birds to help them reproduce. Bee pollination alone is responsible for US$15 billion annually in crop value in the United States alone. Bees are even more important to farmers who grow almonds, citrus fruits, apples, pears and cucumbers, because the plants do not self-pollinate.
However, bee numbers are declining fast in the US and Europe. In 2006, US beekeepers reported losing 30% to 90% of their hives. This phenomenon because known as Colony Collapse Disorder. Congressman Dennis Cardoza of California revealed that without bees, there is no way for US farmers to continue growing high-quality and nutritious food that the US relies on. This was a problem they cannot ignore.
The cause of the disorder remains unknown, although the collapse of hives has been linked with Pesticides, viruses, parasites and even cellphone interference with bee navigation.
Einstein once said that without bees, the world would starve in four years. Without bees, there would be no production of honey and no external pollination of crops and stock-feed. This would undoubtedly cripple the world's economy, and cause major food shortages. This is because the bees act as important pollinators which help flowering plants to reproduce. Many of these plants can be fruits, berries or nuts, which would not grow without the bees' help. With lesser food, more people would have to go hungry. Also, animals such as bears would decrease in their numbers, which can cause their prey to overpopulate and cause an imbalance in the ecosystem. Also, predators that hunt bees might also decrease in number.
Hence, we can conclude how important bees are, regardless towards man or animals.
Sources:
The Strait Times (World)
Issue 28/6/08
Article: Where have all the bees gone?
Glossary:
Stock-feed: Plant material that is fed to livestock.
In the June 28 issue of the Straits Times, the Straits Times reported that bees in Europe and the United States of America. According to the article, bees are not just important for the production of honey. Three-quarters of flowering plants rely on the bees and other pollinators such as birds to help them reproduce. Bee pollination alone is responsible for US$15 billion annually in crop value in the United States alone. Bees are even more important to farmers who grow almonds, citrus fruits, apples, pears and cucumbers, because the plants do not self-pollinate.
However, bee numbers are declining fast in the US and Europe. In 2006, US beekeepers reported losing 30% to 90% of their hives. This phenomenon because known as Colony Collapse Disorder. Congressman Dennis Cardoza of California revealed that without bees, there is no way for US farmers to continue growing high-quality and nutritious food that the US relies on. This was a problem they cannot ignore.
The cause of the disorder remains unknown, although the collapse of hives has been linked with Pesticides, viruses, parasites and even cellphone interference with bee navigation.
Einstein once said that without bees, the world would starve in four years. Without bees, there would be no production of honey and no external pollination of crops and stock-feed. This would undoubtedly cripple the world's economy, and cause major food shortages. This is because the bees act as important pollinators which help flowering plants to reproduce. Many of these plants can be fruits, berries or nuts, which would not grow without the bees' help. With lesser food, more people would have to go hungry. Also, animals such as bears would decrease in their numbers, which can cause their prey to overpopulate and cause an imbalance in the ecosystem. Also, predators that hunt bees might also decrease in number.
Hence, we can conclude how important bees are, regardless towards man or animals.
Sources:
The Strait Times (World)
Issue 28/6/08
Article: Where have all the bees gone?
Glossary:
Stock-feed: Plant material that is fed to livestock.
Sunday, July 6, 2008
Entry 6: 6/7/08
I shall now continue on my last post.
The seeds of many vegetables depend on the honey bee. The value of crops that rely on the bee has been estimated to be as high as ten billion dollars annually in the United States. The queen (head bumble bee) hibernates during the winter season and begins a new colony in the spring. Bee scientists have developed a way for the queens to skip their hibernation and produce colonies all year. Colonies of bumble bees are used extensively in greenhouse pollination of crops such as strawberries and tomatoes.
Bees do have many predators even though it may not seem so. Animals such as bears and Argentine ants may destroy a hive in search of honey. By eating the wax in a honeycomb of a weak colony, the wax moth may also destroy the hive. Animals prey upon individual honey bees which sometimes may weaken colonies, reducing the number of bees in the hive. Honey bees often fall prey to parasites and diseases. Two widespread contagious bacterial diseases called American and European foulbrood attack the bee larvae, hence reducing the number of larvae that will grow to become worker bees. Nosema, a protozoan parasite and virus, can cause dysentery and paralysis in adult bees. Mites, also called honey bee mites, have destroyed thousands of hives in Asia, Europe, and North and South America. Thousands of bees are killed each year by insecticides meant to kill other insects. Weed sprays destroy an important source of food for the bees by killing weeds and their flowers.
If the bees began to disappear, we would have to rely more on other insects and mammals to spread the pollen of flowers in order for pollination. The pollination process of the flowers would begin to slow down and eventually some species of wild flowers would begin to become extinct. The flowers would not be the only ones affected. Many animals would also suffer from a loss of food, as the fruits produced from the flowers would decrease or disappear. Herbivores that feed on these fruits could die out. Then, carnivores such as pumas or bears could also be affected as these herbivores begin to decrease in numbers.
I shall continue on my next post...
Sources:
http://www.amnh.org/nationalcenter/youngnaturalistawards/1998/bees.html
Glossary:
Dysentery: An inflammatory disorder of the lower intestinal tract, usually caused by a bacterial, parasitic, or protozoan infection and resulting in pain, fever, and severe diarrhea, often accompanied by the passage of blood and mucus.
Protozoan: Any of a diverse group of eukaryotes, of the kingdom Protista, that are primarily unicellular, existing singly or aggregating into colonies, are usually nonphotosynthetic, and are often classified further into phyla according to their capacity for and means of motility, as by pseudopods, flagella, or cilia.
The seeds of many vegetables depend on the honey bee. The value of crops that rely on the bee has been estimated to be as high as ten billion dollars annually in the United States. The queen (head bumble bee) hibernates during the winter season and begins a new colony in the spring. Bee scientists have developed a way for the queens to skip their hibernation and produce colonies all year. Colonies of bumble bees are used extensively in greenhouse pollination of crops such as strawberries and tomatoes.
Bees do have many predators even though it may not seem so. Animals such as bears and Argentine ants may destroy a hive in search of honey. By eating the wax in a honeycomb of a weak colony, the wax moth may also destroy the hive. Animals prey upon individual honey bees which sometimes may weaken colonies, reducing the number of bees in the hive. Honey bees often fall prey to parasites and diseases. Two widespread contagious bacterial diseases called American and European foulbrood attack the bee larvae, hence reducing the number of larvae that will grow to become worker bees. Nosema, a protozoan parasite and virus, can cause dysentery and paralysis in adult bees. Mites, also called honey bee mites, have destroyed thousands of hives in Asia, Europe, and North and South America. Thousands of bees are killed each year by insecticides meant to kill other insects. Weed sprays destroy an important source of food for the bees by killing weeds and their flowers.
If the bees began to disappear, we would have to rely more on other insects and mammals to spread the pollen of flowers in order for pollination. The pollination process of the flowers would begin to slow down and eventually some species of wild flowers would begin to become extinct. The flowers would not be the only ones affected. Many animals would also suffer from a loss of food, as the fruits produced from the flowers would decrease or disappear. Herbivores that feed on these fruits could die out. Then, carnivores such as pumas or bears could also be affected as these herbivores begin to decrease in numbers.
I shall continue on my next post...
Sources:
http://www.amnh.org/nationalcenter/youngnaturalistawards/1998/bees.html
Glossary:
Dysentery: An inflammatory disorder of the lower intestinal tract, usually caused by a bacterial, parasitic, or protozoan infection and resulting in pain, fever, and severe diarrhea, often accompanied by the passage of blood and mucus.
Protozoan: Any of a diverse group of eukaryotes, of the kingdom Protista, that are primarily unicellular, existing singly or aggregating into colonies, are usually nonphotosynthetic, and are often classified further into phyla according to their capacity for and means of motility, as by pseudopods, flagella, or cilia.
Entry 5: 6/7/08
I will now post my second question on the topic Ecology and Nutrient Cycles in the Ecosystem which is as follows: What would happen if bees were extinct?
Bees are an excellent example of symbiosis known as mutualism. Mutualism is the association between unlike organisms which both parties benefit from. Bees cannot survive without flowers and the flowers' existence depends on the bees. For the bees, the pollen and nectar from many flowers is an important source of fats, proteins, vitamins, and minerals. The nectar is a source of energy. Bees gradually switched from eating other insects to flowers as their source of food. With the passage of time, bees have become completely dependent on flowers as a food source. The flowers also stand to gain from this unusual partnership. When the bees travel from one flower to another to collect nectar, pollen clings onto them. The pollen is then transferred to another flower of the same species as the bees visit more flowers. This fertilises or pollinates the flower. The plants can then produce their own fruit and reproduce using the bees.
Because of this partnership, flowers can bear fruit and bees can make honey. both honey and fruits are an important part of our diet, and are sources of food for many other specis of animals.
There are many kinds of fruit crops that rely on the honey bee for its role in pollination. This large group includes almonds, apples, apricots, avocados, blackberries, cantaloupes, cherries, cranberries, cucumbers, pears, raspberries, strawberries, and watermelons.
I shall continue in my next post in a while...
Sources:
http://www.amnh.org/nationalcenter/youngnaturalistawards/1998/bees.html
Glossary:
Pollination: The process by which plant pollen is transferred from the male reproductive organs to the female reproductive organs to form seeds. In flowering plants, pollen is transferred from the anther to the stigma, often by the wind or by insects. In cone-bearing plants, male cones release pollen that is usually borne by the wind to the ovules of female cones.
Bees are an excellent example of symbiosis known as mutualism. Mutualism is the association between unlike organisms which both parties benefit from. Bees cannot survive without flowers and the flowers' existence depends on the bees. For the bees, the pollen and nectar from many flowers is an important source of fats, proteins, vitamins, and minerals. The nectar is a source of energy. Bees gradually switched from eating other insects to flowers as their source of food. With the passage of time, bees have become completely dependent on flowers as a food source. The flowers also stand to gain from this unusual partnership. When the bees travel from one flower to another to collect nectar, pollen clings onto them. The pollen is then transferred to another flower of the same species as the bees visit more flowers. This fertilises or pollinates the flower. The plants can then produce their own fruit and reproduce using the bees.
Because of this partnership, flowers can bear fruit and bees can make honey. both honey and fruits are an important part of our diet, and are sources of food for many other specis of animals.
There are many kinds of fruit crops that rely on the honey bee for its role in pollination. This large group includes almonds, apples, apricots, avocados, blackberries, cantaloupes, cherries, cranberries, cucumbers, pears, raspberries, strawberries, and watermelons.
I shall continue in my next post in a while...
Sources:
http://www.amnh.org/nationalcenter/youngnaturalistawards/1998/bees.html
Glossary:
Pollination: The process by which plant pollen is transferred from the male reproductive organs to the female reproductive organs to form seeds. In flowering plants, pollen is transferred from the anther to the stigma, often by the wind or by insects. In cone-bearing plants, male cones release pollen that is usually borne by the wind to the ovules of female cones.
Thursday, July 3, 2008
Entry 4: 3/7/08
I can conclude that global warming has a devastating impact on the North and South Poles, where its effect is greatest. Over the past three entries, I found out that the rising temperatures has caused many problems for the wildlife. The polar bears, penguin species and cetaceans are only a minority of the vast wildlife in these two environments. They are all affected by the decrease in sea ice in the Arctic and Antarctic. The sea ice affects many animals directly or indirectly. In the case of the polar bears, the bears need the sea ice as a "base" to hunt seals and other prey. They also need the sea ice as a surface for them to rest, breed, raise their cubs and live in. The declining sea ice has caused the deaths of polar bears as some of them tire out from swimming vast distances to find sea ice to rest on and drown. Unlike dolphins or whales, they cannot stay in the water for long periods of time. In the case of the penguins, because of the decline of sea ice, krill, the source of food for some species of dolphins, has declined considerably. With the lesser numbers in krill, the population of some species of penguins has also decreased.
Also, the decline of sea ice has decreased the land which the penguins can breed and raise their young. Also, with warmer winter temperatures, sea ice breaks off often, and penguin chicks are often stranded and die.
Also, the decline of sea ice has led to the cetaceans, whales, dolphins and porpoises to decline as well. This is because krill numbers have decreased, and thus there is lesser food for some species of whale or dolphin, which mostly depend on the krill for food. Also, warmer temperatures might kill some species of whale, as some whale species cannot survive in warmer water.
This is the one result of the sea ice declining. Many species of animals are affected, causing a chain of events which end up in the whole ecosystem of the North and south Poles being affected as a result. I feel that we humans are responsible for much of the decline of sea ice. Over the centuries, because of our constant burning of fossil fuels and the production of carbon dioxide and other greenhouse gases, we have led the world temperature to skyrocket until in the 21st century, which we start to take action and cut down on the emission of greenhouse gases. However, it is not to late to act now. However, if we do not continue to do nothing, the North and South Poles will melt into nothing, and many species of wildlfe would have been extinct. Do we want this to be the world which our children grow up in?
Also, the decline of sea ice has decreased the land which the penguins can breed and raise their young. Also, with warmer winter temperatures, sea ice breaks off often, and penguin chicks are often stranded and die.
Also, the decline of sea ice has led to the cetaceans, whales, dolphins and porpoises to decline as well. This is because krill numbers have decreased, and thus there is lesser food for some species of whale or dolphin, which mostly depend on the krill for food. Also, warmer temperatures might kill some species of whale, as some whale species cannot survive in warmer water.
This is the one result of the sea ice declining. Many species of animals are affected, causing a chain of events which end up in the whole ecosystem of the North and south Poles being affected as a result. I feel that we humans are responsible for much of the decline of sea ice. Over the centuries, because of our constant burning of fossil fuels and the production of carbon dioxide and other greenhouse gases, we have led the world temperature to skyrocket until in the 21st century, which we start to take action and cut down on the emission of greenhouse gases. However, it is not to late to act now. However, if we do not continue to do nothing, the North and South Poles will melt into nothing, and many species of wildlfe would have been extinct. Do we want this to be the world which our children grow up in?
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