1 sophomore - DOST Sci

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2 0 0 0 - 2 0 0 1 V o l . 20
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THE PHILIPPINES’ ENDANGERED SPECIES
As the most intelligent creatures on earth, we should
learn to understand the balance in nature and to
respect all creatures no matter how big or small they
are.
AN ORGANISM CALLED EARTH
It is said that the Earth when viewed from
outer space, looks like a single-cell organism.
Is it?
THE FOOD CHAIN: WHO EATS WHO?
Every organism has its significant role to
play in food chains that are the web of life.
N o . 3
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THE DELICATE RELATIONSHIP BETWEEN
THE BIOSPHERE AND MOTHER EARTH
Unless a healthy balance in the biosphere is
maintained, Mother Earth is put in peril. Where
does that place us?
R E G U L A R F E AT U R E S
3 Science & Technology News
5 Filipino Scientists and Inventors
Medical Facts and Fallacies
9 Livelihood Technology / I’d Like to Know
10 Cyber World
BOARD OF ADVISERS
Violeta Arciaga, Jaime F. Bucoy
Jose C. Calderon, Victoria V. Cervantes,
Juanita M. Cruz, Belen P. Dayauon
CONSULTANT
Merle C. Tan, Ph.D.
DIWA OFFICERS
Saturnino G. Belen Jr. President
Amada J. Javellana
14 Earth Care
16 Investigatory Projects
19 Pseudoscience
Executive Vice President
Enrique A. Caballero,
Reynaldo M. de la Cruz,
William S. Fernando,
23 More Activities To Do
Jose Maria T. Policarpio, Elma L. Ropeta,
24 Mind Games
EDITORIAL BOARD
Lourdes F. Lozano Executive Editor
WilliamS.Fernando Managing Editor
Alfie “eLf” V. Mella Magazine Editor
Virgie Naigan Art Director
Silvano C. Santiago Cover Design
Jose Valeriano P. Linay Layout Design
Silvano C. Santiago Illustrator
Lourdes F. Lozano Vice Presidents
R
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Telephone numbers: 843-4761 to 66.
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SOPHOMORE
Estrogen Fails Test as a Treatment
for Alzheimer’s Disease
E
strogen will probably not
restore or even protect the
mental functions and the
memory that patients are
losing to Alzheimer’s
disease, the scientific journal
of the American Academy of Neurology
published in one of its issues.
Researchers from Taiwan gave
estrogen to 25 postmenopausal women
with mild symptoms of Alzheimer’s
disease. After 12 weeks, the patients
scored no better on tests of memory,
concentration, attention and other mental
abilities than the 25 other patients who
had been taking an inactive pill, called
the placebo. The physicians’ evaluations
of the patients’ disease progression also
failed to find the differences between the
two groups. This study just proved that
estrogen cannot probably be considered
as a treatment for Alzheimer’s disease.
Source: http://www.sciencedaily.com
Study Finds France has the World’s
Best Health Care System
T
he United States spends
about $3,724 per person
on health care each year
but its overall quality
care ranks only 37th in
the world, says a World
Health Organization analysis. It
concluded that France provides the best
health care all over the world, though it
does not spend that much on it. People
in France remain healthier than people
in any other countries worldwide,
because they consider environmental and
other ecological factors to maintain good
health and disposition.
Source: http://www.nando.net/
healthscience/story
SOPHOMORE
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I
ncreasing the amounts of
silica in the oceans may
remove large amounts of
carbon dioxide from the
atmosphere, delaying the
onset of global warming.
According to Kevin G. Harrison, Boston
College Geologist, an increase in ocean
silica levels can explain why atmospheric
carbon dioxide levels decreased by 30
percent during glacial times, a significant
change that has puzzled scientists for
decades.
According to Harrison, human
activity has doubled the amount of dust
delivered to the oceans. Until now,
scientists are unable to propose an elegant
mechanism to link this increase in dust
with decreasing atmospheric carbon
dioxide (pCO2). Harrison proposed a
mechanism, the Silica Hypothesis.
This hypothesis suggests that
increasing the supply of silica to the
oceans may alter pCO2 levels. The silica
present in the dust dissolves and becomes
Increase in Ocean Silica
May Delay Global
Warming
available for biological uptake. In glacial
times, increased silica levels shifted the
composition of species, changing the
distribution of plankton species. This
shift increased the ability of oceans to
remove carbon dioxide from the
atmosphere: decreasing the population of
coccoliths decreased the flux of calcite
to the sediments, which in turn lowered
Scientists Issue Caution
on the Use of Telomerase
T
he enzyme telomerase
has been receiving great
attention since 1998,
when
researchers
showed that introducing
this enzyme in human
cells extended the life-span of cells.
Telomerase expression was immediately
recognized as a useful strategy for
growing large number of cells required
for therapeutic procedures that are cellbased.
However, David Beach, of the
Wolfson Institute for Biomedical
Research (University College, London),
and his colleagues reported that using
telomerase to extend the life-span of
human tissue cells is associated with the
activation of c-myc oncogene, that may
present some level of cancer risks if the
cells are intended for therapeutic use in
humans.
Source: http://www.sciencedaily.com
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SOPHOMORE
pCO2 levels.
Harrison notes that the increase in
dust level suggests that the same diatombased mechanism may be at work today,
removing significant amounts of carbon
dioxide from the atmosphere, thus
slowing the rate of global warming.
Source: http://www.sciencedaily.com
SALCEDO L. EDUARDO
Veterinary Parasitologist
Are you fascinated with animals?
Have you ever wondered how they live?
What made them unique creatures? Then
you might want to be like Dr. Eduardo
who is one of the country’s best animal
scientists.
In his student days, Dr. Eduardo
committed himself to excellence. He
finished his Doctorate in Veterinary
Medicine magna cum laude at the
Araneta University Foundation in 1968.
He then went to the University of the
Philippines for his Master of Science
degree in 1973.
Dr. Eduardo underwent advanced
parasitology research training at a school
of Veterinary Medicine in Hanover,
Germany (1973-74), and got his Doctor
of Philosophy title in 1981 from the
University of London in England. He also
studied as a scholar at the Naturhistoriska
riksmuseet (Swedish Museum of Natural
History) in Stockholm, Sweden (1989),
and at the Faculty of Veterinary Medicine
of the University of Glasgow in Scotland,
United Kingdom (1989).
Because of his superior education
and expertise, Dr. Eduardo held important
academic and administrative positions at
the University of the Philippines (UP).
Presently, he is the chairman of the UP
Los Baños Department of Veterinary
Parasitology and Protozoology. He is also
the head curator of zoological museum,
and curator of animal helminth parasites
at UPLB’s Museum of Natural History.
Among his major awards are the
Outstanding Young Scientist in the
Philippines (1980), the Don Andres
Soriano Animal Science Research Award
(1981); the Most Outstanding
Veterinarian in Research, given by the
Veterinary Practitioners’ Association of
the Philippines (1985), and the Most
Outstanding Professional Award in
Veterinary Medicine, from the
Professional Regulation Commission
(1992).
He has attended numerous
international scientific conferences and
wrote scientific articles on animal
science.
Ear What?
Fallacy: Cleaning the ears
daily is a good health practice.
Fact:
Contrary to common belief
and practice, cleaning the ears daily does
more harm than good.
The ear serves as the organ of
equilibrium and hearing. It is divided into
three parts: the external, middle and
internal ear. Located in the external ear
are the visible part of the ear, called the
auricle, and the waxy, dirt-trapping
auditory canal.
The waxlike secretion of the ear
found in the auditory canal is called the
cerumen. The cerumen protects the
eardrum from damage. Foreign
substances such as dust and dirt stick to
the cerumen before they are able to reach
and cause damage to the eardrum. It also
serves as a protective lining that coats the
external ear. To remove the earwax
regularly is to strip the ear of its natural
protection. Doctors say that it enough to
clean the external ear with a cotton swab
once a week.
The earwax could also harden and
affect normal hearing, just like any
foreign body such as insects and cotton.
But removing these obstructions your self
may aggravate the problem. The
impacted earwax or foreign objects may
be pushed farther and damage the
eardrums. When this happens, it is best
to seek the help of an otolaryngologist,
a physician specially trained in treating
cases like these.
SOPHOMORE
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B
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O
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Marlene M. Gutierrez
T
he Philippines is teeming with life - be it
on land or water. Thousands of variety
of animals and plants are found in the
country. But many of the flora and fauna
in the Philippines are in danger of becoming extinct. Illegal
logging, massive deforestation, dynamite fishing, and
dumping of waste in bodies of water are just some human
activities that threaten the existence of several species in
the country, a good number of which are endemic to the
Philippines.
Each species of organism plays a significant role
in maintaining balance in the environment. As King Mufasa
in the book The Lion King said to his son Simba,
“Everything exists together in a delicate balance. As king,
you will need to understand balance and to respect all
creatures, because we are all connected in the great circle
of life.”
The disappearance or destruction of one species
will disturb the harmony found in nature. Living things
depend on one another for food. All the different things
that make up the biosphere - from a miniscule bacteria to
a giant elephant - have a unique role to play.
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The Sea Turtles. There are eight known species
of sea turtles or pawikans living in the warm waters of the
world. Five of these species can be found in the Philippines.
The most common species found in the country is the
Green Sea Turtle (Chelonia mydas). The four others are
the Hawksbill (Eretmochelys imbricata), the Loggerhead
(Caretta caretta), the Olive Ridley (Lepidochelys olivacea),
and the Leatherback Turtles (Dermochelys coriacea).
Unfortunately, the number of sea turtles in the
country is declining at an alarming rate. There is a high
demand for products made from turtle shell or skin such
as wall decors, jewelry, and musical instruments like guitars
and bonggos. In fact, for many years turtle by-products
were a major export item of the Philippines. Between 1970
to 1986 alone, the country supplied Japan (the world’s
largest importer of sea turtles) with a total 32,921 kilograms
of Hawksbill species. Humans have always hunted sea
turtles for food, and the demand for turtle by-products has
significantly increased. The pawikan trade has long been
outlawed but since it is very lucrative, poachers, fishermen
and other people take the risk of being caught.
The sea turtle evolved during the age of the
dinosaurs. It was the only reptile endowed with a shell. It
has undergone very little change in its 150 million years of
existence. Evolution of species is a result of the species’
response to changes in the environment that affect their
survival. The sea turtle, unlike other species, underwent
very minimal evolution because its shell adequately
protected it. With such an armor, an adult sea turtle has
very few natural enemies. It is ironic then that the sea
turtle which has overcome geological changes and has
survived until today, is on the verge of extinction because
of humans, a species that came into existence only
1.6 million years ago.
What is the government doing to conserve the
dwindling sea turtle population in the country? The
Department of Environment and Natural Resources
(DENR) has started the Pawikan Conservation Program
which is responsible for the formulation and implementation
of conservation and protection policies, management and
propagation schemes, and massive information and
education program to ensure the survival and growth of
the country’s sea turtle population.
What can ordinary citizens do to protect the
pawikan? Do not patronize turtle by-products such as eggs,
meat, shell or products made from turtle shell or skin. Join
organizations that preserve sea turtles’ nesting grounds.
Report people engaged in illegal pawikan trade to the Parks
and Wildlife Bureau’s Task Force Pawikan of the DENR
or the Haribon Foundation.
The Tamaraw. Another endangered species is
the tamaraw (Bubalus mindorensis), which is the largest
endangered land animal in the Philippines. It is found only
in Mindoro. The tamaraw is a small water buffalo. Many
people confuse it for the common carabao because they
look almost alike. However, the tamaraw is slightly smaller
and its horns grow straight upward, forming a “V,” instead
of a circular growth as in the carabao’s horns.
The tamaraw feeds mainly on grasses of various
species, but it prefers cogon grass. It is usually found in
dense vegetation along rivers and spends most of its time
in marshy areas. It can also be found in open grasslands
and forests with an elevation of more than 2,000 metres
above sea level. The tamaraw is usually by itself except
during the months of April to July, its breeding season.
From an estimate of 10,000 heads in 1900, the
tamaraw population has decreased to 369 heads in the
late 80’s. No wonder the tamaraw joins the list of the
Philippines’ endangered species. Destruction of its habitat
due to deforestation and habitat alterations, such as
conversion of forest land to residential areas, have
contributed to the decline of the tamaraw population.
Overhunting and collection for trophies have also taken a
heavy toll on the tamaraw.
To protect the tamaraw, the DENR runs the
Tamaraw Conservation Program which is designed to
prevent the extinction of the tamaraw, and to protect and
conserve its habitats. It carries out captive breeding
experiments, habitat characterization, maintenance of
Tamaraw Gene Pool in San Jose, Mindoro and conducts
public awareness campaign.
The Estuarine and Freshwater Crocodiles.
There are two species of crocodiles found in the
Philippines. These are the estuarine or saltwater crocodile
SOPHOMORE
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B I O L O G Y
(Crocodylus porosus) and the freshwater or Philippine
crocodile (Crocodylus mindorensis).
Both species of crocodiles, locally known as
buwaya, are obscurely colored. The back of the crocodile,
which is generally light brown in color, is covered with hard
and thick scales. Irregularly shaped black spots pepper
the sides of the body and upper part of the limbs. An adult
estuarine crocodile is about 4 to 5 metres long, while the
freshwater crocodile has an average length of less than
3 metres. The biggest crocodile to be caught was 9 metres
long. It was caught in 1981 in Jala Jala, Laguna de Bay.
The biggest saltwater crocodile to be caught in recent times
measured 5.34 metres long. It was caught in Palawan.
The estuarine crocodile is more widely distributed
than the freshwater crocodile. It is found in all the larger
islands of the Philippines including Luzon, Mindanao,
Palawan, Samar, Leyte, and Panay, as well as in foreign
areas from eastern India to northern Australia. Its habitats
are the mouths of rivers and muddy canals located near
the sea. It also dwells in mangroves and swamps. In the
Philippines, the freshwater crocodile can only be found in
the islands of Luzon, Mindoro, Masbate, Busuanga, Culion,
Negros, Samar, and Mindanao. It lives mainy in freshwater
marshes and small lakes, and is said to inhabit swampy
depressions, ponds, mangroves, and tributaries of large
rivers.
Overhunting and habitat destruction have resulted
in the decline of the population of both crocodile species
in the country. They have been hunted primarily for their
skin which is considered as one of the most prized leather
in the international market. A belt made from crocodile
skin costs 250 US dollars on the average, a handbag costs
about 4000 US dollars while a pair of shoes costs between
600 to 800 US dollars. Locally, a live crocodile can fetch
as much as 10,000 pesos.
Humans also hunt crocodiles because they pose
a danger to human lives and livestock.
Because most of the original habitats of crocodiles
have been converted to fishponds or have been cleared
for agricultural purposes, crocodiles can now be found only
in uninhabited areas.
The government has taken steps to protect the
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crocodiles. It operates and maintains the Crocodile Farming
Institute (CFI) in Irawan, Palawan. This is a joint
undertaking between the government and the Japan
International Cooperation Agency (JICA). The goals of the
institute are to conserve both species of crocodiles and to
contribute to the socio-economic well-being of the local
communities where the crocodiles are found through the
promotion of sustainable farming technology developed
at CFI.
The pawikan, the tamaraw, and the estuarine
and freshwater crocodiles are just some of the Philippine
animals that are in danger of becoming extinct. Other
species that have also been classified as endangered
include the cockatoo, flying lemur, bear cat, tarsier, dugong,
and peacock pheasant. The government and some private
agencies continue to launch programs to protect these
species. Let us be more aggressive in supporting these
programs if we do not want to break the great Circle of
Life.
1. Why is the pawikan trade lucrative?
2. Differentiate between a common carabao and a tamaraw.
3. What is the economic value of hunting crocodiles?
4. Identify human activities that led to the decline in the number
of pawikans, tamaraws, and crocodiles in the country.
5. What is being done to preserve the pawikan, the tamaraw,
and the crocodiles in the country?
Endemic - found only in a particular area
Endangered species - species considered to be in danger of
becoming extinct; only a few of its entire species remain in existence
Habitat - the place where an organism lives
References:
http://www.denr.gov.ph/green.htm
http://www.haribon.com
Angelika Erika Pamatigan
Liceo de San Pedro
Q: Can a fish drown?
A: Yes, a fish can drown. Fishes, like
people, need enough oxygen to live. A
San Pedro, Laguna
fish out of water is a fish out of its
element. A fish uses its gills to regulate
the amount of its oxygen intake from the
water it takes in.
When a fish is taken out of
water (H2O), and exposed to air for a long
period of time, it is deprived of oxygen
and hydrogen. This renders its gills
unable to control the oxygen intake. The
delicate balance cannot be maintained
and the gills inhale an overdose of
oxygen, causing the fish to experience
death by “drowning.”
And so, though not necessarily in
water, a fish can drown, too.
JELLY BITS
WHAT YOU NEED
One cup of water, 3 tbsp unflavored gelatin powder or crushed
gelatin bar, 1 ½ cup sugar, food coloring, vanilla flavor, margarine,
corn starch, kettle, egg beater, measuring cup, baking pan, knife,
sterilized candy jar, transparent plastic bag, stove
WHAT TO DO
1. Allow water, sugar and gelatin to boil. Stir occasionally. Once the mixture
starts to boil, lower the flame.
2. Using an egg beater beat the gelatin syrup for about 10 minutes. Then, add food
coloring, sugar and a drop of vanilla. Mix the ingredients thoroughly.
3. Grease the baking pan by spreading margarine on its surface.
4. Pour the gelatin paste into the pan.
5. Wait until the gelatin sets before cutting them into desired shapes and sizes.
6. Roll the gelatin in cornstarch.
7. Pack the jelly bits in dry, transparent plastic bags
8. Seal and store in dry, sterilized candy jars.
SOPHOMORE
9
I
Conditional
n this issue we will look at some new
commands and programming techniques.
The first command we will look at is the
INPUT command. This command allows
the user to enter data through the keyboard.
Let’s take a look at the sample program:
CLS
PRINT “What is your name”;
INPUT name$
PRINT “Hello”;name$
END
When you run the program it will display on screen
“What is your name?” with a blinking cursor to the left.
This means the computer is waiting for some input via the
keyboard. Let’s say we enter the name kristine and press
enter. The computer will then display on screen, “Hello
kristine.” Did you notice the question mark that the
computer displayed when asking you your name? If you
look at the code there is no question mark! The input
command by default displays a question mark while waiting
for the input from the keyboard. You can remove this by
placing blank quotes followed by a comma (“”, <-like this).
You can also choose to enter a phrase between the quotes.
The word after INPUT is called a variable. A variable is
used to represent another number.
Well, here is another example….
CLS
INPUT “Please enter a number:”; X
INPUT “Please enter another number:”; Y
PRINT “The sum of the numbers is ”; X+Y
END
This program should ask you for 2 numbers and
then display the sum. It is a very simple program but it
teaches us a thing or two. Notice that the variable doesn’t
have a $ sign after it unlike in the first program. You see,
there are two type of variables: numeric and string. A
numeric variable (the one without the $ symbol) is the one
being used when entering a number. A string variable
(the one with the $ symbol) is used when entering
words. You can call your variable almost anything.
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SOPHOMORE
Just make sure the name starts with a letter, has no
symbols (except the $) and is not a reserved word.
Reserved words are words like PRINT, INPUT, CLS and
all other commands.
Okay, here is another program:
CLS
INPUT “Please enter your name:”, name$
INPUT “Please enter the year you were born:”,
year
INPUT “Please enter the current year”, now
INPUT “Have you already had your birthday (Y or
N)?”, bday$
IF bday=“Y” THEN
PRINT name$;“is”;now-year;“years old.”
ELSE
PRINT name$;“is”;now-year-1;“years old.”
END
Say hello to the IF-THEN statement. The IF-THEN
statement allows the program to do different tasks
depending on the input of the user. Okay, before
we tackle the new command let us look at the
beginning of this program. Notice the use
of the different kinds of variables for
the different kinds of inputs required.
If a word or text is required, we
use a string variable, for
numbers we use a numeric
variable. Also, notice that
inside the IF statement we were
Programming
able to perform an arithmetic operation, subtraction in
particular, directly on the variable. This is only possible
with numeric variables.
Okay, now let’s look at the IF-THEN statement.
The structure of this command is:
IF <condition> THEN <statement>
ELSE <statement>
END
You can place a series of commands where it
says <statements>, but if you only have one simple
command, you can also use this structure (the else is
optional):
IF <condition> THEN <statement>
ELSE<statement>
Okay, let’s look at another example using
the IF-THEN command:
CLS
PRINT “Try to guess my secret number”
INPUT “Enter your guess”; guess
IF guess=6 THEN PRINT “CORRECT!”
ELSE “Sorry!”
END
There are 2 things to
take note of in this example.
Notice
that
in
the
guess=6, the six is not
enclosed in quotes. This is
because 6 is a number. In
the first example, we enclosed
the Y in quotes, that is “Y”. If the
condition resolves to a string
variable, then the string must be
placed in quotes, if it resolves to a numeric variable,
then the value is not enclosed in quotes. The second
thing to take note of is that the IF-THEN statement is
placed on a single line and there is no END IF. You can
do this only if there is just one command after the THEN
statement. Although the ELSE statement is optional it
should also have only one command.
The last command we will learn is the
GOTO command. This command lets the program jump
to specific lines of code. Take a look at the example:
CLS
PRINT “I have locked your PC with a secret
code!”
PRINT “If you can GUESS the code then you will
unlock your PC.”
INPUT “Make your guess”; ans$
start:
IF ans$=“GUESS” then
PRINT “You have figured out the password”
PRINT “Have a nice day”
ELSE
PRINT “Har-har! You can do better than that”
INPUT “Guess again”; ans$
GOTO start
END
The “start:” is not a command, it is called a label.
A label does nothing but marks off a certain line. If you
look at the ELSE statement it contains a command called
GOTO which instructs the computer to go to the specified
line. In our example, we are telling the computer to go to
the line labeled start. Another thing, text is case sensitive
so “guess” is different from “GUESS”. Have fun
experimenting.
SOPHOMORE
11
By Ernesto Buensuceso Ferreras Jr.
I
n the beginning, about three and a half
billion years ago, there were bacteria and
archaea, simple one-celled creatures
called prokaryotes that formed from
replicating organic molecules. Prokaryotic
cells have no nucleus and contain little
more than genetic material. The earliest prokaryotes were
phototsynthetic and autotrophic, that is, they produced their
own food molecules.
These primitive prokaryotes multiplied in great
numbers, invading the oceans and shores. They produced
gaseous oxygen which made Earth’s atmosphere aerobic.
This atmospheric change gave rise to the evolution of all
aerobic life.
Symbiotic Unions
About two billion years ago, prokaryotes began
to merge with one another either through membrane
infolding or endosymbiosis, or a combination of both.
Some cells evolved into large assemblies of specialized
parts by ingesting free-floating prokaryotes. For instance,
prokaryotes that breathed oxygen became the
mitochondria of these new cells, responsible for aerobic
respiration. Descendants of photosynthetic
prokaryotes became chloroplasts, carrying on
photosynthesis inside some of the new cells.
Over time, the prokaryotes that had
entered into symbiosis, or mutual alliances,
evolved into a new type of two-part organism
— the eukaryote, an advanced cell that carries
within itself a gene-bearing nucleus. The
emergence of eukaryotes was a leap in
evolution, far greater than any that has occurred
since. All the plants and animals we know today
developed from these early symbiotic unions.
Life on Earth was now on the road to
evolving more complex lifeforms. Organisms
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consumed huge amounts of atmospheric gases and
exhaled massive amounts of other gases. In the oceans,
they changed the water’s acid and base content. In short,
they were energetic participants in the regulation of their
world. Organisms and the planet Earth were constantly
interacting and the world had forever changed.
The world thus is one of cooperation. The bonding
of simple bacteria into a symbiotic union was essential to
the evolution of higher organisms. In other words,
teamwork between the physical world and the life it bears
is responsible for the diversity of life on Earth.
The Gaia Hypothesis
Living things alter the environment. For example,
plants get carbon dioxide from the air and give off oxygen.
Trees give off water through their leaves in a process called
transpiration. By adding humidity to the air, the trees
increase the number of rainstorms that occur.
As a result, the rain keeps the trees
watered. Also, rain clouds block the sun
to keep the forest from overheating.
Life and its environment can be considered as a
single entity that regulates physical conditions in order to
keep the environment suitable for the organisms to exist.
This concept of Earth as a cosmic organism is expressed
in a theory of nature known as the Gaia hypothesis (named
after the Greek goddess of the Earth).
The Gaia hypothesis was proposed by British
scientist James Lovelock. It proposes that all living things
and the environment in which they live work together like
the parts of one vast organism. It is the idea that the Earth
is a living organism (called Gaia) that functions as a unified
whole to regulate conditions in the air, land, and water.
For example, proponents of Gaia said it is Gaia
that has kept global temperatures from rising high enough
or dropping low enough to destroy all life. Gaia has
sustained the atmosphere and the oceans so that they
are suitable for living organisms. In effect, Gaia is the
largest manifestation of the symbiotic process.
Some scientists believe that the Gaia hypothesis
only serves as a convenient metaphor for the
interconnections among living beings. Other experts think
that research on Gaia may add to our understanding of
serious environmental problems, such as the greenhouse
effect and mass extinctions.
No Organism Is an Island
No organism lives alone. Each depends in some
way upon other living and nonliving things in its
surroundings. For example, a deer must have certain plants
for food. If the plants in its environment were destroyed,
the deer would have to move to another area or starve to
death. In turn, plants depend upon such animals as deer
for the nutrients they need to live. Animal wastes and the
decay of dead animals and plants provide many of the
nutrients plants need.
The living Earth is like an airplane. Thousands of
rivets hold an airplane together. If those rivets are removed,
the aircraft will fall apart. In the same way, our survival
and well-being depend on ecological relationships
throughout the world.
The natural world is organized on three main
levels: populations, communities, and ecosystems. The
structures, activities, and changes that take place within
and among these levels affect living things. Of these, the
most complex level of organization in nature is the
ecosystem. It is made up of a community and its abiotic
(nonliving or physical) environment, including climate, soil,
water, air, nutrients, and energy.
Thus, biological diversity — plants, insects, fish,
and other animals —can be compared to the
rivets of an airplane. It
is estimated that one
thousand species almost
become extinct each year,
and the figure may rise to
more than 10,000 a year —
or one species every hour —
in the next few years. If
more species are lost,
we are likely to meet an
ecological disaster in the near future.
The relationship then between humans and all
other lifeforms ensures our survival. Each and every
species plays a significant role in the life cycle of others.
Some species provide us with food; others supply cures
for deadly diseases; and others keep our environment
clean.
It is then imperative for us to help preserve other
species as well. If our planet isn’t safe for birds, fish, and
insects, then it’s not safe for humankind.
1. Discuss briefly the evolution of one-celled organisms into
multi-celled organisms.
2. Explain the driving force of evolution according to the Gaia
hypothesis?
3. How does the Earth keep its environment suitable for living
things to exist?
4. In what way do scientists regard the Earth as an integrated
system?
Abiotic – not involving or produced by organisms
Aerobic – occurring only in the presence of oxygen
Endosymbiosis – symbiosis in which the smaller organism dwells
within the body of its partner
Symbiosis – the living together of two different organisms in a mutually
beneficial relationship
References:
1. Bosveld, Jane. “Life According to Gaia.” Omni, October 1991.
2. Campbell, Neil A. et al. Biology: Concepts and Connections, 2nd
Edition. 1997. California: Addison
SOPHOMORE
13
Marlene M. Gutierrez
M
ore than one and a half billion people
greeted the 20th century. One hundred
years later, about 6 billion people
welcomed the 21st century. By the
22nd century, there would be about
11.6 billion human beings. The big
question is, “Does the Earth have the capacity to support
such a staggering number of people?”
A step to finding out the answer to the above
question is by looking at the health of the Earth’s major
ecosystems. As reported by Time magazine, “only a
comprehensive, global survey of the various ecosystems,
from oceans to forests, can show whether Earth as a
whole still has the ability to nurture the full diversity of
life and the economies of nations.”
These ecosystems include forests, agricultural
lands, grasslands, and coastal/marine and freshwater
areas.
To have a true accounting of the state of the
above ecosystems, the United Nations conducted a
study called the Pilot Analysis of Global Ecosystems
(PAGE). Preliminary results of the study were printed in
the April-May 2000 special edition of Time magazine.
The following descriptions of the various ecosystems
are derived from this issue of Time.
The forest ecosystem is home to two-thirds of
all species. It also controls climate and serves as a
water reservoir. Forty percent (40%) of terrestrial carbon
is stored in the world’s forests and its trees help prevent
the build up of greenhouse gases by absorbing carbon
dioxide from the air. Unfortunately, most industrial
nations (with the exception of Russia and Canada) have
cleared almost all their original forests. Some factors
that lead to the rapid shrinking of forests include fires
(which are caused by land clearing and climate change)
and logging (in developing countries, logging rate is
faster than tree growth!).
14
SOPHOMORE
About a third of global land is used for agricultural
purposes. However, three-fourths of this has poor soil.
The soil is enriched with fertilizers and pesticides which
kill helpful creatures, contaminate ground water, and
create dead zones in the oceans by stimulating growths
of algae which suffocate water-dwelling organisms.
Improper farming practices have also led to nutrient loss.
Also, 40% of agricultural land has been badly degraded.
One area particularly at risk is Latin America because
of erosion, nutrient depletion, and water stress spell.
Grasslands cover 40% of the world’s land
surface. This ecosystem is home to the largest
mammals, migrating birds, crops and livestock. All
human food grains originated in grasslands, and wild
strains of these crops help keep them resistant to
threats. Incidentally, only 20 species provide 90% of
the world’s food with maize, wheat and rice accounting
for more than half. Unfortunately, 80% of the world’s
grasslands are affected by soil degradation. Soil erosion
and desertification have diminished the ability of the
grassland to support livestock. Also, large areas have
been converted to farmland or used for urban
development.
Coastal/marine areas serve as home to
2 billion people. Two thirds of all fish harvested depends
at some point on their lives on coastal wetlands and
sea grasses or coral reefs which are rapidly disappearing.
Pollution, overfishing (fleets are 40% larger than oceans
can sustain), improper fishing practices (e.g. trawling),
cutting of mangroves, and climate change (warming
waters can cause the death of coral reefs) have led to
the deterioration of this ecosystem.
Because all organisms need water to survive,
the most critical ecosystem is the freshwater
ecosystem. Human water consumption increased six
times in the past century, which is twice the rate of
population growth. Today, people use 54% of the
available freshwater. Unfortunately, discharges from
industrial sites, mines, farms, and residential areas have
killed lakes and poisoned rivers. The massive diversion
of water from rivers has caused these rivers to dry up
even before they reach the sea. The introduction of
species that are not native to the lakes has disrupted
their ecological balance. For example, the introduction
of tilapia and Nile perch to Africa’s largest lake, Lake
Victoria, has upset the lake’s existing balance. These
two species yield 300 million-dollar worth of catch for
export. At the same time, they have crowded out
350 species of native fish that used to support the local
fishermen who can not afford the equipment needed to
fish for perch. With the 80% decrease in the native fish
population, many local families are now suffering from
malnutrition.
What about the Philippines?
Because it is an archipelago, our country has
one of the longest coastline in the world and has a vast
expanse of coastal waters and freshwater bodies which
consist of 421 rivers, 59 natural lakes and some 100,000
freshwater swamps. But according to Asiaweek, 362 of
the country’s 421 rivers are polluted to “varying degrees.”
A report made by Congress shows that Pasig River in
Metro Manila and Bued River in Pangasinan were among
those whose pollution levels have made aquatic life
impossible. Because the situation is so prevalent,
Congress now calls for a comprehensive measure to
allow systematic clean up of the country’s waterways
through the Clean Water Act. The bill includes putting
in place a nationwide water quality management and
water treatment system.
Unsound fishing practices have also contributed
to the deterioration of coastal ecosystems. An example
is San Miguel Bay in Calabanga, Camarines Sur.
According to Haribon Foundation, trawl fishing is the
main cause of the rapid deterioration of the bay and the
decline in fish production. Despite being one of the most
destructive fishing methods used in the country today,
trawling is very rampant in San Miguel Bay. Trawl fishing
is ecologically destructive because it scrapes the
substrate and depletes the bottom-dwelling organisms.
Many species as by-catch are thrown, wasted, and
snatched from their natural habitats. It also stirs up
sediments that may be transported to adjacent
ecosystems and cause the suffocation of corals, capiz
shells and other marine organisms.
Forest cover has shrunk to 5.5 million hectares
which is 18.3% of the total land area. If the country
does not take the necessary measures, this figure could
drop to as low as 7% by 2010.
Agricultural lands are also in a bad state. Soil
erosion badly affects 22 of the country’s 77 provinces.
This is compounded by the inability of Congress to pass
a Land Use law. Moreover, prime lands have been
destroyed by salt-water intrusion, which is a
consequence of massive destruction of mangroves.
The different ecosystems are the Earth’s life
support system. They regulate climate, purify and store
water, produce food, recycle wastes and carry out other
functions essential for survival. These ecosystems are
linked by an intricate network that has made them
interdependent such that inflicting damage to a tropical
rainforest in Brazil, for instance, could affect countries
even on the other side of the globe. For example,
massive deforestation in the mountains of Mindanao has
resulted in floods in grasslands or agricultural lands
below. Destroying reefs and lagoons, draining wetlands,
and cutting mangroves damage coastal/marine areas.
Mine tailings, effluents from factories, and agricultural
by-products can also destroy coastal ecosystems as
rivers transport these pollutants to the coasts.
Nature can heal itself. But up to what point can
Earth withstand the shocks imparted by humans and at
the same time renew itself so that it can continue to
deliver goods and services to its inhabitants? Failure to
heed the signal that Mother Earth is in pain could mean
the further decline of our planet’s ability to support nature
and economies. Failure to act now could mean not only
saying goodbye to economic development but to survival
as well!
1. Cite some human activities that put our country’s
ecosystems in an unhealthy condition.
2. Why are ecosystems considered the Earth’s life
support system?
References:
1. Time Magazine special edition, April-May 2000
2. Asiaweek March 10, 2000
3. Newsweek Magazine December 27, 1999 to
January 3, 2000
4. http://www.haribon.org.ph SOPHOMORE
15
I N
C O O P E R AT I O N
W I T H
T H E
DEPARTMENT OF SCIENCE AND TECHNOLGY
The Effect of
Ipomoea aquatica
(Kangkong) on the
Blood Cholesterol
levels of
Oryctolagus
caniculus (Rabbits)
16
SOPHOMORE
ABSTRACT
Kangkong is a staple in the diet
of many Filipinos because of its
adaptability and abundance. Ipomoea
aquatica, or kangkong, has been found
to be helpful in the elimination of fatty
acids lodged in the blood vessels (J.Z.
Galvez-Tan M.D.). This study was
conducted to find the effect of kangkong
on rabbits–which are physiologically and
anatomically similar to humans–and to
verify its potential to reduce the blood
cholesterol levels (BCL) of people
suffering from blood cholesterol-related
ailments such as hypertension. A set of
rabbits was procured and divided into two
groups for a one-month experimentation.
The normal diet of pellets and water was
given to both groups during the first
week. During the second week, the
experimental group received 3 mL of
melted butter daily in addition to the
normal diet. This was followed by a
blood cholesterol count using the
Liebermann-Burchard method. The
rabbits were allowed to rest for a week,
feeding on the normal diet. During the
last week, the experimental rabbits were
fed with 5 mL osterized-kangkong dilute
daily. Again, blood samples were taken
from each rabbit for blood cholesterol
count; the results were analyzed using the
T-test for independent samples. There
was a significant difference between the
blood cholesterol levels of the treated and
untreated rabbits.
INTRODUCTION
Hypertension is a circulatory
disorder in which the blood pressure is
in excess of the normal range for a
person’s age and sex. This condition
proves to be dangerous because it
damages blood vessels in the kidney,
heart, and brain. It may eventually lead
to renal failure, congestive heart failure
and/or cerebrovascular accident or stroke
(Benowitz, 1992). These complications
are the most popular causes of human
mortality today (Van de Graaf and Fox,
1989).
Use of a variety of commercial
drugs is common aside from
nonpharmocologic treatment of the
disease. These drugs, however, are not
always effective in reducing the fatal
complications, because of side effects
(Benowitz, 1992; Tan and Marana 1988),
the use of Ipomoea aquatica, a water
plant growing abundantly in the country,
may be considered to complement the
use of synthetic drugs, not only as a
diuretic
but
also
as
an
anticholesterolemic cure.
This research realized the need to
establish the use of kangkong as a
multiple cure for cholesterol-influenced
hypertension. This may also establish
another potential use of kangkong and
may ultimately help to improve the health
situation in the country.
REVIEW OF RELATED
LITERATURE
The symptoms of hypertension are
headache, dizziness, and nausea, but has
no specific causes. This type of
hypertension is attributed to high salt,
alcohol, and caffeine intake (Wagman,
1993), psychological stress (Benowitz,
1992), and high concentration of
cholesterol in the blood (Guyton, 1991).
free alternative, which is kangkong.
Kangkong, as suggested by Tan and
Marana (1988), could be a good diuretic
and anticholesterolemic medicine.
Establishing this potential is the concern
of this research project.
Various methods have been
developed to cure hypertension,
including dietary restrictions from salt or
sodium, caffeine, alcohol, and solid fats.
Also common are pharmacologic
prescriptions of diuretics (which deplete
the body of sodium), sympathoplegic
agents (which reduce peripheral
resistance), direct vasodilators (which
relaxes vascular smooth muscle), agents
that block the production or actions of
angiotensin (responsible for constricting
vessels) and anti-cholesterolemic drugs
(lowers BCL).
Kangkong is a smooth vine plant
with arrowhead-shaped leaves having
long petioles. It is very abundant in the
country, specifically in standing waters,
fish ponds, and along creeks and muddy
fields. It grows all-year round usually
giving a yield of 40 tons per harvest
(UPSEC, 1980).
Cholesterol is a derivative of fat
(Weiz and Keogh, 1977) which is
synthesized by the body (Britannica, vol.
11, 1977) from fats, mainly classified into
saturated and unsaturated fats. It is a
steroid alcohol which is present in almost
all human and animal tissues, particularly
in the brain and spinal cord, and serves
as a precursor to hormones and bile acids.
The human body contains 200-300 g of
cholesterol while the gallstones may
consist entirely of it. This has been
implicated as being responsible for
circulatory disorders such as
artherosclerosis and hypertension
because it precipitates in the arteries
(Vollhardt, 1987).
C o r re s p o n d i n g ly,
anticholesterolemic drugs are ready for
prescription. All of these drugs, however,
induce adverse body reactions which
include constipation, diarrhea, dyspepsia,
nausea, flatulence, hemorrhoids,
stomatitis, and gastritis (Mosby, 1989).
With this problem in side-effects, this
research considers a natural, side-effect-
Kangkong is not only nutritious,
it also has cholesterol-regulating
components, which contribute to its
effectivity as an anticholesterolemic cure.
Furthermore, Guerrero, as cited by
Quisumbing (1978), claims that
kangkong tops are mildly laxative
(Cajigal, 1992; Quisumbing, 1978).
Being laxative, purgative, and
diuretic (Tan and Marana, 1988),
kangkong may still prove to be an
anticholesterolemic herbal medicine
which could serve as a multiple cure for
hypertension.
MATERIALS AND METHODS
The rabbits were divided into two
groups, each group with five replicates.
The first group served as the control
(normal diet of pellets) while the other
as the experimental (kangkong-fed).
Both groups were allowed to adjust
themselves to the new environment, and
were given pellets and water for
sustenance, for one week.
The control group was given a
restricted diet of pellets and water
throughout the experiment. The
experimental group, on the other hand,
was initially force-fed with melted
commercial butter (3 mL of butter a day
SOPHOMORE
17
to each rabbit) for a duration of one week
to induce high BCL.
Then, the researchers extracted blood
(through intracardial aspiration) from the
rabbits in both groups. The blood was sent
to a hospital technician for cholesterol testing
using Liebermann-Burchard method.
In the course of the blood extraction,
the rabbits were subjected to much physical
stress, so that another week of recovery was
given to all the rabbits.
The experimental group’s diet was
altered after the extraction of blood
samples. Diet consisted of pellets and water
and the kangkong supplement (5 mL a day
to each rabbit for a duration of 10 days).
The kangkong supplement was
prepared by washing, two-minute
boiling, osterizing, and straining. Then
the juice from kangkong was extracted.
The rabbits received the juice using a
syringe.
After feeding the rabbits with
kangkong, the researchers again
extracted blood from them and had the
blood tested.
With the two sets of data from the
tests, the change in the BCL of the rabbits
was computed for. The changes in the
two groups were compared statistically
using the T-test for independent groups.
Using the Liebermann-Burchard
test for cholesterol, the BCL (in
millimoles per liter) for the randomly
selected samples were determined before
and after the experiment. The tests
showed a drop in the BCL of all subjects,
with the control group dropping less
compared to the experimental group’s
BCL.
researchers worked with statistical testing.
There was a significant difference between
the decrease in BCL for the control rabbits
and experimental rabbits.
The difference can be accounted for
by the kind of diet given to each group. All
the rabbits were raised under the same
conditions with the diet as the only exception.
At first, the experimental group received
butter. This resulted in the higher range of
initial BCL count for the group. Then
kangkong was introduced; despite the
difference in starting points, both groups’
BCL ended up in the same range (3.0-3.97
mmole/L). This means that kangkong has
helped in lowering high levels of blood
cholesterol, catching up with the normal
metabolic rate.
In analyzing the change, or the
difference between the initial and final
BCL counts, the experimental group’s
percent drop was, therefore, greater than
that of the control group. And the T-test
showed that it differed great enough to
matter scientifically.
SUMMARY AND CONCLUSION
The kangkong lowered the BCL
faster than the normal rabbit metabolism
(as seen in the minimal decrease in BCL).
The T-test result also calls for future
studies. Kangkong can be developed into
a commercial drug, but it will still have
to go through other researches (such as a
comparative study and a specific
mechanism study).
Kangkong lowers the BCL.
This was established in this research,
using the rabbit’s normal metabolic rate
as the basis.
Guided by this observation, the
18
SOPHOMORE
SELECTED REFERENCES:
Benowitz, Naal. 1992. “Antihypertensive
Agents”. Basic and Clinical
Pharmacology. 5th ed. California, U.S.A.:
Apleton and Lange,
Prentice-Hall International.
Cajigal, Aida. 1992. A Handbook of
Medicinal Plants. (Unpublished)
Henry, John Bernard. 1991. Clinical
Diagnosis and Management
By Laboratory Methods. 18 th ed.
Philadelphia, U.S.A.:
Saunders Company.
W.B.
Tan, J.Z. Galvez and Marana-Tan,
R.R.V. 1988. Fruits and Vegetables
with Medicinal Properties. Quezon
City, Philippines: Service Education
and Research for Community
Health
RESEARCHERS
Gina Arnaldo
Christine Clemente
Sharon Suarez
Junico Visaya
Jose Christopher Mendoza
ADVISER
Mrs. Juanita Cruz
Philippine Science High School
Quezon City
No part of this article may be used or
reproduced in any form whatsoever
without written permission from PSHS,
Diliman, except in the case of brief
citations embodied in scientific articles
and reviews.
This section aims to present various practices and/or beliefs that have gained popularity over the years, and are claimed
by its advocates as grounded on sound scientific principles. They have yet, however, to be formally accepted by the general
scientific community as scientific. For any of it to be considered scientific, controlled and measurable conditions must be able to
replicate the phenomenon or activity. “Pseudo-“ means false and it is best for the public to be made aware of the facts behind
these practices and beliefs.
Pyramid Power
N
ot too long ago, a popular radio announcer espoused
The reputation of the pyramid probably stemmed from people
the power of pyramids over the radio. He even sold
who inferred a relationship between the Egyptian pyramids and the
pyramid-shaped razor blade containers that
process of mummification, a common practice of embalming dead
guaranteed that the blades would never go dull.
royalty at the time. These same people also found it hard to believe
There was also a pyramid-shaped “tent” purportedly to help anyone
that primitive civilizations, like the Egyptians and the Incas of South
who goes inside this object to absorb extraordinary powers. Pyramid
America, could build huge monuments such as the pyramids.
followers also claimed that pyramids had healing power and emanated
spiritual energy.
No scientific evidence has been found to establish any claim
that pyramids can alter, amplify, focus nor create mystical powers.
The fascination for pyramids dates back to 3,000 years when
Pyramid believers thrive in obscure and ambiguous claims. No coded
the dynastic Egyptian civilization built monumental pyramids in the
messages nor esoteric numerology patterns have been found, and
desert. These pyramids were actually burial tombs for Egyptian
no cosmic map has been found in the proportions of pyramids.
royalty. Since then, however, many extraordinary properties were
ascribed to pyramids. In the 1970’s, authors of books on Unidentified
Flying Objects (UFO), such as Erick von Daniken, even postulated
that pyramids were built according to specifications given by
extraterrestrials, in the deserts of Egypt and South America!!
What is a pyramid? It is a polyhedron whose base is a
polygon and whose sides are triangles having a common vertex. In
References:
The Encyclopedia of the Paranormal, edited by Gordon Stein
(Buffalo, NY. Prometheus Books, 1996)
www.skeptics.com.au
the same way that a cube or a cylinder are geometric shapes, a
pyramid is only a visible makeup characteristic of an object.
SOPHOMORE
19
B
I
O
L
O
G
Y
The
Food
Chain:
I
WHO
EATS WHO?
By Raymond A. Oliveros
n a biotic community, there are three
major types of organisms according to
the role each plays - the producers,
consumers, and decomposers.
Producers are those which manufacture their own food
and serve as food for other organisms. Consumers
depend on plants for food. Decomposers, on the other
hand, cause the decay of dead plants and animals.
Consumers are classified into different levels.
Those that eat plants are called herbivores; those that
eat flesh are called carnivores; and those that eat both
plants and flesh are called omnivores. These organisms
interact with one another in a biotic community. An
example of this is an ordinary biotic community in a
field. In a field, the grasses and other green plants
manufacture food. Male mosquitoes suck plant juice
20
SOPHOMORE
while grasshoppers eat leaves. These insects may then
be eaten by a frog and the frog may be eaten by a
snake. The snake, in turn, may be eaten by a hawk and
so on.
In the example, you can see a movement of
materials from one organism to another within the biotic
community. This series of movement of materials is
called a food chain. Several food chains that may be
interlinked with one another constitute the so-called food
web. The food web is divided into two general categories
- the grazing web and the detrital web. The grazing web
begins with green plants, algae, or photosynthesizing
plankton. In this category, materials typically pass from
plants to herbivores to carnivores. On the other hand,
the detrital web begins with organic debris and materials
pass from plant and animal matter to bacteria and fungi,
or decomposers, then to detrital feeders, or detritivores,
and then to their predators, which are carnivores.
A food web can be illustrated through a biotic
community in a forest. In a forest, fungi decompose matter
in a detrital web. It may sprout mushrooms that are
consumed by squirrels, deer, and other animals in a grazing
web. A robin is an omnivore, that is, consumer of both
plants and animals which places it both in the detrital and
grazing web. The robin typically feeds on earthworms which
are detritivores that feed upon decaying leaves. Leaves
are then eaten by caterpillars and other herbivores and
the interlinking of different food chains continues.
The basic characteristic of food chains and food
webs is that they always begin with green plants, the
producers of the community. The green plants are eaten
by herbivores which are considered as the primary
consumers, or first-order consumers. The primary
consumers are then eaten by carnivores which are
classified as the secondary consumers, or second-order
consumers. The secondary consumers are eaten by
higher-order consumers. When all these organisms die,
they are acted upon by worms, bacteria, and other
decomposers. Decomposers release from the dead
organisms substances that can be used again by plants.
The food web can be viewed not only as an
interlinking of chains but also as a series of trophic, or
nutritional levels. Green plants are the primary producers
of food which belong to the first trophic level. Herbivores
belong to the second trophic level while carnivores belong
to the third trophic level. The omnivores belong to the
second and third. Secondary carnivores, which are
predators that feed on predators, belong to the fourth
trophic level. As the trophic level rises, the predators
become fewer, larger, fiercer, and more agile. At the second
and higher levels, decomposers of the available materials
function as herbivores or carnivores depending on whether
their food is plant or animal material.
The food chain, however, adapts to existing
conditions. An example is the case of the killer whales
along the Alaskan coast. Killer whales normally eat seal
and sea lions, whose high fat content is an essential
part of the whale’s diet. But the number of seals and
sea lions in the North Pacific has plunged since 1970,
probably because of commercial fishing and perhaps
global warming. Deprived of their normal diet, the killer
whales began eating sea otters instead. Although only
three killer whales were noted to be eating otters, the
effect is so severe that the animal’s numbers have
dropped by 90 percent. Otters protect kelp beds, an
important fish habitat, so the consequences of this
ecological disruption could be far ranging.
Another example of change in the food web
concerns humans. Organisms that humans did not
usually eat are now part of their regular diet. Insects,
frogs, snakes, and hawks are only some of these
organisms. This may lead to the extinction of these
species. This would disrupt our ecological balance
because the mere loss of one species can actually lead
to many changes of far greater impact, ranging from the
loss of habitats to large-scale alterations in the functions
of those habitats. As the human population climbs, these
cumulative changes will ultimately affect our economies
and our well-being, because natural ecosystems perform
many free-of-charge functions which we take for granted,
such as purification of our wastes, production of
harvestable resources, regulation of our climate, and
restoration of the oxygen that we breathe.
1.
Discuss briefly the interaction of the three major types of
organisms in a biotic community.
2.
Cite some significant changes that have started to occur
in the food web.
3.
How does the rise in human population affect the
environment?
Trophic - concerning nutrition
Kelp - any of several large broad-fronded brown sea weeds
References:
1. Microsoft Encarta Encyclopedia 99
2. Scientific Americans Asks the Experts
3. Integrated Science I
SOPHOMORE
21
GENERAL
SCIENCE
The Delicate
Relationship
Between the
Biosphere and
Mother Earth
O
f the nine planets that revolve around the
sun, the earth is the only one known to
support life. Its atmosphere has the right
mix of gases that allow humans and other
animals to breathe. It has terrestrial and
aquatic resources full of diverse flora and fauna that
ensure the continuity of life.
The portion of the earth that is inhabited by life
is called the biosphere. It consists of all the planet’s
communities and ecosystems, covering the thin layer
of seas, the land to a soil depth of a few metres and the
atmosphere to an altitude of a few kilometres.
The distribution of organisms within the
biosphere follow global and regional patterns that reflect
differences in climate and other abiotic factors in the
environment. Almost all organisms derive their energy
from the sun and must tolerate changes in temperature,
humidity, salinity and light in their environment. Important
abiotic factors are temperature, water, light and wind
(climate); rocks and soil; and periodic disturbances such
as fires, hurricanes, tornadoes and volcanic eruptions.
However, once the balance in the biosphere is
threatened, Mother Earth is put in peril. Whatever
happens in the biosphere affects the entire planet as
well for it is not isolated from the rest of the physical
environment.
As the dominant inhabitants of the planet,
humans have created the largest impact on the
biosphere. Their activities have greatly affected, or
intruded into the dynamics of most ecosystems on earth.
22
SOPHOMORE
An increasing population demands more food and work.
It needs space for agricultural, industrial and residential
purposes. People have found many ways to maximize
the natural resources but at the expense
of Mother Earth and its other inhabitants.
Hotter and longer summers and
other dramatic changes in climate are
some of the more obvious signs of
imbalance in the biosphere. There is too
much gaseous waste in the atmosphere,
such as chloroflourocarbons, carbon
monoxide, and carbon dioxide. The
increase in concentration of carbon
dioxide in particular is expected to raise
global temperature by 3-4 degrees
Celsius by the end of the next century.
A 1.3-degree Celsius rise would make
the planet warmer than at any time in
the past 100,000 years. At the rate warming is happening
now, many organisms are least likely to survive.
Acid rain is part of such climatic changes. Some
of the chemicals from the fumes emitted by vehicles
and factories rise up into the air, mix with water vapor in
the clouds then condense into acid. This acid falls as
rain, damaging the leaves of trees and soaking into the
soil, destroying plants and crops. Acid rain also mixes
with bodies of water, such as lakes and rivers, killing
plants and animals that dwell on them.
Pollution is not limited to the atmosphere. Land
and water also suffer due to harmful human activities.
Many are concerned with its impact on the tropical
rainforest. The forests may appear lush and thriving but
are actually fragile due to nutrient-poor soil and low
densities of individual populations.
The alarming rate of logging and conversion to
other uses of millions of hectares of tropical forests is
putting the biological diversity at risk. Many species of
plants and animals are now in danger of becoming extinct
unless their habitats are preserved and conserved.
Can you imagine living in fiery Mercury or icy
Pluto? If the wanton destruction of Earth continues, you
might as well think of other worlds in other galaxies to
live in.
References:
Campbell, Neil. Biology. California: The Benjamin/Cummings
Publishing Co., Inc.,1996.Childcraft. Illinois: World Book, Inc., 1993.
Vol. 3.
Forming Up Fungi
C
hlorophyll is the green pigment present in plants, which is needed in photosynthesis.
But some plants do not have chlorophyll. These plants are collectively known as
fungi. Included in the group are yeasts, molds, smuts, and mushrooms. This activity
will demonstrate how fungi are formed from different substances.
You will be needing four
specimen–overripe tomato, old bread,
leaves, and plant stems–and four widemouthed glass jars with lid.
PROCEDURE:
1. Sterilize the glass jars by boiling them for at least 5 minutes.
2. Put each of the specimen (tomato, bread, leaves, and stems) in separate
jars.
4. Place the other two jars (tomato and bread) under the sun
for two days. Be sure to cover the jars tightly.
3. Sprinkle the jars containing the stems and the leaves with water before
covering them tightly. Leave these jars in a cool, dark place for two
days.
5. After two days, gather the jars and observe the different
fungal growths.
6. Compare each fungus as to color, texture, and shape.
7. Record your observations.
SOPHOMORE
23
TROPISM
Plants respond or react to outside stimuli in order to grow and survive. In
Biology, this is called tropism. Match each of the environmental factors
with the corresponding type of tropism.
“MOTHER EARTH”
Look for at least ten 3-letter words that you can form
with ‘Mother Earth.’
H A T E O N T E A R
ENVIRONMENTAL FACTORS
__ 1. light
__ 2. gravity
__ 3. touch
__ 4. water
__ 5. chemical
__ 6. current
__ 7. temperature
E T H E R M H E A T
A U E S E C A R T C
R V R A T D T H E R
T B E MO T H P Z Q
TYPE OF TROPISM
a. hydrotropism
b. phototropism
c. geotropism
d. chemotropism
e. thigmotropism
f. thermotropism
g. electrotropism
ALL SYSTEMS GO
Match each body part with the system it belongs to.
A
B
C
D
Rearrange the letters to form the words that correspond to the clues
given.
ELPUS
DIONIE
SELN
NOUGET
this has the same rate as the heartbeat
added to salt to prevent goiter
part of the eye that focuses light on the retina
the organ having numerous taste buds
ACROSS
1 Light brown
4 Fish-eating mammal
8 Six equal square sides
9 Travel of a material
11 Violet root crop
12 Short for Papa
14 Ton per hour (abbr.)
15 Beryllium
16 Upper limb of the human body
17 Errors and omissions (abbr.)
18 One who makes wooden casks
21 Speaks
23 Thulium
25 Source from which valuable material
is extracted
26 An expression
27 That is (abbr.)
28 Neon
29 High temperature
30 Passed away
33 Gaseous emission from burning
34 Planet where we live
35 Me——; rock from outer space
24
__ 1.
__ 2.
__ 3.
__ 4.
__ 5.
__ 6.
__ 7.
digestive system
muscular system
circulatory system
respiratory system
excretory system
reproductive system
nervous system
a.
b.
c.
d.
e.
f.
g.
C R O S S W O R D
1
2
3
4
12
11
15
7
13
10
14
16
17
18
23
19
20
21
22
24
26
25
28
27
30
6
9
8
23
5
31
34
SOPHOMORE
32
29
33
35
kidney
heart
brain
tendons
diaphragm
intestine
ovary
DOWN
1 Hollow cylindrical device
2 —d; in bed
3 Same as 28 across
5 Expeditionary Force (abbr.)
6 Altitude (abbr.)
7 Leap; steady gait
8 Same as 8 across
10 World Health Organization
12 Positively charged particle
13 Unit of current
16 —es; genus of tropical
American nocturnal monkeys
18 Copper
19 H—; at this point
20 Right side (abbr.)
22 Major constituent of living matter
23 Rise and fall of ocean water level
24 —d-; plural of medium
26 Genus of mammals
29 Gradation of color
31 Erbium
32 —ole; a fierce wild dog of India
33 Foot (abbr.)