Chapter 1 The World Through Our Senses

Chapter 1 The World Through Our Senses

1.1 Sensory Organs

1. Humans have five sensory organs.

2. They are eye, ear, nose, tongue and skin.

3. The sensory organs enable an organism to detect changes in the surrounding.

4. Sense is the ability of the sensory organ to detect a stimulus.

5. Our five senses are the sense of sight, hearing, touch, taste and smell.

6. A stimulus is a change in the environment that produces a reaction in a living organism.

7. Examples of stimulus are light, sound, heat, taste, smell.

Relation between sensory organ, senses and stimulus

Sensory organs	Senses	Stimulus
Eye	Sight	Light
Ear	Hearing	Sound
Nose	Smell	Smells (Chemicals in the air)
Tongue	Taste	Sweet, sour, bitter, salty (Chemicals in food)
Skin	Touch	Pain, pressure, heat, cold, touch

Stimulus to response

1. Response is the way an organism reacts to a stimulus.

2. The pathway from stimulus to response is shown as below:

3. Stimulus Sensory organ Nerves Brain Nerves Effectors Response

4. A stimulus will stimulate the sensory organ to produce nerve impulses.

5. These impulses are sent to the brain through the nerves.

6. The brain receives the messages and interprets them.

7. The brain then decides what to do and sends out nerve impulses through the nerve to effectors.

8. Effectors are parts of the body that carry out responses. For example, muscles or organs.

9. A response is a reaction produced in answer to a stimulus.

10. The brain controls all the actions and responses of the body.

SELF ACCESS LEARNING (SAL) FORM 1

Objective: To understand the steps in scientific investigation

NOTE

1.3 Steps in a Scientific Investigation

1 The steps for acquiring scientific knowledge are summarized below:

i)Identifying the problem
ii)Proposing a hypothesis
iii)Controlling variables:
Ø Manipulated
Ø Responding
Ø Constant

iv)Collecting data
v)Analysing and interpreting data
vi)Reporting
vii)Forming conclusion
viii)Planning an investigation
(experiment)


Procedure:
1. For objective questions each question is followed by four options, A, B, C and D. Choose the correct answer.


OBJECTIVE QUESTIONS

1. The steps given below form the procedure of a pendulum swings experiment.
K – To make a rational conclusion
L – To gather and record accurate data
M – To make accurate observations
N – To analyse and interpret data

Which of the following is the correct order of the steps in the above procedure of a pendulum swings experiment?
A K -> L -> M -> N B N -> M -> L -> K
C L -> M -> K -> N D M -> L -> N -> K


2. Which of the following questions might be a problem statement for a scientific investigation?
A What can be done to persuade people to recycle waste?
B Can plants make food when placed under a fluorescent light?
C How can we change the religious beliefs of others?
D How many odd numbers are there between 1 and 100?


3. J, K, L and M are among the steps involved in a scientific investigation.

J : Forming hypothesis
K : Carrying out experiment
L : Making conclusion
M : Planning experiment

A J, M, K, L B J, M, L, K
C M, J, K, L D M, K , J, L


4. What is fixed variable?
A A variable that is being controlled
B A variable that has a constant value
C A variable that changes periodically
D A variable that is dependent on other variables

STRUCTURED QUESTIONS

1. An experiment is carried out to investigate the relationship between the length of the pendulum and the period of oscillation.

a) State a hypothesis for the investigation.
_________________________________________________________________
[1 mark]
b) State the following variables in the experiment.
(i) Manipulated : _____________________________________________
(ii) Responding : _____________________________________________
(iii) Constant : _____________________________________________
[3 mark]


2. What conclusion can be made from the results?
__________________________________________________________________
__________________________________________________________________
[1 mark]



e) State one reason why the experiment is repeated three times for each length of the pendulum.
__________________________________________________________________
__________________________________________________________________
[1 mark]

Food Deficiency Diseases

KWASHIORKOR
Kwashiorkor is an acute form of childhood protein malnutrition . Symptoms of kwashiorkor are swelling of the feet, distended abdomen, an enlarged liver with fatty infiltrates, thinning hair and loss of teeth.



MARASMUS
Marasmus is a form of severe protein malnutrition. A child with marasmus looks emaciated. Body weight may be reduced to less than 80% of the normal weight for that height

BERI-BERI
Beri-beri is a nervous system ailment caused by a deficiency of vitamin B in the diet. Symptoms of beri-beri include severe lethargy and fatigue, together with complications affecting the cardiovascular, nervous, muscular, and gastrointestinal systems.




PELLAGRA
Pellagra is a vitamin deficiency disease most commonly caused by vitamin B in the diet.

Pellagra sufferer with red skin lesions





SCURVY
Scurvy is a disease resulting from a deficiency of vitamin C. Scurvy sufferer with gums bleed easily.





RICKETS
Rickets is a softening of bones in children potentially leading to fractures and deformity. The predominant cause is a vitamin D deficiency, but lack of adequate calcium in the diet may also lead to rickets.


Radiograph of a two-year old rickets sufferer




GOITRE
A goitre or goiter is a swelling in the thyroid gland which can lead to a swelling of the neck or larynx (voice box). Goitre usually occurs when the thyroid gland is not functioning properly. The most common cause for goitre is iodine deficiency.




FIBRE
Constipation, is a condition of the digestive system in which a person (or animal) experiences hard feces that are difficult to expel.

Types 1 and 2 on the Bristol Stool Chart indicate constipation





Source: Wikipedia

Perlawanan Persahabatan SGGS dan MI

Detik sejarah 31 Mac 2010, pertama kali diadakan perlawanan persahabatan antara SGGS dan SMK Mutiara Impian (MI) di padang bola jaring SGGS..Jutaan terima kasih kepada MI kerana sudi datang ke sekolah ini..Walaupun hampa keputusannya tetapi semangat SGGS terus membara.. Yeahhh..Don't give up girls.. our SGGS netball akan maju akan datang!!!....

Gambar bersama pemain SGGS dan MI

Interactions among Organisms

1. Competition
Occurs frequently between many species. Plants vie with other plants for air, soil, water, light, and space. Different animals may need the same food, water, or space. More or less intense depending on conditions. One species wins, one may die, or each adapts.

2. Symbiosis

Symbiosis means different organisms living together in close association. The major kinds of symbiosis relationship include commensalism, mutualism and parasitism.

a) Commensalism
Commensalism is a symbiotic relationship that benefits one species and neither hurts nor helps the other. For example, epiphytes are plants that grow on the branches of other plants. In general, the host plant is unharmed, while the epiphyte that grows on it benefits.

b)Mutualism
Mutualism is a symbiotic relationship among organisms in which both species benefit. Example involves ants and aphids. Aphids also called greenflies are small insects that suck fluids from the phloem of living plants with their piercing mouthparts. They extract a certain amount of nutrients but they excrete much of it in an altered form through their anus. The ants carry the aphids to new plants, and the aphids excretion consume as the food for ants.

c) Parasitism
Parasitism may be regarded as a special form of symbiosis in which parasite or predator is much smaller than the prey. Parasitism is harmful to the prey organism and beneficial to the parasite. In parasitism, one organism serves as a host to another organism and usually to the host’s disadvantage. Flea bites on a human is an example of parasitism (the flea as parasite to the human host in this case).


3. saprophyte

Is the organism that feeds on dead or decaying tissues of other organisms. It is in the class of detrivores. In food webs, detritivores generally play the role of decomposers. Detritivores are often eaten by consumers and therefore commonly play important roles as recyclers in ecosystem.

Kemenangan Pasukan Bola Jaring SGGS

Hooorayyyy....Tahniah kepada Pasukan Bola Jaring 18TKB SGGS yang telah menjadi Johan Peringkat Zon Air Itam semasa pertandingan bola jaring pada 22 Mac 2010 di PKSW, Georgetown..Semoga sentiasa berjaya dan bersedia untuk pertandingan peringkat negeri..

Gambar-gambar detik kemenangan pasukan bola jaring SGGS

PEKA Science

You are required to do experiment 1.23(Longman Science Process Skills Form 2)

Example PEKA Report:

Topic : Response of plants towards Light

Aim : To study the response of the shoots of plants towards light

Hypothesis : The shoots of plants grow towards light

Variables :
a) is kept constant : Type of seeds
b) is manipulated : Direction of light
c) responds : Response of the shoot

Materials and Apparatus : Green bean seeds, box, wet cotton, evaporating dish

Procedures:
1) Two days before starting the experiment, three to five green bean seeds are left to germinate on wet cotton wool in two evaporating dishes.
2) Evaporating dish P containing green bean seedlings is placed under sunlight.
3) Evaporating dish Q with its seedlings is placed in a box which had a hole at the top and also left under the sun
4) The apparatus are left for three days. Observations are recorded and drawn at the end of the experiment.

Observation:
(draw the figures in blank A4 paper)

Analysis:
(copy and answer the questions)

Conclusions:
The shoot of a plant grow towards light