CSS Forums Tuesday, October 21, 2014
06:33 PM (GMT +5)
 
 
Home   Beginner's Guide   Rules   Syllabus   Past Papers   CSP Members  

Go Back   CSS Forums > CSS Compulsory Subjects > Everyday Science > Everyday Science Notes

Everyday Science Notes Everyday Science Notes here

Reply Share Thread: Submit Thread to Facebook Facebook     Submit Thread to Twitter Twitter     Submit Thread to Google+ Google+    
 
LinkBack Thread Tools Search this Thread
  #1  
Old Sunday, January 17, 2010
Saqib Riaz's Avatar
Senior Member
 
Join Date: Apr 2009
Location: Rawalpindi
Posts: 723
Thanks: 440
Thanked 934 Times in 470 Posts
Saqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really nice
Smile EDS Prepratory Notes

Reflection of Light:

When a beam of light travelling in a straight line homogeneous medium falls on the boundry of another medium, then a part of it bounces back from there, this bouncing back of the light is called the reflection of light.



Dependence of reflection of light
The amount of light reflected from the surface of another medium depends on
  • Nature of the medium
  • Smoothness of the medium.

Spherical Mirrors
A spherical mirror is portion o the reflecting surface of a hollow sphere.
Types
  • Concave Mirror
  • Convex Mirror
  1. Concave Mirror: If the Inner surface of the spherical mirror is reflecting, then it is called a concave mirror.
  2. Convex Mirror: If the outer surface of a spherical mirror is reflecting, then it is called the convex mirror.

SOME IMPORTANT DEFINATIONS
  1. Centre of curvature: The centre of the hollow sphere of which mirror is a part, is called its centre of curvature.
  2. Radius of Curvature:The radius of the hollow sphere of which mirror is a part, is called Radius of curvature.
  3. Aperture: The front section of a spherical mirror is circular one and its diameter is called aperture.
  4. Pole:The central point of a mirror is called its pole.
  5. Principal Axis:The line joining the pole of the mirror and centre of curvature is called principle axis of the mirror.
  6. Principle Focus:Rays of light parrallel to principal axis after reflection from a concave mirror converges to a point is called principal focus of the mirror.
  7. Real and Virtual Focus:The reays of light parrallel to principal axis is realy pass through the principal focus then it is known as real focus.If the rays of light parallel to principal axis do not really pass through the principal focus , but seems through it then this is known as virtual focus.
  8. Focal Length :The distance between principal focus and pole of the mirror s called its focal length.
    • Focal Length of concave mirror is positive
    • Focal length of convex mirror is negative.

USES OF SPHERICAL MIRRORS

CONCAVE MIRRORS
  1. Concave Mirrors are used as shaving mirrors.
  2. Concave mirrors are used as magnifiers
  3. Concave mirrors are used to throw light on the slides of microscopeto view it more clearly.
  4. These mirrors are used in search light and head lights
  5. These mirrors are also used by doctors in their instruments for the examination of eye,nose ears and throat.
  6. Some developed countries use giant mirrors in their huge telescopes.

CONCAVE MIRRORS
  1. Convex Mirrors are used in motorcycles and automobiles to see the rear view.
  2. Convex mirros are used in huge shopping centres for security purposes
  3. Convex mirrors are used on the blind turns anddangerous turns.

Quote:
The speed of light is 3x10 power 8 m/s
REFRACTION OF LIGHT

The bending of light when it enters from one medium to another is called refraction of light.

LAWS OF REFRACTION
There are two laws of refraction of light.
  • The incident ray, the refracted ray and the normal at the point of incidence all are in the same ratio.
  • The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant for a given pair of media.

CONDITION FOR REFRACTION
  1. When a ray pf light passes from rare to denser medium, it bendds forward the normal.
  2. When a ray of light passes from denser to rare medium, it bends away from the normal.

APPLCATIONS
Refraction of light may have given us false visual impression , but it does have many useful applications .Lenses are used in magnifying glasses,spactacles,microscopes, telescopes and overhead light rays passing through them produce the required images.

APPARENT AND REAL DEPTH
When we view an object at the bottom of a swimming pool, the object appears closer to the surface. This aparent depth is caused by refraction of light. It occurs due to fact the rays from an object under water do not travel straight to the eye but are refracted away from the normal as they leave the water surface. When these rays are produced backward, they meet and their images is formed so that the observer sees the object as that it were at the point of formation of tages.

APPARENT DEPTH
The distance of image from the surface of the water is called apparent depth.

REAL DEPTH
The distance of object from the surface of water is called real depth.

TOTAL INTERNAL REFLECTION

When a ray of light from denser medium enters a rare medium in such a way that the angle of incidence is greater than the critical , then they reflects totally inside and does not emerges out from the denser medium.This phenomenon is called Total internal reflection
When the value of angle s of incidence becomes greater than the criticale angles the rays does not pass into the second medium i.e the ray of light no longer suffer refraction but totally reflected back in the danser medium obeying laws of reflection.

Conditions for total internal reflection
  1. The ray of light should travel from a denser to a rare medium.
  2. The angle of incidence should be greater than the critical angle.

Dispersion of light
The phenom of splitting of white light into its colours is called dispersion of light.

The refraction of light depends on their wavelength.Since the sunlight consists of different colours the waves of different wavelength obtained. Therefore when light passes through a prism then the wave of different wavelength deviate on different paths due to dispersion of light.
The band of colours which is seen on the the screen due to passage of sunlight through the prism is known as solar spectrum..

RAINBOWS
An arc of spectral colours, which appears in the sky after the rainfall is called rainbow.

How rainbow is formed?
Rainbow is solar spectrum produced due to dispersion of light. After the rainfall, innumerable droplet of water remain suspended high up in the air. When sunrays fall on these droplets each droplet behaves likes a prism and light rays enterig, the droplets suffers refraction and total internal reflection. Since these rays are white light, they split into seven colurs.

CONDITIOn
Rainbow is the most beutifu and colourful natural ph whcih can be seen on the sky.
The viewers can see the rainbow when the sun is at the back of the observer.
When sunrays fall obliquely.
Rainbow can be seen in the morning or in evening.

TYPES OF RAINBOW

1.Primary Rainbow
Such rainbow has brightest colours and is easily visible .
Characteristis
  • In primary Rainbow, the rays fro the sun suffer only one total internal reflection in rain droplet.
  • It has brightest colours and is easily visible
  • It has red colour on its outer edge and voilet colours on its inner edge.
  • In primary rainbow the colour are in the order of red ,orange ,yellow ,green, blue, indigo, and voilet.

2.Secondary Rainbow
Such Rainbow which is fainter than primary and is seldom visible called secondary rainbow.

Characteristis
  • In Secondary Rainbow, the rays fro the sun suffer double total internal reflection in rain droplet.
  • It has faintest colours and is seldomvisible
  • It has voilet colour on its outer edge and red colours on its inner edge.
  • In primary rainbow the colour are in the order of voilet , indigo,blue, green,yellow, orange, red

Continue
Note:If there is any error(s) kindly correct me.
__________________
Always do what you are afraid to do
Saqib Riaz(TIPO KHAN)
Reply With Quote
The Following 6 Users Say Thank You to Saqib Riaz For This Useful Post:
BALOCHISTAN (Saturday, September 29, 2012), fidamah (Sunday, January 17, 2010), Honey123 (Sunday, January 17, 2010), MAHIKAN (Sunday, January 17, 2010), nageen (Monday, January 18, 2010), taim231 (Wednesday, November 10, 2010)
  #2  
Old Sunday, January 17, 2010
Junior Member
 
Join Date: Jan 2009
Location: The back of beyond
Posts: 25
Thanks: 8
Thanked 12 Times in 8 Posts
saima muzaffar is on a distinguished road
Default

Really good try,,, kindly make such effort for computer nd solar system. Thank you
Reply With Quote
The Following User Says Thank You to saima muzaffar For This Useful Post:
Saqib Riaz (Sunday, January 17, 2010)
  #3  
Old Sunday, January 17, 2010
Saqib Riaz's Avatar
Senior Member
 
Join Date: Apr 2009
Location: Rawalpindi
Posts: 723
Thanks: 440
Thanked 934 Times in 470 Posts
Saqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really nice
Default Atomic And Nucleur Physics

Atomic And Nucleur Physics

Structure of an Atom

An Atom consists of two parts
i.Nucleus
ii.Extra Nucleur space

i.Nucleus
Nucleus occupies only a small fraction of the total volume of an atom and is at the centre of an atom. The two main particles of nucleus are the positively charge proton and neutron with no charge. The mass of both is almost equal and is 1.67 x 10-27 kg.

ii.Extra Nucleur Space

In this space negatively charged particlle (electron)moves around the nucleus in orbits of various shape. The mass of an electron is 9.1 x 10-31 kg

ATOMIC NUMBER

The number of protons in the nucleus of an atom is called atomic number. It is denoted'Z'. It is also called charged number.

MASS NUMBER

The total number of protons and electrons in the nucleus of an atom is called mass number. It is denoted by 'A'

The no's of nuetron"N" present in nucleus is given by.

Quote:
N=(A-Z)
If the atomic number of an atom "X" is A and atomic mass number is Z then this atom is represented by the symbol "

wch is called the nucllide.
For example there is only one proton in the nucleus of H atom so its atomic no is 1 and atomic mass number is also 1 .

ISOTOPES

Isotopes are those elements whose atomic numbers are same but their mass number are different.
For Example Hydrogen has three aisotopes represented by

Quote:
Isotopes are neutral atom contains same no of protons and electrons
DIFFERENCE BETWEEN ATOMIC NUMBER AND ATOMIC MASS NUMBER

TOMIC NUMBER
  1. It is the number of protons in the nucleus of an atom.
  2. It is also called cahrge number.
  3. It is identity of an atom.No two elemenets can have same atomic number.
  4. It is denoted by "Z".
  5. It is equal to numbers of orbiting electron in a neutral atom.
  6. It is always less than atomic mass number for an element.

ATOMIC MASS NUMBER
  1. It is the sum of the numbers of proton and neutron in a nucleus.
  2. It is also termed as mass number.
  3. Different isotopes of two elements may have same atomic mass number.
  4. It is denoted by "A".
  5. The numbers of neutrons is equal to or greater than the number of protons in a nucleus
  6. Atomic mass number is alwasy greater than the atomic number of an element

NATURAL RADIOACTIVITY
Radioactivity is such a process in which the elements with the charge number(atomic number)greater than 82 naturally keep on radiating.

Radioactive Element

Element which have charge number greater than 82 are unstable and they emit radiations continuously. Such types pf elements are called radioactive elements.

Characteristics
  • The atom of radioactive elements change into atoms of the other elements due to emission of radiations.
  • Radioactivity is a spontaneous process and contineous for a long time.
  • The process of radioactivity is irreeversible.

Radioactivity was discovered by Henry Becqueral in 1986. He found that an ore containing Uranium emits an invisible radiation that penetrates through a black paper wrapping a photographich plate and affects the plate. In order to test his conclusion ;he performed many experiments.
Bacqueral took a closed box into which no light could enter and placed in it the uranium salt and photographic plates near to each other and also seprated by Aluminium sheets. In both the cases he obtained the same results. This shows that uranium salt emits strong radiation and they are not affected by the absence of presence of the sunlight.

Artificial Radioactive Elemenets
Using modern techniques, the elements whih are much lighter than the natural radioactive elements are made radioactive. Such elements are called artificial rdiactive elements.
Thus we include that all the radioactive from the radioactive material are not alike these are of 3 types , namely Alpha, Beta and Gamma radiations.


(α)Alpha Particles
The radiations that bend towards the negative plate of magnetic field and are composed of positively charged particles called α particles.
Properties
  1. The speed of α ranges between 1.4x10 7 m/s and 1.7 x 10 7 m/s
  2. α-particles ionizes the gas through which they pass.
  3. α-particles affect the photographic plate.
  4. They produces fluorescence in zinc sulphide.
  5. At atmospheric pressure they travel small distance in air.
  6. α-rays are positively charged particles because they carry a charge twice that of proton
  7. The mass of α particle is four times of helim atom
  8. In fact α -particles are also called helium nuclei.
  9. Each α-particle carries a positive charge of +3.20 x 10-19 C
  10. In Strong electric or magnetic field they show the same deflections as positive carges does.

β(beta)-Particles
The radiations that bend towards the positive plate of magnetic field are composed of negative charged particles called β-particles.

Properties
  1. The speed of β-rays ranges from 1 to 99 % of speed of light.
  2. β-particles produces ionization in air but this is less than α-particles.
  3. β-particles also affect the photographic plate.
  4. They produces fluorescence in barrium platinocynide.
  5. They can pass through the thick layer of matter.
  6. β-particles are also affected by electric and magnetic fields
  7. β-particles are also called fast moving electrons.
  8. They arry negative charge.
  9. The mass of β-particles is equeal as that of electron
  10. They can cause scintillation in certain substances like anthracene.

Gamma Particles
Thse radiations that go straight without bending means that having no charges are called gama particles.

Properies
  1. They moves with the speed of light
  2. The ionization produced in a gas y them is very small as compared to alpha particles.
  3. Gamma rays affect the photographic plates but this effect is much more than Beta rays.
  4. Gamma rays produces fluorscence in barrium platinocynide.
  5. The penetrating power of gamma rays is much more than beta particles.
  6. Gamma rays are such electromagnetic waves which are emitted by the nucleus
  7. They are simillar to x rays but they have hort wavelength.
  8. They have diffraction and interference phenomenon.
  9. They are not affected by electric and magnetic field.
  10. They can cause scintillation in certain substance like sodium iodide and zinc sulphide ZnS

HALF LIFE
The time during which the number f atoms of an element are reduced to one half is known as half life of an element.

We know that radioactive elements continuously emit radiations due to which they changes into new elements.
  • If an α-particles is emitted by an element then.
  • If an β particle is emitted by an element
The atomic no of the newly produced element remains the same but its charge number increases by one unit.It is due to fact that protons and neutrons are present inside the necleus which continuously change into one another. When a neutron emits a β particles ,it changes into proton.So the charge of the new element is increased by one unit.

Parent and Daughter Element
During radiation emission reaction, the original element is called the parent element and newly formed element is called the daughter element.The number of breaking atoms is proportional to the no of atoms left in that element.this means that no of initially breaking atoms is large which decreases with time.

NUCLEAR FISSION REACTION
The breaking of nucleus into two parts wih the release of large amount of energy is called nuclear amount of energy is called nuclear fission reaction

Types of Nuclear Fission Reactions
There are two types of reactions
1.Controlled Fission Reaction
2. UnControlled Fission Reaction

Controlled Fission Reaction
A system in which the fission reaction is controlled is called a controoled fission reaction.
If the fission reaction is controlled then the desired amount of energy can be produced in a useful manner.In the nuclear reactor. Boron or Cadmium rods absords the sur neutrons and thus nuclear fission reaction can be controlled.

UnControlled Fission Reaction
In the chain reaction as the fission reaction builds up the liberat energy goes on increasing. Th fission reaction thus become uncontrollable and hence whole of the matter explodes which resluts in great destruction. Such a reaction is used in atomic bomb.

NUCLEAR FUSSION REACTION

AProcess in which the light nuclei diffuse to form a heavier nucleus is called fusion reaction

During the fusion reaction mass is converted in to energy, which is subsequently released mainly as heat and other forms of energy. Th energy output of such fusion process is even larger than that released during nuclear fission reaction.

Difficult to produce Fussion reaction.
It is very difficlut to produce a fussion reaction because when nuclei are brought near each other for fusion , work has to against the elctrostatix force, which requires amount of energy or heat.

Source of solar energy
Scientist considered that the energy commimg from the sun and the stars is due to fussion nucleons.For producing alpha particles hydrogen has to be converted into helium.

Hydrogen Bomb
is an example of fussion reaction.For fussion reaction the required temprature is achieved by exploding an atomic bomb.


uDIFFERENCE BETWEEN FISSION AND FUSSION REACTIONS

FISSION REACTION
  1. In this process heavy nucleus splits up into light nuclei.
  2. Energy is needed to start fission reaction.
  3. In fission reaction unit mass produces small energy than fusion reaction
  4. Fission reaction is controllable

FUSSION REACTION
  1. In this process light nuclei fuse togatherto produce nucleus.
  2. A very high temprature is needed to start fission reaction.
  3. In fussion reaction unit mass produces largeenergy than fision reaction
  4. Fussion reaction is uncontrollable

Continue
Kindly correct me if sime error is done.
__________________
Always do what you are afraid to do
Saqib Riaz(TIPO KHAN)
Reply With Quote
The Following 2 Users Say Thank You to Saqib Riaz For This Useful Post:
Gulrukh (Sunday, September 26, 2010), taim231 (Wednesday, November 10, 2010)
  #4  
Old Sunday, January 17, 2010
Saqib Riaz's Avatar
Senior Member
 
Join Date: Apr 2009
Location: Rawalpindi
Posts: 723
Thanks: 440
Thanked 934 Times in 470 Posts
Saqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really nice
Default

Quote:
Originally Posted by saima muzaffar View Post
Really good try,,, kindly make such effort for computer nd solar system. Thank you
Thank you Saima.Inshallah i will try to post the topics which you asked for....
__________________
Always do what you are afraid to do
Saqib Riaz(TIPO KHAN)
Reply With Quote
The Following User Says Thank You to Saqib Riaz For This Useful Post:
Gold Engr (Saturday, September 25, 2010)
  #5  
Old Monday, January 18, 2010
rishzzz's Avatar
PMS - S&GAD
Qualifier: Awarded to those Members who cleared css written examination - Issue reason: Css 2010 - Roll no 5865PMS / PCS Award: Serving PMS / PCS (BS 17) officers are eligible only. - Issue reason: 2011 - Merit No. 43
 
Join Date: Jun 2009
Location: Invisible
Posts: 799
Thanks: 442
Thanked 712 Times in 438 Posts
rishzzz is just really nicerishzzz is just really nicerishzzz is just really nicerishzzz is just really nicerishzzz is just really nice
Default

@saqib riaz

i really liked the way u posted material.....as it ismore comprehensible for me to learn through these bullets than mere peragraphs and articulative writings....
Urposts are appreciable....

please post some stuff in this format regarding HUMAN BODY, PRODUCTS OF SCIENCE and Universe as well.....i wud b grateful to u n liable to pay gratitudes.....

Regards
__________________
“The greatest discovery of all time is that a person can change his future by merely changing his attitude.”
Reply With Quote
  #6  
Old Monday, January 18, 2010
Saqib Riaz's Avatar
Senior Member
 
Join Date: Apr 2009
Location: Rawalpindi
Posts: 723
Thanks: 440
Thanked 934 Times in 470 Posts
Saqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really nice
Default Coordination

Nervous Coordination
Is brought aboutthrough various elements of the nervous system which are:
  • Receptors
  • Sensory Neurons
  • CNS---Central Neurons System(Brain and Spinal Cord), made of associative neurons(intr neurons)
  • Motor Neurons(nerves)
  • Effector organs

The stimuli are recieved by the receptors which convey the messages to the CNS through sensory neurons or nerves.CNS consolidates the information of stimuli, comprehends it and formulates the type of response to be produced. The message of type of response are passed via motor meurons or nerves to the particular effectors which produce specific response.
Quote:
Nervous coordination is usually involved in producing rapid and short lived responses.
COMPONENTS OF NERVOUS SYSTEM

1.Neurons(nerve cells)
The structural and functional unit of the nervous system in all animal including human is neurons.This is highly specialized cell which contins the typical orgenells found in most eukaryotic cell.This is cell highly adapted for communication because of its wire like projection, the dendrites which are often further branchedand carry impulses towards the central cell cell body.The cell body is thicker region of neurons containing the nucleus and most of sytoplasm. The axon is the projection, generally very long that carries impulses away from the cell body. Usually neurons has a single axon. Fatty substance covering the axon is myellin along with the short regions of exposed axons are called nodes of Ranvier.Many axons and dendrites combines to form a single nerve.

TYPES
  • Sensory Neurons:They carry nerve impulsion (messages) from receptors to central nervous system.
  • Motor Neurons:They carry nerves impulsion (orders) from central nervous system to effectors.
  • Assocaited Neurons:They form central nercous system and are responsible for analyzing the message and issuing orders.


2.BRAIN
The brain is encased in a bony shell and a further protected by three membranes or meninges.The inner part of these covers the brain and richely supplied with blood vessels. It brings Oxygen and nutritions to underlying brain and protects it. The cerebrospinal fluid(CSF) lies between the inner and middle layers which provides cushioning and ions to the brain and spinal cord. The outer most layer is tough and fibrous and provide mechanical support.

The vertebrate brain is divided into three basic region
a)The Hindbrain
b)The Midbrain
c)The forebrain

a)The Hindbrain
The Hindbrain is chiefly concerned with involuntary, mechanical process. It consists of three primary structures.
  1. The Medulla Oblangta: which lies on the top of the spinal cord and contains many of the centres that controls onvoluntary process like breathing,blood pressure and heart beat.All communication betweeb brain and spinal cord pass through the medulla.
  2. The Pons: that is present on the top of the medulla oblangta and contains the longitudinal bundles of mylinated fibers running between brain and spinal cord and cenrols balance and muscles coordination
  3. The Cerebellum: lies behind the medulla and controls balance and muscle coordination

b.The midbrain
The mid brain lies between the hindbrain and forebrain and connects the two.It processes the visual and auditory information from eyes and ears before sending them to forebrain.


c.The Forebrain
The forebrain is most advance in human. Its lower most part which lies above the midbrain is called Hypothalamus.
  • Hypothalamus:
    which controls, heart rate, blood pressure, body temprature,hunger, thirst,sex and anger in addition to its harmonial role.
  • Thalamus:provides connection between many parts of brain and between sry system and cerebrum. It may also controls moods and feelings. Sleep may be influenced ny thalamus centre along with the midbrain and hindbrain.It concerned to keep the body alert.

    The Cerebrum i the top mosst part of forebrain. It is divided into two hemishpere, comrising 1.5 billions nerve cells. Each hemisphere is divided into four major lobes.
    1. At the back are occipital lobes which recieves and analyze visual indormation.
    2. At the lower sides of the brain are temporal lobe which are primarly concerned with hearing.
    3. At the front of brain are the frontal lobes which regulates fine motor control including movement involoved in speech.

Spinal Cord

The spinal cord extends from the foramen magnum at the base of the skull to the level of the first lumbar vertebra. The cord is continuous with the medulla oblongata at the foramen magnum. Like the brain, the spinal cord is surrounded by bone, meninges, and cerebrospinal fluid.

The spinal cord is divided into 31 segments with each segment giving rise to a pair of spinal nerves. At the distal end of the cord, many spinal nerves extend beyond the conus medullaris to form a collection that resembles a horse's tail. This is the cauda equina. In cross section, the spinal cord appears oval in shape.

The spinal cord has two main functions:
  • Serving as a conduction pathway for impulses going to and from the brain. Sensory impulses travel to the brain on ascending tracts in the cord. Motor impulses travel on descending tracts.
  • Serving as a reflex center. The reflex arc is the functional unit of the nervous system. Reflexes are responses to stimuli that do not require conscious thought and consequently, they occur more quickly than reactions that require thought processes. For example, with the withdrawal reflex, the reflex action withdraws the affected part before you are aware of the pain. Many reflexes are mediated in the spinal cord without going to the higher brain centers.

The Peripheral Nervous System
The peripheral nervous system consists of the nerves that branch out from the brain and spinal cord. These nerves form the communication network between the CNS and the body parts. The peripheral nervous system is further subdivided into the somatic nervous system and the autonomic nervous system. The somatic nervous system consists of nerves that go to the skin and muscles and is involved in conscious activities. The autonomic nervous system consists of nerves that connect the CNS to the visceral organs such as the heart, stomach, and intestines. It mediates unconscious activities.


A nerve contains bundles of nerve fibers, either axons or dendrites, surrounded by connective tissue. Sensory nerves contain only afferent fibers, long dendrites of sensory neurons. Motor nerves have only efferent fibers, long axons of motor neurons. Mixed nerves contain both types of fibers.

A connective tissue sheath called the epineurium surrounds each nerve. Each bundle of nerve fibers is called a fasciculus and is surrounded by a layer of connective tissue called the perineurium. Within the fasciculus, each individual nerve fiber, with its myelin and neurilemma, is surrounded by connective tissue called the endoneurium. A nerve may also have blood vessels enclosed in its connective tissue wrappings.
  • Cranial Nerves:Twelve pairs of cranial nerves emerge from the inferior surface of the brain. All of these nerves, except the vagus nerve, pass through foramina of the skull to innervate structures in the head, neck, and facial region.
  • Spinal Nerves:Thirty-one pairs of spinal nerves emerge laterally from the spinal cord. Each pair of nerves corresponds to a segment of the cord and they are named accordingly. This means there are 8 cervical nerves, 12 thoracic nerves, 5 lumbar nerves, 5 sacral nerves, and 1 coccygeal nerve.
  • Autonomic Nervous System:The autonomic nervous system is a visceral efferent system, which means it sends motor impulses to the visceral organs. It functions automatically and continuously, without conscious effort, to innervate smooth muscle, cardiac muscle, and glands. It is concerned with heart rate, breathing rate, blood pressure, body temperature, and other visceral activities that work together to maintain homeostasis.

To be continued.......
__________________
Always do what you are afraid to do
Saqib Riaz(TIPO KHAN)
Reply With Quote
The Following 4 Users Say Thank You to Saqib Riaz For This Useful Post:
ASP imran khan (Monday, August 16, 2010), Eager (Sunday, September 26, 2010), Gold Engr (Saturday, September 25, 2010), rose_pak (Saturday, July 03, 2010)
  #7  
Old Saturday, September 25, 2010
Saqib Riaz's Avatar
Senior Member
 
Join Date: Apr 2009
Location: Rawalpindi
Posts: 723
Thanks: 440
Thanked 934 Times in 470 Posts
Saqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really niceSaqib Riaz is just really nice
Default BioDiversity

Classification of Living Organisms.
  • Thousand of Different kinds of organis,s exists on the Earth.Some organisms distinctly different from one another and share only a few common characteristics, other resembles more with each other and show only a few differences while some are even identical.
  • Classification is the arrangement of organisms into groups and sub-groups.
  • About 2 millions species of animals and 0.5 millions species of plants have been discovered so far.
  • According to 'Darwin's Theory of Common Descent'. the organisms having common ancestry in the near past would resemble one another very closely, while other those having more distant common ancestory would show more interrelationships.
  • Organisms resembling one another more are placed in the same group while other showing more differences are put in the different groups. This type of grouping is called 'evolutionary taxonomy'


BASIS AND AIMS OF CLASSIFICATION

Classification is based on such features or characters that are simmilar in one kind of organism and different in different kid of organism. The character which can be used in classification include external morphlogy, internal morphology ( anatomy), physiology, cell structure especially the number of chromosomes and chemical composition and embryology.
  • Occurrence o some common characters in different organism indicate their common ancestral origin. This similarity because of common ancestral origin is called Homology.e.g arm of monkey, flipper of a whale and wing of bat show homology. Aparently they do not look alike but their basic internal structure is almost similar. Such organs which have same basic internal structure and embronic development are called homologous organs
  • Fruits of all plants whether sweet or sour , small and dry, or large or fleshy are homologous structure because they all develop from ovary of flower and have common origin.
  • On the other hand , wings of and insect and bird despite performing the same function are not homologous because their origin is different. Such organs that are similar in function but different in basic structure are called analogous organs.

Aims and Objective
1. Determine similarities and differences between different organisms.
2. Arrange organism according to similarities and differences.
3. Identify the organisms on the basis of their structure and other prominent features and study them systematically and logically
4. Find out inter-relationship of organism.

Units of Classification
  • Species----Basic Unit---A group of organism that can bred with one another in the nature and produce fertile offspring.All member of species have same number of chromosomes in their cells and character in common.
  • Different but closely related species are grouped togather into a large category known as genus(plural genera).
  • The closely related genera are grouped into a still higher category known as family.
  • The families are grouped into an order.
  • Orders are put together into a class
  • Closely related classes are grouped into phylum (plural Phyla) which are also called divisions among plants, fungi, and algea.
  • The phyla or division are in turn grouped into Kingdom

KINGDOMS OF LIVING ORGANISMS

1. Two Kingdom System
  • Oldest Classification system.
  • Living organism are placed into just two kingdoms. Plants and Animal
  • Presence of cell wall and ability to make their own food were considered the most important characteristics of plants.
  • Lack of cell wall and inability to make food and characteristic mode of nutrition and ability to move from place to place are the most significant characteristics of animals.

1. FiveKingdom System[*]Margulis and Schwartz (1982) has proposed five kingdom classification.[*]This system claims to solved the difficulties faced in the two kingdom classification system. [*]According to this system all organism are classified into five kingdoms which are:
  • Kingdom-Monera (Prokaryotes)
  • Kingdom-Protista
  • Kingdom-Plantae
  • Kingdom-Fungi:
  • Kingdom-Animalia

    1.Kingdom-Monera (Prokaryotes)
    • The kingdom Monera includes all microorganisms with prokaryotic cells.
    • Prokaryotic cells lacking nuclear membrane, plastids, mitochondria and advanced (9 + 2 strands) flagella.
    • They are solitary, unicellular or colonial. Predominant mode of nutrition is absorption but some groups are photosynthetic or chemosynthetic.
    • Reproduction is primarily asexual by fission and budding,etc

    2.Kingdom-Protista
  • The Protista (also called Protoctista) are generally single-celled eukaryotes (cells with membrane bound nuclei) such as Euglena and Amoeba.
  • Nutrition by photosynthesis, absorption, ingestion and combination of these
  • Reproduction is asexual and sexual type. Motility by flagella or by other means or nonmotile.

3.Kingdom-Plantae[*]The members of this kingdom are mostly multicellular autotrophs, with cellulose wall and frequently vacuolated, eukaryotic cells.[*]Chloroplasts present; principal nutritive mode is photosynthetic but some absorptive.[*]Primarily nonmotile, living anchored to a substrate. Structural differentiation; reproduction primarily sexual, e.g., Rhodophyta, Phaeophyta, Chlorophyta, Bryophyta, Tracheophyta (Pteridophytes, Gymnosperms and Angiosperms).[/LIST]

4.Kingdom-Fungi[*]he fungi include multicellular heterotrophs, such as mushrooms and molds as well as unicellular yeasts with eukaryotic nuclei dispersed in a walled and often septate mycelium[*]Fungi decompose other biological materials, develop from spores, lack plastids, photosynthetic pigments and flagella. Nutrition absorptive; chitin in cell wall. Somatic tissue differentiation absent or limited.[*] Reproductive tissue differentiation and life-cycle elaboration masked in higher forms[*]Primarily nonmotile (but protoplasmic streaming in mycelium), living embedded in a medium of food supply. Reproduction asexual and sexual both types. No embryo is formed.[/LIST]
5.Kingdom-Animallia[*]The members of this kingdom are multicellular heterotrophs with wall-less eukaryotic cells, lacking plastids and photosynthetic pigments.[*]exhibit movements and develop from embryos[*] Nutrition primarily by ingestion with digestion within an internal cavity but some- forms are absorptive.[*]Sensory neuromotory system[*]Reproduction predominantly sexual[*]They include sponges, coelentrates, insects, birds, mammals,etc.[/LIST]
__________________
Always do what you are afraid to do
Saqib Riaz(TIPO KHAN)
Reply With Quote
The Following 2 Users Say Thank You to Saqib Riaz For This Useful Post:
Gulrukh (Sunday, September 26, 2010), Habib orakzai (Saturday, October 02, 2010)
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Very Important : How to Prepare Study Notes Shaa-Baaz Tips and Experience Sharing 2 Wednesday, March 06, 2013 12:12 AM
How to make effective notes? Omer Frequently Asked Questions 3 Tuesday, July 28, 2009 06:44 PM
Effective Study Skills Sureshlasi Tips and Experience Sharing 1 Friday, November 16, 2007 08:28 AM
Regarding Notes Anonymous84 Tips and Experience Sharing 1 Wednesday, August 15, 2007 06:56 PM


CSS Forum on Facebook Follow CSS Forum on Twitter

Disclaimer: This is not the official website of Federal Public Service Commission Pakistan. This is a non-commercial website helping individuals who intend to join civil service of Pakistan. The material on this website is provided for informational purposes only. We do not claim that the site is an exhaustive compilation of information about Civil Service of Pakistan neither represent or endorse the accuracy or reliability of any information, content contained on, or linked, downloaded or accessed from any page of this website. These materials are intended, but not promised or guaranteed to be current, complete or up to date. However, honest efforts have been made to provide comprehensive information for the benefit of users. The documents and material displayed or mentioned on this site are not official copies. Please contact FPSC for updated rules and regulations governing CSS examination.

Sponsors: ArgusVision   vBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.