## Monday, October 3, 2011

### The Mystery Circuit

Consider this circuit

*Assume that voltmeter have infinite resistance and ammeter have very low resistance (negligible)

Scenarios
In the following circuit, determine the reading in all the ammeters in the following scenarios,

A.Switches S1 and S2 are open. (Group 1)
B.Switch S1 is closed and switch S2 is opened. (Group2)
C.Switch S1 is open and switch S2 is closed.(Group 3)
D.Switches S1 and S2 are closed.(Group 4)

Task : Each group to provide the following
Time for this task : 15mins

Groups of 4

1.Post on the blog / board the circuit diagram (according to your scenario)
Include the direction of the current flow.
Detail calculation on the following:
Ammeters readings (A1,A2)

2.Ms Teo will handpick the presenter from each group.
Role of presenter to explain the circuit and how all readings are calculated.

## Friday, August 5, 2011

### Science class Friday

Dear Students,

Please get the following completed.

1. Take 15 mins and complete the following Pre-Quiz on Sound.

Remember to key in the following:
Name / ID (Register Number) /Class
Password: sound

2. Please follow the following link and install software : AudioXplorer ( must be done before next lesson)

You will need this software for the lessons.

Good site on topic Refraction

http://www.cyberphysics.co.uk/topics/light/TIR.htm

On you tube

http://www.youtube.com/user/derekowens
http://www.youtube.com/user/TutorVista#p/search/0/kc2o73FyN3I

Remember to submit your homework.

Ms Teo

## Wednesday, August 3, 2011

### Total Internal Reflection(Justin, Bing Han)

Total Internal Reflection in real life

One way to observe it is while swimming, if one opens their eyes just under the water's surface when the water is calm, the water surface will appear mirror-like.

In addition, it is observed when we critically cut diamond. This is what gives it maximum sparkle.

Another use of total internal reflection would be the transmission of light through optical fibers in fiber optics. The laser beam in the optical fiber has angle of incidence well above the critical angle, and is reflected continuously. A small-diameter glass core is surrounded by a layer of glass cladding, so light undergoes Total Internal Reflection as it is confined within the core. It is used in endoscopes and telecommunications.

Fourth way would be in fingerprinting devices, which uses total internal reflection in order to record an image of a person's fingerprint without the use of ink.

A final way would be on a prismatic binoculars which uses the principle of total internal reflections to get a very clear image.

## Tuesday, August 2, 2011

### Applications on Total Internal Reflection(Nadiah, Casandra, Wei Chern, Niloy)

Application of Total Internal Reflection:

1. Fibre Optics uses in telecommunications:

There are two types of optical fibre used in telecommunications which are the step-index fibre and the graded-index fibre. The step-index fibre is in which the core is made from one type of glass while the outer cladding has a lower refractive index. The graded-index fibre is when the refractive index of the material gradually decreases outwards from the centre of the fibre.

Before optical fibres were invented, telecommunications used copper cables. Some of the problems that people faced while using the copper cables are that due to the copper’s resistance which changed some energy into heat, signals were reduced and had to be re-amplified every few kilometres.

Advantages: Fibre optics used in telecommunications are far more efficient, less bulky and much cheaper. Some examples are local area networks, cable tv and CCTV.

1. Astronomy; the study of stars and galaxies

Fibre optics are used if several stars and galaxies needs to be studied simultaneously to analyse red-shift or spectra. They are bundled together and placed at the focus of a telescope in a block. Hence, each optical fibre received light from parts of the image of the sky.

Advantages: The fibres will lead the light to an instrument where it can studied by translating the light into an electrical signal and feeding the collected data into a computer.

1. Endoscope or Fibroscope:

An endoscope is any instrument used to look inside the body. Thousands of optical fibres are bundled together in an endoscope which is inserted into a human body so that the doctor can 'see' inside. Light can be directed down the fibres even if they are bent, allowing the surgeon to illuminate the area under observation. He can then view this from a television camera linked to a monitor by coherent fibres. Endoscopes are widely used both in medical and vetenary practices. The physics principle on which they are based is total internal reflection within a fibre optic bundle of fibres.

Advantages: Endoscopes can be used to explore and biopsy such areas as the colon and the bronchi of the lungs. By employing miniature television cameras and tiny surgical implements that allow not only exploration but also endoscopic surgery. Through small incisions; such surgery is much less traumatic to the patient than traditional open surgery. Recovery times are shorter, and less anaesthetic is required.

Other applications:

• Bicycle reflectors
• Binoculars/ Periscopes
• Cutting/carving of the diamonds

http://homepage.mac.com/cbakken/obookshelf/total.html

### Applications of Total Internal reflection - Bernard Ng & Azeem

1) A fiber optic is a glass "hair" which is so thin that once light enters one end, it can never strike the inside walls at less than the critical angle. The light undergoes total internal reflection each time it strikes the wall. Only when it reaches the other end is it allowed to exit the fiber. (http://regentsprep.org/Regents/physics/phys04/captotint/default.htm)

2) Diamonds have high refraction index and are cut to sparkle through Total internal reflection.

3) An endoscope is any instrument used to look inside the body. Thousands of optical fibres are bundled together in an endoscope which is inserted into a human body so that the doctor can 'see' inside. Light can be directed down the fibres even if they are bent, allowing the surgeon to illuminate the area under observation (an incoherent bundle is used to do this!). S/he can then view this from a television camera linked to a monitor by coherent fibres.
Usually consisting of a fiber-optic tube attached to a viewing device, endoscopes can be used to explore and biopsy such areas as the colon and the bronchi of the lungs. By employing miniature television cameras and tiny surgical implements thy allow not only exploration but also endoscopic surgery. Through small incisions; such surgery is much less traumatic to the patient than traditional open surgery. Recovery times are shorter, and less anaesthetic is required (sometimes none!). (http://www.cyberphysics.co.uk/topics/light/TIR.htm)

4) Some optical instruments, such as periscopes and binoculars use prisms instead of mirrors to reflect light around corners. This is because mirrors do not reflect light as totally as prisms do (mirrors only reflect about 95% of that reflected by prisms under TIR conditions). Also refraction distortion can result in using a glass fronted mirror. Therefore the image is crisper and brighter. In prismatic binoculars, total internal reflection in prisms is used to extend the path length between objective and eyepiece, effectively `folding' the optical path. This makes them compact and easy to carry. ((http://www.cyberphysics.co.uk/topics/light/TIR.htm)

### Refraction: Internal Reflection

Total Internal Reflection is applied in
1. Rain sensors, for automatic windshield wipers.
2. Spatial filtering of light
3. applied when craving diamonds or stones to ensure that they would reflect light and shine.
4. Fiber optics:
A fiber optic is a glass "hair" which is so thin that once light enters one end, it can never strike the inside walls at less than the critical angle. The light undergoes total internal reflection each time it strikes the wall. Only when it reaches the other end is it allowed to exit the fiber.

Fiber optic cables are used to carry telephone and computer communications. Advantages over electrical wired include:

1. Fiber optics can carry much more information in a much smaller cable.
2. No interference from electromagnet fields result in better connections.
3. No electrical resistance.
4. No hazard of electrocution if cable breaks.
5. Fingerprint devices

References:
1. http://regentsprep.org/Regents/physics/phys04/captotint/default.htm
2.http://en.wikipedia.org/wiki/Total_internal_reflection

Done By:
Casandra, Nadiah, Niloy and Wei Chern

## Monday, August 1, 2011

### Application of Total Internal Reflection

-Optical fibers, which are used in endoscopes and telecommunications.
-Rain sensors to control automatic windscreen/windshield wipers.
-Prismatic binoculars
-Some multi-touch screens total internal in combination with a camera and appropriate softawre to pick up multiple targets.
-Gonioscopy to view the anatomical angle formed between the eye's cornea and iris.
-Gait analysis instrument uses total internal reflection in combination with a high speed camera to capture and analyze footprints of laboratory rodents.
Fingerprinting devices to record and image of a person' fingerprint without the use of ink.
-Flashlight lenses

(done by: Goh Jin Hao, Brandon and Keith)

### uses of total internal refraction, Tan Kein Shuen

Optical Fibers , which in turn can be used in for endoscopes and communicating.
rain sensors, which can be used for automatic windscreens
filtering of light for light sensor wiring
prismatic binoculars uses total internal reflections uses the principle for a higher quality image

## Friday, July 22, 2011

### Powerpoint slides and additional practice questions

Dear Students,

Please note that the powerpoint slides and additional practice questions are up.

Regards,
Karen

## Tuesday, July 19, 2011

### To understand more about mirror reflection

Dear Students,

Many of you have some problem understanding about mirror images. This resource explains that concept pretty well, so do take some time and look into it.

Regards,
Ms Teo

## Tuesday, July 12, 2011

### 12072011 To be completed before Wed class. Homework.

Dear class,

A) On our discussion about light this morning, I have came across a good resource for you to understand just a little more.

This is also a good site for various topics in physics. Good notes and examples.

B) There is a good video that will give you an introduction on reflection.
Reflection video

C) Complete section 1.2.
1) Go through the simulation
2) Through your observation, identify the 5 properties of image formed by mirror.

D) Take 10mins and complete the pre-quiz on the topic
pre-quiz

Get it done please..

Ms Teo

## Friday, July 8, 2011

### Visible Light - Casandra and Niloy

Visible light are the only electromagnetic spectrum that is visible to the human eye. Visible light are infrared waves, visible waves and ultraviolet waves. Visible waves have wavelengths from approximately 390 to 750 nm. Infrared waves have wavelengths more than approximately 750nm. Ultra Violet waves have wavelengths less than approximately 390nm.

Visible Light:  We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. When all the waves are seen together, they make white light. When white light shines through a prism, the white 6 light is broken apart into the colors of the visible light spectrum. Water vapor in the atmosphere can also break apart wavelengths creating a rainbow.

We are able to see objects because it is illuminated by visible light. Whenever we see the sky blue, the grass green or an apple red, it is due to us seeing different wavelengths within the 390 to 750 nm band. Through visible light, reflections and refractions are easily observed.

Spectral Colours

Here is a video about visible light

### Gamma Rays(Nadiah, Bernard & Bing Han)

Introduction :

Among all electromagnetic waves, gamma rays have the shortest wavelengths (less than 0.01 nm), highest frequencies (around 1019 Hz), and, consequently, the highest energies (at least 100 keV). They’re even more energetic compared to their more popular cousins, X-rays. Hence, gamma rays have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. These waves are generated by radioactive atoms and in nuclear explosions. Gamma-rays can kill living cells such as using gamma-rays to kill cancerous cells.

Astronomy:

Gamma-rays travel to us across vast distances of the universe, only to be absorbed by the Earth's atmosphere. Different wavelengths of light penetrate the Earth's atmosphere to different depths. Instruments aboard high-altitude balloons and satellites like the Compton Observatory provide our only view of the gamma-ray sky.

Gamma-rays are the most energetic form of light and are produced by the hottest regions of the universe. They are also produced by such violent events as supernova explosions or the destruction of atoms, and by less dramatic events, such as the decay of radioactive material in space. Things like supernova explosions (the way massive stars die), neutron stars and pulsars, and black holes are all sources of celestial gamma-rays.

This is because most of the gamma radiation observed on the surface of the Earth come from radioactive substances. Due to the wave-particle duality of matter, gamma rays (which are actually electromagnetic waves) are also known as gamma particles. These particles, released during a transition of a radioactive nucleus from a more excited state to a lesser one, bear the energy difference between the two states.

These energy differences are very large, typical of the energies exhibited during interactions in the nucleus. As a consequence, the gamma particles carrying this released energy are very much capable of wreaking havoc on atoms they collide with, rendering the atoms ionized. Thus, like X-rays, gamma rays are considered ionizing radiation.

Gamma particles are actually photons. That means they have zero mass. Despite this, they carry a lot of momentum. Classical physics tells us that this cannot be possible. However, because of the extremely high speeds that these gamma particles have the moment they are released from the nucleus, relativistic effects have to be considered.

One consequence of which is the ability to acquire momentum despite having zero mass. That is why these massless gamma particles can still collide and dislodge loosely attached atom members like electrons. This is precisely the reason why gamma rays, like X-rays, are harmful to the body. Gamma rays can be stopped by high density shielding materials like lead.

Surgery:

Other than for astronomy ,they are used to kill cancer cells without having to resort to difficult surgery. This is so as Gamma rays can kill all living cells.This is called "Radiotherapy", and works because cancer cells can't repair themselves like healthy cells can when damaged by gamma rays.

There's also targeted radiotherapy, where a radioactive substance is used to kill cancer cells - but it's a substance that'll be taken up by a specific part of the body, so the rest of the body only gets a low dose. An example would be using radioactive iodine to treat cancer in the thyroid gland.

Radioactivity is particularly damaging to rapidly dividing cells, such as cancer cells. This also explains why damage is done by radiotherapy to other rapidly dividing cells in the body such as the stomach lining (hence nausea), hair follicles (hair tends to fall out), and a growing foetus (not because of mutations, but simply major damage to the baby's rapidly dividing cells).

Gamma rays are also used to sterilise medical equipment and killed microbes in food so that it will last longer.

### Infrared

Infrared light lies between the visible and microwave portions of the electromagnetic spectrum. Infrared light has a range of wavelengths, just like visible light has wavelengths that range from red light to violet. Humans, at normal body temperature, radiate most strongly in the infrared at a wavelength of about 10 microns. (A micron is the term commonly used in astronomy for a micrometer or one millionth of a meter.)

Infrared is easily generated and doesn't suffer electromagnetic interference, so it is nicely used to communication and control. Some other light emissions could contain infrared as well, and that can interfere in this communication. The sun is an example, since it emits a wide spectrum or radiation.

Infrared Photography is another aspect of infrared. In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared. Wavelengths used for photography range from about 700 nm to about 900 nm. Usually an infrared filter will be used, whereby only infrared (IR) light pass through to the camera, while all or most of the visible light spectrum are being blocked.

INFRARED in Summary

### UV ray

UV Rays (Or Ultraviolet Rays) is a form of energy traveling through space. The most frequently recognized types of energy are heat and light. It is classified under “electromagnetic radiation”.

They travel in waves. Ultraviolet radiation is more energetic than visible radiation and therefore has a shorter wavelength. To be more specific: Ultraviolet rays have a wavelengthbetween approximately 100 nanometers and 400 nanometers whereas visible radiation includes wavelengths between 400 and 780 nanometers.

The major source of this rays is the Sun mainly. 99% of the Sun’s rays are in the form of visible light, ultraviolet rays, and infrared rays (also known as heat). Light enables us to see, and heat keeps us from being cold. However, ultraviolet rays often carry the unfortunate circumstance of containing too much energy. The energy contained in ultraviolet rays is higher, so instead of just causing the molecules to shake, it actually can knock electrons away from the atoms, or causes molecules to split. This results in a change in the chemical structure of the molecule. This change is especially detrimental to living organisms, as it can cause cell damage and deformities by actually mutating its genetic code.

Ultraviolet rays can be subdivided into three different wavelength bands, UV-A, UV-B and UV-C. They are classified on the amount of energy they contain and their effects on biological matter, ranging from UV-C to UV-A, from the most energetic and harmful to the least energetic and harmful.

Thankfully, the UV-C rays are blocked from the Earth’s Surface thanks to the presence of the Ozone Layer which breaks apart the bond of the molecule and absorb the energy. UV-B rays and UV-A have a lower energy level, thus longer wavelength, insufficient enough to split an ozone molecule, some extending down to the Earth’s Surface. Both UV-B and A are detrimental to health, particularly between the hours of 11am and 3pm.

Documentary on UV rays
http://www.youtube.com/watch?v=np-BBJyl-go

### microwaves- by lucas and kein shuen and justin ong

A microwave oven passes (non-ionizing) microwave radiation (at a frequency near 2.45 GHz) through food, causing dielectric heating by absorption of energy in the water, fats, and sugar contained in the food. Microwave ovens became common kitchen appliances in Western countries in the late 1970s, following development of inexpensive cavity magnetrons. Water in the liquid state possesses many molecular interactions which broaden the absorption peak. In the vapor phase, isolated water molecules absorb at around 22 GHz, almost ten times the frequency of the microwave oven.''

Microwaves can be used to transmit power over long distances, and world war two research was done to examine possibilities.

Microwaves also cause microwave burns which are caused by ionizing radiation being abosorbed into organisms(us). they manifest slowly and will show greater signs over a longer period of time,causing major tissue damage if greatly exposed.

the first electromagnetic experiments conducted by Heinrich Hertz in 1886 and also by Marconi used frequencies near the microwave region - some around 500 MHz and some even in the multiple GHz (Gigahertz) region

Justin is a pop fag

### X-ray by Gavin, Nur Nadiah & Yan Jin

Introduction to X-Rays
X-radiation (composed of X-rays) is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers. They are shorter in wavelength than UV rays and longer than gamma rays.

Medical X-rays are a significant source of man-made radiation exposure, accounting for 58% in the United States in 1987, but since most radiation exposure is natural (82%), medical X-rays only account for 10% of total American radiation exposure.

Source: http://en.wikipedia.org/wiki/X-ray

Are X-Rays bad for you?
The problem is that X-rays are a form of ionizing radiation. When normal light hits an atom, it can't change the atom in any significant way. But when an X-ray hits an atom, it can knock electrons off the atom to create an ion, an electrically-charged atom. Free electrons then collide with other atoms to create more ions.

An ion's electrical charge can lead to unnatural chemical reactions inside cells. Among other things, the charge can break DNA chains. A cell with a broken strand of DNA will either die or the DNA will develop a mutation. If a lot of cells die, the body can develop various diseases. If the DNA mutates, a cell may become cancerous, and this cancer may spread. If the mutation is in a sperm or an egg cell, it may lead to birth defects. Because of all these risks, doctors use X-rays sparingly today.

Source: http://health.howstuffworks.com/medicine/tests-treatment/x-ray3.htm

Random facts about X-Rays
• When the wavelengths of light decrease, X-Rays increase in energy
• Smaller wavelengths, and thus have higher energy compared to ultraviolet waves
• X-ray detectors collect photons of X-ray light
• Due to Earth’s thick atmosphere, no X-rays are able to penetrate from outer space to Earth’s surface
• X-rays cannot be felt by us
• Because bones are dense and absorb more X-rays compared to the skin, silhouette of the bones are left on he X-ray film while the skin appears transparent.
• Things in space that emits X-rays, which include black holes, neutron stars, binary star systems, supernova remnants, stars, the Sun and some comets.

Source: http://science.hq.nasa.gov/kids/imagers/ems/xrays.html

### Radio waves

Radio waves have the longest wavelengths in the electromagnetic spectrum. These waves can be longer than a football field or as short as a football. Radio waves do more than just bring music to your radio. They also carry signals for your television and cellular phones.The antennae on your television set receive the signal, in the form of electromagnetic waves, that is broadcasted from the television station. It is displayed on your television screen.

Cable companies have antennae or dishes which receive waves broadcasted from your local TV stations. The signal is then sent through a cable to your house.

Radio frequency energy has also been used in medical treatments, generally for minimally invasive surgeries and coagulation, including the treatment of sleep apnea Magnetic resonance imaging uses radio frequency waves to generate images of the human body.

source:http://en.wikipedia.org/wiki/Radio_waves
http://science.hq.nasa.gov/kids/imagers/ems/radio.html

## Wednesday, July 6, 2011

### Classwork for 06072011

Dear Students,

Complete the 2 excerise below:
1) Go through the following simulation on EM spectrum.
http://www.glencoe.com/sites/common_assets/science/virtual_labs/CT05/CT05.html

2) Watch the video to understand more about the spectrum
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/radiation/the_electromagnetic_spectrumact.shtml

## Tuesday, February 15, 2011

### Leaf Structures & Functions (with online quiz)

1. http://www.enchantedlearning.com/subjects/plants/leaf/ (Online Readings)

## Sunday, January 16, 2011

### Biodiversity 5 - An Organism's World (Abiotic factors in an environment)

Group work:
Conduct online research to find the out how organisms live in different environment with different abiotic factors.

1.             How do mangrove plants such as Avicennia obtain oxygen when their roots are buried in the mud?
2.             How are xerophytes adapted to survive prolonged drought?
3.             What do polar bears survive in regions where temperatures are constantly freezing?
4.             How do deep-sea anglerfish locate its prey in darkness?
5.             Why can’t a saltwater fish survive in freshwater aquarium? What are the differences in pH between seawater and freshwater ponds?

- Post your findings in the class Environmental Science blog.
- Include pictures to elaborate or support your findings.
- Students are to review each group findings.

What is the key understanding of this lesson?

## Friday, January 14, 2011

### Biodiversity 4 - An organism's world

As a group, watch the video and answer the questions in the Google spreadsheet below.
Note: You are required to sign in with your s2010.sst.edu.sg account.
https://spreadsheets0.google.com/a/s2010.sst.edu.sg/ccc?key=t5yKwcDVl2Eq-Y4yhhiFMOg&hl=en#gid=0

## Wednesday, January 12, 2011

### Reflection- Casandra Ong

1. Biodiversity is the variety of life forms in the ecosystem and on the planet.

2. Biodiversity is important for us as without biodiversity there will be an imbalance in the food web, which will lead to severe extinction. If there is no prey for the predator, the predator will have no food, hence causing extinction.

3. I learnt the how living things were classified, for example using taxonomy and the 5 kingdoms. I also learnt how they are being classified, such as what kind of characteristics they ought to have to be classified as that. I also learnt how the 5 kingdoms came about.

## Tuesday, January 11, 2011

### Reflection

1) What is biodiversity?
It is a variety of living forms in the eco-system.

2) In one or two sentences, explain why is biodiversity is important to us.
Biodiversity is important to us as it balance the population size and makes sure that none of the species becomes extinct, Without it, the population will be imbalance and most of the species will become extinct.

3) What is the key understanding of this lesson?
The key understanding of this lesson is how we classify the various species into the different kingdoms by judging through their structural characteristics.

Niloy Faiyaz

### Task 4: Reflection

#1. What is biodiversity?
The variety of different lives on Earth.

#2. In one or two sentences, explain why biodiversity is important to us.
It provides us with a variety of natural resources such as food. It also balances the ecosystem.

#3. What is the key understanding of this lesson?"
I have learnt how to clearly classify the different types of lives into the 5 different kingdoms.

Khim Tan (05)

### Task 4: Reflection Exercise

What is biodiversity?

Biodiversity is the variability of all living organisms (including animal and plant species) of the genes of all these organisms, and the terrestrial, aquatic and marine ecosystems.

In one or two sentences, explain why biodiversity is important to us.

With every breath we take, we consume oxygen produced by forests and seas.  Every mouthful of food has been living material that relied on soil, microbes and plants to grow thus it provides us with the basics of life.

What is the key understanding of this lesson?

All living things of Earth used to be on its own but slowly it is being classified by the different kingdoms of life from 2 basic kingdoms of Plantae and Animalia till now the 5 Kingdoms, Animalia, Plantae, Monera, Protista and Fungi.

Looi Wei Chern (15)
S2-03

### Task 4 Reflection

What is biodiversity?
Biodiversity is the variation of life forms within a given ecosystem or an entire planet.

In one or two sentences, explain why biodiversity is important to us.
It is important as it helps to balance the ecosystem like the food chain as without the prey, the predator would soon become extinct

What is the key understanding this lesson?

The key understanding was of how and which groups the different organisms were classified into no matter how similar they looked like to another group. I also learned a little bit about the different groups.

### Reflection

1. What is biodiversity?

Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet.

2. In one or two sentences, explain why biodiversity is important to us.

Biodiversity brings enormous benefits to mankind from direct harvesting of plants and animals for food, medicine, fuel, construction materials, and other uses to aesthetic, cultural, recreational and research values.

3. What is the key understanding of this lesson?

We have learnt how the classify the creatures of the world into five different kingdoms

Azeem Arshad Vasanwala
S2-03

### Reflection

Biodiversity is the wide range of life forms in an ecosystem.

Biodiversity is important as without it, there will be an imbalance in the ecosystem and it ensures the continuity of one's kind so that it will not become extinct, basically, to ensure the continuation of the food chain or web.

I have learnt the different kingdoms and how to classify them based on the different levels of taxanomy. I have also learnt on how they are classified based on their structural characteristics and behavioural characteristics. Besides that, i have learnt on scientific name came about and how to write it correctly.

-Nadiah

### Reflection

Biodiversity is the diverse variety of life all around us. Biodiversity is important as without it, there may be imbalance in our ecosystem and the food web. Without it, there may not be multiple ecosystems and earth may lose its beauty and uniqueness.
My key understanding of the lesson was the history of the modern classification system, how organisms are classified and the different characteristics of different groups of organisms.

Gregory Chew

## Monday, January 10, 2011

### Pisces

Pisces are part of Fish

1) They are any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills

2) They are the flesh of fish used as food

Sources: http://www.audioenglish.net/dictionary/fish.htm

### Monera

Monera are about 1 micrometer in size and complex as living molecules. An example of Monera are bacteria. The cell structure of Monera lacks nuclei and many other organelles.

The source of nutrition for these organisms is usually photosynthesis or chemosynthesis.

The Monera characteristics also include the shape of the cell that includes round (cocci), rod-like (bacilli) or spiral (spirochetes or spirilla).Monera reproduce asexually through binary fission or sexually by conjugation. The process of circulation and digestion is carried out through diffusion.Most of the Monorans can survive harsh environment by producing spore coa.

## Sunday, January 9, 2011

### Group 4 - Myriapoda

Myriapoda consist of millipedes, centipedes and others. Although their name suggests they have myriad (10,000) legs, they range from having over 750 legs to having fewer than ten legs. Myriapods have a single pair of antennae and, in most cases, simple eyes. The mouthparts lie on the underside of the head, with an "epistome" and labrum forming the upper lip, and a pair of maxillae forming the lower lip. Myriapods breathe through spiracles that connect to a tracheal system similar to that of insects.

### Reptiles

http://www.animaldanger.com/australia.php
Reptiles fall under the Class Reptilia. They are separated by 4 orders:Crocodillia(the crocodylians) the Sphenodonta (tuatara), Squamata(lizards and snakes) and Chelonia(turtles). Most reptiles have scales,have lungs to breathe and are all cold-blooded.They also lay eggs to reproduce,although certain species do give birth to young alive.The reptile eggs and most of the times buried underground to wait for it to hatch.They are all vertebrates which means they have backbones.

## Saturday, January 8, 2011

### Flatworms-Group 3-Niloy Faiyaz

source: http://www.diverosa.com/Puerto%20Galera/FPG-13%20Racing%20Stripe%20Flatworm,%20Pseudoceros%20bifurcus.jpg

The flatworms are also known in scientific literature as Platyhelminthes. They are the simplest form of the worm groups. There are about 20,000 species in this group. They are found in many places mainly in marine and fresh water. The can be harmful too. They are considered as prototypes on having developed such innovations as bilateral symmetry, a head, tail, and three germinal tissue layers which are stinging celled animals, comb-jellies, only have two. These simple soft-bodied animals use their skin to breath by diffusion through and only have one body opening, the mouth serving also as an anus. These are also important species to humans directly and indirectly through their negative interactions with food and ornamental animal life.

## Friday, January 7, 2011

### Animalia-Sponges

Animalia (Sponges)

1.Sponges are known as Phylum Porifera.
2.Phylum Porifera are the most primitive group of animals.
3.They are aquatic.
- most groups are found in salt water
- only one group is found in freshwater
4.Most are filter feeders.
5.Only one genus is carnivorous.
6.Adults are non-moving(sessile)
7.They are Asymmetric or radially symmetric in shape.

Information Adapted from:
http://iweb.tntech.edu/cabrown/Zoology/Zoo%20Lectures/Porifera1110.pdf

### Mammals

Mammals have several unique characteristics that differentiate them from other animals.
Most mammals have hair, or fur, covering their body.
They are also capable of regulating their body temperature. These allow the mammal to maintain a constant body temperature, regardless of the environmental temperature.
One other difference is that mammals give birth to young alive, and the female mammals produce milk to feed their young.
Most mammals walk on 4 legs, with only the humans walking upright on 2 legs. Aquatic mammals have flippers, or fins, for swimming rather than legs.

### Amphibians

The class Amphibia includes frogs, toads, salamanders, newts and caecilians. Amphibians are characterized by a glandular skin without external scales, by gills during development (and in adulthood in some), and by eggs that may have jelly coats. A amphibian reproduces sexually. The eggs are fertilized outside of the mother's body. The mother lays the eggs which are in a jellylike layer. The father immediately comes by and fertilizes them. The frog's eggs are black and white. The young frog is called a tadpole and it hangs on to plants. Young amphibians tend to resemble small fish. A amphibian is cold blooded so its body temperature is the same as its surrounding environment. A amphibian has a thin skin that is moist.
Source:

### Angiosperms- Group 2 [Casandra, Nadiah, Khim]

Angiosperms (Flowering Plants)

Angiosperms are the most diverse group of land plants.
Angiosperms can be found in both aquatic and terrestrial habitats.
Angiosperms are like gymnosperms, which reproduce seeds.
Angiosperms produces seeds like Gymnosperms
Angiosperms are different from Gymnosperms such that the seeds of Angiosperms are not exposed, like the ones of Gymnosperms, and are contained in fruits.

Information Adapted from :
https://www.msu.edu/course/plb/106/gymnosandangios_s06.doc
http://en.wikipedia.org/wiki/Flowering_plant

### Mosses (Group 1)

Key characteristics of mosses:
• Can be classified according to tissue structure (Non Vascular)
• Can be classified according to seed structure
• Can be classified according to stature

(Azeem)

### Ferns (Group 1)

Key Characteristics of ferns
• Can be spore producing
• Are asexual
• Consist of
• Roots
• Stems
• Fronds(Leaves)
(Azeem)

### Grp 4 - Echinoderm

Echinoderm

Echinoderms (Phylum Echinodermata) are a phylum of marine animals.The phylum contains about 7,000 living species including sea cucumbers, sea urchins and starfish. The echinoderms are important both biologically and geologically: biologically because few other groupings are so abundant in the biotic desert of the deep sea, as well as the shallower oceans, and geologically as their ossified skeletons are major contributors to many limestone formations, and can provide valuable clues as to the geological environment. Many echinoderms have remarkable powers of regeneration. Some starfish are capable of regenerating lost arms. In some cases, lost arms have been observed to regenerate a second complete sea star. Sea cucumbers often discharge parts of their internal organs if they perceive danger. The discharged organs and tissues are quickly regenerated. Sea urchins are constantly losing their spines through damage — all parts are replaceable. Some starfish populations can reproduce entirely asexually purely by the shedding of arms for long periods of time.

### Insecta

Insectas have a chitinous exoskeleton, a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes, and two antennae. They are one of the most diverse group of animals on the planet and include more than a million species and represent more than half of all known living organisms. Insects move about by walking, flying or occasionally sinking and swimming at the same time.

picture taken from:http://en.wikipedia.org/wiki/Insect

### Key Characteristics of Ferns

- Non-flowering plants
- A frond is the leaf of the fern
- Fronds attached to a rhizome(specialized, root-like stem) by a stalk(aka stipe)
- Can grow till ≥ 18m in height and have leaves ≥ 5m long
- Reproduce by spores
- Usually found in trees

Source:
http://science.jrank.org/pages/2679/Ferns-General-characteristics.html
http://www.britannica.com/EBchecked/topic/204819/fern/49908/General-features

Group 2:
Casandra Ong
Nadiah Shaharuddin
Khim Tan

### Arachnids

Almost all adult arachnids have eight legs, and arachnids may be easily distinguished from insects by this fact, since insects have six legs. However, arachnids also have two further pairs of appendages that have become adapted for feeding, defense, and sensory perception.

### Group 2-Cnidaria(Animalia)

The Cnidaria as a group of animals are well known to many people under their common names, Sea Anemones, Corals and Jellyfish are all Cnidarians. They are linked together by their carnivorous feeding habits their simple anatomical design and the possession of nematocysts, though one species of Ctenophora possesses nematocysts as well.

Characteristics of Cnidaria(Animalia)
1) Radially Symmetrical.
2)Body multicellular, few tissues, some organelles.
3)Body contains an internal cavity and a mouth.
4)Two different forms exist, medusa and polyp
5)Reproduction is asexual or sexual.
6)Has a simple net like nervous system.
7)Has a distinct larval stage which is planktonic.
8)Lives in aquatic environments, mostly marine.
9)Mostly carnivorous otherwise filter feeders.
10)May have a minimal skeleton of chiton or calcium carbonate.

Source: http://www.earthlife.net/inverts/cnidaria.html