1969-02-06 — Page 23

育教僑華·頁三第張六第 日十二月二十年申戊磨 WAH KIU YAT PO

報日僑罩

四期星日六月二年九六九一屦公年八十五國民中

(接第六張第二頁)

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Egge

larva

•Imgo

Culex

Eggs are stuck A siphon with together in

It stands with.

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上文中學會考試題預習

生物科 (十四)

·廖百

small raft floating on

the surface.

of water

Aedes

Solitary e2AST floating

separately on

the surface

spiracles on the eighth abdominal segment. Tha body makes an angle of 45° to the surface of water when breathing. Some as iri Culex.

with body

parallel to

surface.

Game as Culex..

all legs in

[C

1969

文中學會考試題預習

contact with

surface and

現代數學科

BIOLOGY (14)

Answer to the exercise of last week:

Ans

(a) Describe, giving fully Labelled diagrams.

life-history of a Named mosquito. (b) Make a comparison of the Culex, Aeaes, and Anopheles mosquitoes under the headings of (i) ezz (11) Jarya and (iii) imago.

(a) The life-history of Culex mosquito is described

as the follows

Lgg stage: The eggs are sparsonspeo ana are laid in masses of 200-300 floating on the surface of stagnant water.

Larval stage: The larva soon emerges, consisting of a head, thorax and a nine segmented abdomen. It grows through four ecdyses, its aquatic habit necessitates frequent visits to the surface for respiratory purposes. It attaches itself beneath the surface film with spiracles of the eighth abdominal segment. projecting for the intake of air. The spiracies are situated at the end of a tube, the siphon.

When the larva is moving through the water, the

spiracles are closed.

The head of the larva bears a pair or eyes, a pair of short antennas and two mandibles. There are also two small mouth-brushes. By tim movement of the mouth-brushes, small organisma and other food matters are drewn into the mouth.

Pupal staga: After a few weeks, the lärve is about half an inch long and changes into the pupa. The pupa consists of an enlarged head and thorax together with slender abdomen. The whole body of the pupa still hangs beneath the surface of the water by means of a pair of respiratory trumpets. In the head and the thoracic parts, developing eyes, wings, legs and antennae of the future adult can be found. At the end of the abdomen is a pair of tail plates which act as a tail-fin for swiming.

After a few days time the pupse skin splits and the imgo emerges. Adult stage: Fihe newly formed adult which remains for a while on the pupa sıçın above the surface of the water, where the wings soon dry and the cuticle hardens, after which the insect forsakes the water for its life on land.

proboscis

Compound

-Eve

1. Eggs

Antenna

Ley

Wing,

Thorax Compound

Eye

Respiratory trumpet"

Antenna

Lag

Tail-plates

3. Ариран

Eye

Antenna Mouth brush

· An Adult (Female)·

Thorax

Respiratory Siphon

Anal

8th abdominal jills Segment.

2. A Larva

The Life-History of A Culex Mosquito.

(b) The table below is a comparison of Qulex,

ades and Anopheles:-

of water

Solitary eggs

The siphon

It stands with

is absent. But

with air

shopn- chambers flat-it possesses a

elea

ing separately pair of

on the surface of water,

spiracles on the eighth abdomina 1

segment. The body lies parallel to the water surface when | breathing!

body at 45° to the surface

and often with last pair of legs raised.

2. lake a fully labelled drawing to show the

external features of a typical bony fish. How is the fish adapted to its mede of life in respect of (a) locomotion and (b) respiration?/

Ans

The diagram below 25 a drawing of a typical bony fish:

Lateral line

Dorsal fin

Nostril

Scales

caudal

Mouth

pectoral fin

Operculum

•Anal fin

Anus Pelvic fin

A Diagram Shows The External Features Of A Typical Bony Fish.

(a) The characteristic features and structure.

in a bony fish are adapted to its locomotion habit:-

(i) Its body is stream-lined in shape to

minimize the friction, which caused by the water when the fish is in swimming. (ii) It is clothed in scales which assist the

Interml skeleton in maintaining the shape of the body and protecting itself from injury.

A lateral line contains minute sensory organs that enable the fish to detect low frequency vibrations, movements, and perhaps pressure changes in the water, (iv) The lens of the eyelid less eye is

spherical, and it focuses by moving backwards and forwards.

(v) The puoils of the eyes are large to permit more light entering its eyes. This enables the fish to see in darkness and to find the movement of objects farther away. (vi) The ears have no external flaps, and are

concerned with almost exclusive

rapher fan with sound when

(vii) A swim bladder lying in the dorsal portion of the coelon, which is filled with gases. It functions to adjust the specific. gravity of the body so that the fish can stay at various depths with a minimum of affort.

(viii) it possesses fins and a powerful tail..

These organs enable it to swim rapidly and to escape from its enemies,.

(b) For respiring in water, host fish have no true lungs and can only breathe dissolved oxygen in water

a

The characteristic respiratory organs of fish are its gills which located in the gill slits and attached to the visceral arches. The gills are fleshy outgrowths on the walls of the pharynx, and are richly supplied with blood-capillaries. Water enters the mouth continually, flowing over the gills and out. through the gill-slits which are covered by the gill-cover (operculum). As the blood in the gills is so near the flowing water, gas88- exchange takes place, during which carbon dioxide diffuses from blood to water and oxygen diffuses from water to the blood.

Questions Tor this week?

(a) Give a labelled diagram or a bird, showing its

chief external features, dy what ways 18 a bird specially adapted for flight?

(b) With the help of diagrams, describe briefly,

the structures of a wing feather of the bird:

wescribe the structures of a bird's egg and give the function performed by each part that you mention.

(b) write a short account or the life-history of)

a Named bird

x: also draw.

(3) Draw of graph the graph

The last two graphs above illustrate that the graph of a relation and the graph of its inverse is symmetrical with respect to the line defized by y = x.

7. Functions defined

Function is a special kind of relation. Functions are those relations such that no tw ordered pairs have the same first component Examples:

(1) R; = {(1,2), (2,3), (-1,0), (4,5){

is a function,

(2) R2 = {(2,a), (3,b), (2,c), (4,0)) is not a

function, for (2,a) and (2,c) are having the same first component.

In other words, if function f ie from A into B it means that to each element in ▲ there is assigned by some rule a unique element in B. The function from A into B is designated by r: A→B read "r is a function of å into B." A is called the domain of the function while B or a subset of B is the range of the function. If a & A end b is ap element in B corresponding to it, then b is called the image of a, denoted by f(a), f(a) is read "for a."

Examples:

(1) Let A = {0,1,2,3] and B = {1,2,3,4). If a

function of A into B is defined by the rule f(x) = x + 1, then f(0) = 0 1 or 1, f(1)

• 1 + 1 or 2, f(3) = 3 + 1 or 4 and so on.

of 1 is 2 and so on 10:30 5, of 1 Thus the image of 0 is

(2) Let I be a function from D into D and be

defined by f(x)=. Then the image of -2 is -8. of 3 is 27 and so on.

Functims, mappings, and transformations

The Lerme function, mapping, and transformation mean the same basically, When the set A and the ser Bare sets in general, but not sets of numbers, the fumtion f of A into B is commonly called a mapping or a into B. A mapping may be designated by a diagra

xamples:

00

(1) The first example in the last section 19 also

mapping which can be shown as below,

(2) If 4 fa,b,c,d), and 8

f(a) • o, f(b)

*

mapping of A into B is shown as

B

3) If - la,b,c,d,e ) and B = {1,2,3,4 and

f(a) - 1, ((b) - 3, f(c) = 4, fld) * 2, fle) - 4, then the mapping of A cato Bis

shown as

#2

Transformation is another name for function. We shall consider it under the topic of geometrio transformations latter.