1967-12-28 — Page 10

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日七廿月一十年未丁證設,

WAH KIU YAT PO

13英文中學會考試題預習專欄

佳物科

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徐錫褸 R

Biology: (9:

Answers to axer -18es for last weekt

·) Make a list or tight named multicellular

:organisms: (plants and animals) that you have

found in any one named habitat (or in a balanced aquarium) you have studied.

(b) Give a brief thustrated account of Jure. history and habits of one plant and one animal from

our list

The typical multicellular organdams in pond life are as follows i

1. hydra

2. Pond snails of various form

Fish i.e. eels

4. Frogs in various stages

5. Spirogyria.

6. Duckweeds

Water lilies

Canadian pond weeds.

Spirogyra! is a multicellular plant found along the sidee of fresh water ponds or slow-running streams..

1t8 life history can be classified into two types according to conditions..

The mature-apirogyra filament wound. increase in length by cell division and elong- ation in a longitudinal direction only, After The unclear division the plant cell by forming a crass wall divides into two young cells which develop its cylindrical-Bape structure. Then each young cell slowly grows in length to the normal size,

Vegetative ke Broduction - when condition is favourable parts of the mature plant body. become separated to give rise to now Individual without any advious change in the protoplasm. Then the filaments separate Into two shorter Lengths of the fliment. The reproductive method is termed fragmentation. Jexual reproduction

113 when aondition is unfavourable or

by chance the two mature spirogyr arrange searallel to each other ocours. The cells of the two Be would Iink together by Yormd

The contents of the “ink the chloroplasta dis

Filaments

pents

白

condition where it burst out of ita zygospore wall to form & new filament by onla division.

The life history and habitat of a multicellular animal (Frog) i

Habitati

Fron is found in fresh water ponde, lakes, olanted fields or ditches

Breeding season. It 18 around Maron or April; each year.

Its life history can be divided into the following stages

1. Mating In spring the mature male frogs ride e nick-a-back, fashion on the mature female, Egg laying 'After gating, the female frog. lay 1000-2000 eggs on the shallow pond bottumay Then the male frog: sheda apera: over them. Fertl] 1eation. When the fusion of a male. sperm and a Temale egg starts fertilization is said to take place.

Development - 19 the nrocess of changy during which the fertilized egg becomes a multicell

ular frog.

(11 Embryo - 10-12 days after fertilization thal

zygote develops and has tall, heed anc cement gland. The energy and raw materials

for 20

growth are supplied from ite yolk while oxygen for respiration diffuses from the: pond water through the egg membranes and surface of the embryo.

(11) Larva - 2-3 days after hatching, tadpole is

athens, mouth and external formed Tail lengthens,

ills start to functions by inhaling dissolved ozygen through external gilis The tadpole is fed by pondweeds.

2. weeds after hatching; the operculum or the tadpole begins to grow and internal gills emerged..

1 month after hatching, formation of hind limbs first appears and he tadpole inhales dissolved ozygen through internat gills. The animal 18: gradual changed to take in Carnivorous diet

2 months after hatching

lunga develop and

the animal pay frequent visits to surface the ponds,

3 months after hatching skin and young fro is for

•the animal:ca sta

complete absorption

the ther

leaves the water and ty

inhaling free Özygen from the at hrough skin and mucous membrane

mou

and lungs. The young frog feeds on worms anatle and flies.

13 30147 And describe.

KUNSTAFOBOZ

ontent of one.

chemical struc

of plants, and

are then dissolved. The da moved to the other ced rough the conjugation subs. Then

passing

chemica

to the

and

日八十月二十年七六九一股公年六十五國民囊中

育教信亊

the mountain rocks it is termed cedentary; if the deposited soil is accumulated in river beds,

glaciers or the sea it is termed sedimentary or alluvial. While chalk soils and coral cande consist almost wholly of the fossil remains ori marine organisms with calcareous shells.

Soil consists of a mixture of sand and clay particles, humus, witer, air, dissolved mineral Balta and bacteria. Generally the major parts of Boll materials are insoluble.

If the doll particles are generally BIOBAJ, and colloids are formed, the soil fa a clay.

If the soil particles are relatively large; the soil is sandy.

Clay soils hold water and have little air in then, while sandy soils are free-draining and well-serated. Capillarity is high in claysoil,

The Inauffiedenay: of water causes a sand a low #pecific heat, so that it responds rapidly to changes in atmospherio temperature. The opposite is true of clays

The numua 35 composed of rotten. or decayao organte material. It makes the soil brown in color to a large extent. It is most fertile and supplies planta with minerals which were part of the. organism from which the humis was derived. It is of great value in soil in that it holds water in quick- drying sands, and loosens the texture of heavy soile by its fibrous constituents.

The soil water is of diluta 6a1 Dustic, ac10 eolution, containing dissolved minerals. Under normal conditi

the water molecules are held

arbund sech article by capillary attraction.

Only the espillary water is available to plants.

The adc; contained in the spaces: bitween the soil particles, is for respiration of soil organisms and plant roots. The nitrogen in the air is utilized by nitrogen fixing bacteria.

The nérale salts, such as calcium and hosphorus, are extracted the soil by plants, which may later be eaten by animals. The salts are deposited and formed the bony tissue which in return will form local concentrations of calcium and phosphorus in the soil when the animals die,

By the help of bacteria and fungi in the gulL the formation of altrates (essent lab compound of a, fertilizer) from ammonia in the nitrogen cycla makes possible.

The animals such as earthworms and insect larval burrow in the soil, improving the drainage. And ow the air to penetrite. Large herbivorous Animals living on the surface of the soil can

dus atructure by denuding it of vegetation, affect and consequently causing ecil erosion. Dead plant. rpets Cecaying in the soll leave humus filled charmels, which aid aeration.

Oxercise for this weekte

iftarances hatween a bony fish and

ly the variou

elation

zu ronmarit”

in the tre

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中文列爲官方語文

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一致同意,百分之九十九點二五同系均 新亞學生訪問調查結果,廿六位師長

奋月

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尤及新界各中小

第四屆學校舞蹈節

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報名,元月三日及四日,每日上午九時三十分盆十二時,中

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“正月份新班牙自

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AND GRETEL

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GROUP CERTIFICATE COURSIS)

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