Lesson 3: All in a drop of pond water under the microscope

		variety of desmids/diatoms crescent shaped diatom
		water bear (tardigrade) water flea (daphnia)
		hydra Paramecium
		vorticella spirogyra
		rotifer volvox

Hi,

I will never forget what I saw in a drop of pond water under the microscope.

I would like to share the wonder with you here.

Which of the above carry out photosynthesis (=producers), which eat other organisms (=consumers), which are decomposers (=feed on dead organisms)?

Producers use sunlight to make glucose. Glucose is then changed by metabolic processes into other complex organic molecules such as cellulose, starch, proteins, fats and others.These are in turn used for energy release and growth and reproduction.

Producers also release oxygen into the water. Oxygen dissolves into water and allows all aquatic organisms to carry out respiration.

Phytoplankton (=microscopic green plants/algae) are the start of all food chains in the oceans, small and large water bodies.
Phytoplankton is eaten by the slightly larger zooplanktons (=microscopic animals). Can you name some from the from the videos?

Here are the videos:

Can you match the list of names with the organisms that you saw in the videos?

amoeba, desmids, diatoms, Paramecium, vorticella, rotifer, daphnia/water flea, volvox, tardigrade/water bear, hydra, bacteria, spirogyra

Divide the list into producers and consumers.
Divide the list into unicellular and multicellular organisms.

Q: Why is it that many of the organisms have fuzzy/blur outlines?

A: the edges of the organisms are lined with tiny cilia which beat at high speed to draw tiny food particles for the organism to feed on. This gives the blurring effect.


Cheers

Postscript:

Here is my musical answer to the last video above — a few clips set to the "Minute Waltz" (appropriately pronounced 'my-NYOOT', 'not MIN-nut') by Chopin. Enjoy.

Disease scares from our live-stock and food animals

Hi,

Today I will write about the Ebola scare in pork from the Philippines.

Bird flu from China, Sars from Hong Kong, Measles, Cow pox, Mad Cow disease, small pox, Hepatitis, Rabies, AIDS, foot and mouth disease...What do they all have in common?

Answer: They are all diseases that spread from a host animal to man. In the host animal, these diseases are usually not deadly (benign) and they might cause discomfort but not necessarily death.

Some of these disease have been around longer than others. The newer ones are HIV (reported first in 1981 but thought to have originated in non-human primates in sub-Saharan Africa and transferred to humans early in the 20th century.), Ebola in Africa (reported in 1976), Ebola in Philippines (reported in 2008), SARS in China (reported in November, 2002) and Mad Cow Disease (first described in 1921 as Creutzfeldt-Jakob disease with a new variation from eating infected cows emerging in Britain in the mid-1980s).

• Bird flu was first documented as a pandemic in 1918-19; measles was first documented by the Persian physician, Muhammad ibn Zakariya ar-Razi (860-932) and the virus was isolated in 1954.
• Small pox has infected humans for 12,000 years; inoculation of material from smallpox blisters to induce a mild infection was possibly practised in India 3,000 years ago but is documented in China from the 10th Century. This was effective at giving immunity but risky. Edward Jenner in England documented the benign disease, cowpox, as a safe immunisation method in 1796 and thus created the first vaccine.
• Cholera first caused a pandemic in 1816 in Bengal, India. It has no particular animal host but survives in aquatic environments between outbreaks.
• Rabies is a disease of mammals; the name 'rabies' originated at least 5,000 years and was first written about around 1930 BC.

I will write about these in other posts.

What do all these diseases have in common?
The pathogens or causative agents all originated in animals that man handles either as food, as draught or transport animal, or came into contact accidentally.


Ebola in pigs in the Philippines
This is the latest scare, reported on 10th Dec 2008. Pork from 4 piggeries in northern Philippines showed the presence of Ebola-Reston virus.

It was first reported in crab-eating macaque (monkeys) in 1989. Two more outbreaks occurred in 1992 and 1996 in Southern Philippines and it was always confined to the monkey population and people in direct contact with the infected monkeys. It produced flu-like symptoms. The Philippine strain is a non-fatal.

What is so scary about this Ebola if it is never fatal in monkeys?
Ebola-Reston is a monkey virus that produced flu-like symptoms in monkeys and man. When it jumped species, as it did in Dec 2008, and started infecting pigs, then there is a chance that a mutation has occurred and the virus is now a virulent and fatal strain. If the changes that it has inherited makes it possible to jump species to man and people who handle the pigs in piggeries, then it can spread into the general population, i.e. people who do not go near a live pig but only eat pork and live in a neighbourhood where piggery workers live.

Why does the word Ebola evoke such fear in scientists?

SIDE NOTE: Diseases that originated in or are harboured by other animals are called 'zoonoses', or zoonotic diseases. Generally, humans get infected by accident and it is a dead end for the organism, even when they cause major pandemics like bubonic plague. Eventually, humans become too few in numbers where the outbreak occurs, either through death or by gaining immunity and the bug goes back to their natural host. By this definition, malaria is not a zoonosis — the disease needs to pass through both humans and mosquitoes to survive. Sometimes a mutation occurs and a new disease arises that depends solely on humans, like measles, which could have come from cattle or dogs. In other words, the disease can now spread from person to person with the need of any animal host

There are 3 other types of Ebola in Africa which cause fatal haemorrhagic fever and have killed hundreds. That it has not killed mny more is partly due to the extreme fear it induces in people, who flee the towns and villages where it breaks out. If the new strain of virus in pigs is virulent like the ones in Africa, its impact on humans is unimaginably unknown.
Three global watchdogs, the World Health Organisation, the United Nations' Food and Agriculture Organisation, and the World Organisation for Animal Health are testing these farm and the slaughterhouse workers for the virus. Pork from these farms are tested and people in the Philippines are asked to eat only well cooked pork. Pigs from the 4 affected farms are quarantined and transport of pigs from these farms is not allowed.

Why are so many of these new disease deadly? Why are we not afraid of the good old common cold?
These are new diseases to man. The human body has evolved its own immune system over millions of years to protect the body against human diseases. The body's white blood cells "recognise" the old germs (pathogens) and have the correct ammunition to kill them and protect the human body from the invaders. However, when pathogens from other animals get into our body, our body do not even recognise them as pathogens, and leave them alone to ravage the human body. An analogy would be, if the enemy only wears red for many generations, and an enemy that wears green comes along, our armies do not even know that they are enemies and turn a blind eye towards them. The enemy will have a free hand to pillage and plunder your country (=your body). As scientists say, we are "naïve" to the pathogen.

A child with smallpox. Fortunately, smallpox is now extinct — the first disease in history to be eliminated forever.

Hellish Ebola in Africa, for man and gorilla

Ebola haemorrhagic fever was first documented in 1976 in Zaire and Sudan in Africa. It spread rapidly from human to human through to contact with body fluids and blood. It is also spreading fast within the Lowland Gorilla population too, and caused tens of thousands of deaths in the past decade.

A biosuited scientist (top) and a dead gorilla. Click the gorilla image to find out why Ebola is such a serious problem for gorillas and how they can be helped

The host species for the virus is a fruit bat. (The bat does not get sick and is a natural reservoir of the virus.) When the virus jumped species from bat into man or gorilla, it caused internal(haemorrhagic) and external bleeding, fever and diarrhoea and eventually 50% to 90% of the infected died painful and rapid deaths. The disease is not treatable as no vaccines exists for it.

Protozoa, bacteria, viruses and prions (non-living protein disease-causing agents) reproduce much faster than we do. So they can evolve new ways to breach our defences faster than we can acquire natural immunity (which can be gained only at a cost of death and illness). They also thrive in conditions of high population densities and poverty that exist in much of the world. We rely on human ingenuity to devise treatments like new drugs, and preventives like hygiene and vaccines to overcome these shortcomings.

Cheers

How would we want to live in 2025 and beyond?

Incan idol and Aztec calendar, remnant artefacts of vast urban societies that collapsed due to environment damage, climate change and hostile neighbours

Hi,

Here is a riddle for you (one answer is at the end of this post):

What do camels and frogs have in common?

But first, I read a very thought provoking article in the Straits Times dated 10 Dec 2008. Entitled "Back to the future", it was authored by Mr Ho Kwon Ping from Singapore Management University.

I have always been fascinated by the documentaries shown on National Geographic and the History Channel, on ancient civilisations, how they flourished for hundreds of years and then collapsed suddenly. Sometimes they leave behind great monumental buildings, beautiful temples, impressive dams and irrigation networks, gargantuan pyramids, and some other intriguing structures that we still do not know what their original purposes were to the builders and the occupants.

The key points Mr Ho makes in his article are as follows:

• 100 years from now, we can expect a world where multiple civilisations would co-exist just like in the past. Western civilisations, which has dominated the world for the past several hundred years, would have declined in its influence, the world would be more like in 1652.


• In 1652, England was a powerful nation, the Japanese shogunate was celebrating 50 years of power, the Manchu dynasty of China was very virile and influential and the Taj Mahal was completed in India.


• East Asian and Islamic civilisations were more advanced in science than in Europe.


• The Chinese, Indian, Islamic and Western Civilisations were all in contact with each other but one was not dominant over the other three.


• It took 200 years from 1652 to 1852 for the two ancient civilisations of China and India to fall. (It would take that long for them to rise again.) Western cultural norms will no longer be how societies will be measured by 2025.


• By 1752, western imperialism, colonialism and domination of economic, military and political power occurred. Two world wars were also fought in the last 100 years.


• By 2025 China, India and the Islamic world will be re-ordering the world. It will be the much feared (by Westerners) 'clash of civilisations'.

According to the author, one cause for all these changes in power and dominance is urbanisation. When a country has more people living in urban settings than in the countryside, then the country would have factories, armies and navies that propel that country into a powerful nation. China is expected to reach this point by 2015 and India by 2050.

While there is a lot of over-simplification in this description (for example, in defining "civilisation" - how do you talk about a single 'Western civilisation' when European nations historically have been virtually in constant war with each other?), I believe his prediction (of Indian and Chinese dominance) will not necessarily come to be. Not unless the environmental impact of man is taken into account. Gaia cannot support 9 billion ^ref1 people if everyone consumes the resources of the earth with abandon like people in the first world countries. The world's resources would not be sustainable.
This issue is covered in the book, "Collapse" by Jared Diamond. He contends it has always been environmental degradation that led to collapses of civilisations throughout history.

I have placed many haunting images here from the web on such civilisations with populations of thousand or even millions living in complex urban or city-like places with equally complex agricultural services that collapsed due to neglect of sustaining the environment.

In his book, written in 2005, the examples given covered a longer period of time, and more continents. I am still reading the book but have this much I would like to share with you.......

Ancient Egypt, lasted nearly 4,000 years through alternating periods of stablilty and anarchy. Egypt's longevity was owed to the endless rise and fall of the Nile's annual flood and its fertile silt. It was almost impossible to exhaust but the great dynasties were twice brought down when climate shifts interrupted the annual floods. Ultimately, new empires in Europe and Asia brought the rule of the Pharaohs to an end, chiefly Persia and Rome. ^ref2

Easter Island civilisation flourished from around 900 AD, producing the famous stone figures weighing up to 270 tons, and a writing system. By the time Europeans arrived in the 1770s, the island was barren, tree-less, without livestock and with an illiterate population, too few in numbers and resources to have achieved such flowering of culture. ^ref3

How did the Islanders deplete their natural resources so completely? Didn't they realise what they were doing? According to Jared Diamond, they didn't:

"Gradually trees became fewer, smaller, and less important. By the time the last fruit-bearing adult palm tree was cut, palms had long since ceased to be of economic significance. That left only smaller and smaller palm saplings to clear each year, along with other bushes and treelets. No one would have noticed the felling of the last small palm."

The Central- or Meso-American Mayan civilisation collapsed in the 9th Century. There are competing theories on why this happened, among them foreign invasion. But most ideas point to ecological catastrophes of various kinds, including social revolt due to over-exploitation of the people to build temples like the one pictured above. Drought, slash-and-burn agriculture and collapse of trade are other factors. That it was no one thing would have made it hard for the Mayans to see the disaster coming.

Sumeria in ancient Mesopotamia (modern day Iraq) "...fell to an Elamite invasion during the rule of Ibbi-Sin (ca. 2004 BC). It is believed that invasion was successful because Sumerian agriculture was in decline, so Sumer could not maintain a sufficient army. The root causes of that decline are still debated; some say it was caused by a long period of drought, others, that it was an inevitable consequence of Sumerian irrigation, which caused increasing salinisation of the soil and decline in its fertility." ^ref4

Angkor Wat in Cambodia, was a vast (3,000 km²) city of at least 500,000 inhabitants at the centre of a Hindu civilisation covering much of Indo-China that collapsed in the 15th Century due to drought, deforestation and environmental degradation. ^{ref5 ref6}

Borobudor in Java. This vast Buddhist stupa built during the Sailendra dynasty was abandoned for unknown reasons. A volcanic eruption, climate change and hostile neighbours are some postulated reasons.

Mr Ho writes that the downfall of of every single civilisation since time immemorial has been hubris. What is hubris? It is the greatest danger to any civilisation, the quality of believing what you want to believe of yourself. It is a lack of self-doubt which eventually clouds wisdom and overrides our better judgement. As the saying goes, 'pride comes before a fall'. A flaw in this argument is that the "fall" of civilisations has often been due to exhaustion of the environment through over-exploitation. You could say this was in turn due to never doubting that they would triumph over nature - or "hubris" - and yet, the destruction of the environment was often so slow that the more bountiful past was beyond human memory.

Of course, we have no such excuse today. I sure do hope there will be no collapses due to environmental degradation as proven time and again by history. Efforts by enlightened governments and political leaders around the world to take care of our environment and natural resources will go a long way to controlling our quality of life and our destiny. In the past, new civilisations would arise in less despoiled parts of the world. Now, this is no longer possible. The degradation is global. Whether there is one or many centres of power in the future is irrelevant: we are all gonna have to hang together (i.e. all nations must come together and take care of the environment) or we will hang separately (face civil collapse as nations point fingers at one another).

. . . . .

The answer to the riddle I gave at the start is connected with the cartoon above and an old proverb that "If the camel once gets his nose in the tent, his body will soon follow." The camel's nose, like the tepid water for the frog, is such a small matter that we accept it, and the next advance, and the next, until...

Cheers

Footnote: October 9, 1997, The Washington Times, The Gore population problem

"We're actually beginning to experience some good news around the world with the beginnings of a stabilization in world population," Mr. Gore intoned with his usual deadly earnestness. "But the momentum in the demographic system is such that we're inevitably going to go to 8 or 9 billion. The question is whether these changes [in reproductive habits] will keep us from going to 10, 12, 14 billion."

Al Gore is a former US Vice President, Nobel Laureate and author of the documentary film, An Inconvenient Truth. This editorial from 1997 mocks Al Gore's concern. I wonder what the newspaper's editorial stance is now, more than a decade later? See the full article here: The Gore population problem

Return

Lesson 3: Down Syndrome testing

Hi,

Today's Straits Times carried an article entitled "Safer Screening for Down Syndrome".
I want to share some of my own thoughts on this topic that we usually cover under the chapter on Genetics in Secondary 4 Biology.

What is Down Syndrome?
This is a chromosomal disorder or mutation that results in a child being born with 47 chromosomes instead of the usual 46. (The extra chromosome was incorporated into the egg cell during meiosis.) The child with this syndrome (= a host of medical problems) will usually show learning disabilities, and have thicker and shorter neck and will have other health problems.





Who will give birth to Down Syndrome babies?
Pregnant women aged 35 and above are usually advised to test for DS as they have higher risk. This does not mean that younger women will not have DS babies, but just that the chances are smaller.



Why test for Down Syndrome?
Since this is a genetic disease parents would be worried of having such a child. There is no cure for this disease. The child would require more attention than a normal child and the medical costs would also be higher as the child has many health conditions that needs to be addressed. The parents must prepare for this.


How to test for Down Syndrome and other genetic diseases?

There are many tests:

1. Amniocentesis
   Click on this link to view a Youtube video on how it is done by a doctor.
   
   In this procedure a needle is inserted into the womb/uterus and some of the amniotic fluid(fluid in the "water bag" that is found around the foetus) is drawn into a syringe. The fluid contains some cells from the baby. These cells will be examined under the microscope and chromosomes will be examined and counted, (chromosome mapping). If the number of chromosomes is more than 46 or less than 46 than it indicates that the baby will probably have a genetic disease.
   
   


2. Chorionic villus sampling or CVS
   Click on this link to view a Youtube video on how it is done by a doctor.
   
   In this procedure a needle is inserted into the uterus and some cells of the placenta will be drawn into a syringe. The cells of the placenta, especially the villus, will be made of cells from the baby and not from the mother. Again chromosome mapping will show up the chromosome numbers and abnormalities.


3. Blood testing for chromosome mapping
   Click on this link to view a Youtube video on how the doctor uses blood taken from the pregnant women to look for cells belonging to the foetus. Once the foetal cells are identified and isolated, chromosome mapping can again be applied to test for chromosomal abnormalities.
   
   


4. First Trimester Combined Screening.
   This is a very new procedure that I just read about in today's ST. This procedure is better than amniocentesis and CVS as it is non invasive, ie no need to stick needles into the uterus. It includes a blood test to look for abnormal levels of certain hormones and proteins and a ultrasound scan to measure the thickness of a fluid filled tissue at the back of the foetus neck. then a computer programme is used to calculate the woman's the risk based on her age, family history, and the results of the blood test and ultra sound scan.

The FTCS test is better than the other tests for the following reasons:

1. It is non invasive. There is a 1% risk of miscarriage in amniocentesis and CVS


2. It is cheaper, only about $300 to $350. Amniocentesis and CVS costs more than $1000 each


3. It can be done at a earlier stage of pregnancy, within 11 to 13 weeks of pregnancy.
   Amniocentesis can be done between 10 to 14 weeks and CVS between 15 to 20 weeks of pregnancy


4. As it is non invasive and the chances of miscarriage is low, more pregnant woman would like to consider it and the detection rate is about 90%.

Click on these links to view more videos on tests during pregnancy.




Cheers

Lesson 2: Can your heart run on battery?

Hi,

Yes, your heart can run on battery. Pacemakers are small electronic devices that regulate heartbeats and they run on battery.

Why have battery operated heart?

It can prevent stroke in the elderly.



It is fitted if the heartbeats are too slow or too fast or irregular.
These arrhythmic heart beat can lead to stoke or even sudden death.
Atrial fibrillation is when the upper heart chambers are not pumping blood into the lower chambers (ventricles) normally.



If the flow of blood out of the heart is slow, or sluggish, then blood will start to form clots or lumps. These lumps will then break off and move along the blood vessels and may block the blood to the brain causing stroke(brain attack), blood to the heart muscles causing heart attack or blood to the lungs causing breathing problems (lung attack).

Who can have pacemakers?

People who have fainting spells, near blackouts and breathlessness after walking.
Pacemakers have been around for 50 years.
More than 3,000 people in Singapore have them. The cheapest model is only $3000, when subsidised by the government.
Each year about 75 people have pacemakers fitted into them in Singapore.

How does the pacemaker work?

The battery sends electrical signals to the atria to make them pump normally.
If the ventricles are not working normally, a 2nd or 3rd wire can shock the heart to beat properly. This is called Implantable cardioverter defibrillator (ICD)
If the heart stops beating, as in sudden deaths in athletes, the pacemaker will shock it into working too.

Is it true that pacemakers are affected by telecommunication devises?
Yes. They have to keep away from mobile phones, microwaves, MP3 music players and airport electronic screening as they interfere with the battery's electrical signals.

What is AED?

Ambulance personnel are usually trained to use the Automated External Defibrillator or AED. It is simple to use to revive the heart that has stopped or has irregular heartbeat.

This is a portable light-weight electronic devise that is carried in most ambulances, fire and police vehicles. In Japan, it can be found in railway stations, shopping centres, health clubs and other places where sudden cardiac arrests may occur.




Cheers

United Nations forum and REDD

Hi,

For the next two weeks the United Nations Forum is meeting in Poznan, Poland, on how to battle climate change. Their main agenda being:

Protect the remaining tropical rainforests

How?

Stop or slow down the cutting of forests for timber and agriculture

Why?

Trees are known as "carbon dioxide sinks" as they soak up and store CO₂ in their tissues during photosynthesis. This carbon dioxide will be released back to the atmosphere when trees are burnt or when they rot, as when they are cut down and the leaves and branches touch the soil. The decomposers in the soil, soil bacteria and soil fungi, will cause decay to take place. The organic molecules (carbohydrates, proteins and fats or oils) will be broken down to release energy for the decomposers. The wastes will be CO₂, which goes back into the air.

What is the problem with CO₂ going into the air?

1. The normal concentration of CO₂ in the air has been 0.03% for millions of years. Since the advent of man's penchant for burning fossil fuels, the concentration has been increasing alarmingly.


2. Cutting down of tropical rainforest further exacerbates the increase in CO₂ concentration in the air. Deforestation contributes to 20% of CO₂ emissions from human activities.

Carbon dioxide is a greenhouse gas. This means that it is like a warm blanket on the earth, not allowing the heat on earth from escaping into the space. Heat come to the earth from the sun in the form of light energy/solar energy. Most of this light energy is used to warm up the air, the soil and the ocean. Only about 1% is absorbed by plants and phytoplankton(algae in the oceans and water bodies) during photosynthesis to convert light energy into chemical energy. Glucose is formed in this process. Glucose is then changed by the metabolic processes in the plant/algae into organic molecules that the plant need for its energy, growth and reproduction needs. (Remember that plants do not have mouths; they get their energy in the form of light energy. Animals have mouths. [vaay illa jeevan ;-)] Animals eat their energy in the form of chemical energy i.e. food molecules ( carbohydrate, proteins and fats).

Since burning of fossils fuels in large quantities releases CO₂, the plants cannot remove the excess quickly enough. This build up of CO₂ causes the warm blanket to become better and better at keeping the warmth in the atmosphere. This in turn causes climate change.

United Nation countries have agreed to cut greenhouse gases by 5% by 2012 during a meeting in 1990 in Kyoto, Japan. This agreement or treaty will expire in 2012.

The Poznan meeting this week will consider "pay-to-preserve forest scheme". This scheme is also known as REDD or Reducing Emissions from Deforestation and Degradation.

What is REDD?

In this is scheme the richer countries would pay to maintain forests in tropical regions in poorer countries to prevent global warming.

Billions of dollars will be collected from donor countries and be given to developing countries/poor countries so that they will protect their rainforests.
The money will go towards:

1. preventing illegal logging


2. preventing forest fires


3. settling land disputes due to loss of livelihood of peoples who depend on the forest

A trial REDD programme will be starting with Indonesia. 70% of Indonesia's original forests have already been cut down. But it still has 91 million hectares. However, it is also the world's largest greenhouse gas emitter! Forest protection is important to prevent deforestation in this large S. E. Asian country.

We are familiar with the haze that we get in Singapore around June to August almost every year when the forests fires in Indonesia produces smoke, which the winds will blow towards Singapore.

The rich countries of the world have to help, with Australia coming forward to help in Indonesia:

1. an Australian company, Carbon Conservation teamed up with Aceh government.


2. Fauna and Flora International together with Australia's Macquarie Financial Services teamed up with three REDD projects in West Kalimantan and Papua governments.


3. New Forests, Australia teamed up with Papua government.


4. The government of Australia pledged $29m to protect, rehabilitate and drain peat swamps in Kalimantan. Peat swamps are wet throughout the year but during the dry seasons will catch fire spontaneously. The fire will start sweep through the forest quickly and are difficult to put out. (Peat is low grade coal and if found on the surface ie no need to mine for it, as in Kalimantan. This also means that they are easily combustible if dry. Since it is found on large areas of the ground, it will take months of arduous effect to put out these fires.)

The above projects if managed properly will not only preserve the forests, but also empower the locals to breathe clean air, maintain soil fertility and provide employment.

Quiz time: match the answers to the questions

1. Plants that photosynthesise are called... (remember, not _all_ plants do)


2. An example of 'heterotrophes' is...

Answers:

1. Mushrooms


2. Autotrophes

Click here to hear a song on Youtube by Midnight Oil on the issues of deforestation.......

Song lyrics: River Runs Red

So you cut all the tall trees down,
you poisoned the sky and the sea
You've taken what's good from the ground
But you've left precious little for me

You remember the flood and the fall,
we remember the light on the hill
There should be enough for us all,
but the dollar is driving us still

River runs red, black rain falls, dust in my hand
River runs red, black rain falls, on my bleeding land

So we came and we conquered and found
Riches of commons and kings
Who strangled and wrestled the ground
But they never put back anything

Now i'm trapped like a dog in a cage
Wherever the truth is pursued
It must be the curse of the age
What's taken is never renewed

(hirst/moginie)

Cheers