3日僑華
118 life history can be described as the
following stages
育教価華頁一第張六第日二廿月三名獎西服夏 WAH KIU YAT PO
育教
僑華
1969
E
直預習
生物科
(廿七)
百琴
BIOLOGY (27)
Answer to the questions of last week
1. Write on the line at the right of eaon statement
Ana
or queation the number preceding the word or. expression that best completes the statement wa answers the question.
11.
7.
12.
(5)
3.
8. (1
13.
14. 15. (2)
11. (a) Make a list of Eight named multicellular
organisms (plants and animals) that you have. found in any one named habit (or in a balanceo aquarium) you have studied.
Ans
(b) diva a brief illustrated account of the lite
history and habits of ONE plant and ONE animal from your list.
(a) Eight multicellular organisms found in a frest
water pond arei
(i) Hydra
(ii). Pond shails of various forma
(iii) Fish Leg. eels)
(iv) Frogs in various stares
(v) spirogyra
(vi) Duckweede
(vii) Water lilies
(viii) canadian pond weeds
(b) Spriogyra
It is a multicellular plant found in the fresh water ponds, ditches and slow-runnine streams.
Its Jure history can be classified into two types according to conditions of the environment.
(1) Asexual reproduction
-
when conditions
are favourable, parts of the mature plant body become separated to give rise to new individuals without any obvious change in the protoplasm. The filaments separate into two shorter lengths of young filaments. This reproductive method is known AB
fragmentation.
tiil Sexual reproduction - The reproduction
occurs when conditions are unfavourable or by chance the two mature spirogyra filaments arrange themselves parallel to. each other. The cells of the two separated filaments link together by forming a conjugation canal. The contents of the two linked cells shrink, the chloroplasts disappear, the cross walls are, then dissolved. The content of one cell is moved to the other cell by passing through the conjugation canal. Then the two nuclei fuse together. Fertilization is said to have taken place. As a result of fertilization a zygospore is formed. The zygos pore continues to develop as it is set free by decaying the old cell walle në the filament. It is able to resist unfavourable conditions untal it bursts o of its outer wall to form a new filament again by cell division. This type of reproduction in spirogyra is termed conjugation.
Short projection
Conjugation
Tube
-
(Mating stage In spring the adult MALO
frog mounts on the back of a mature female. frog, and is carried about by the female for a few days in water. (ii) Fertilization of egge and development or
fertilized eggs After mating, the female frog lays 1000 to 2000 eggs on the shallow pond bottom. Then the male sheds sperne over them. When the fusion of a sperm and egg starte, fertilization is said to take place. After that the fertilized egg forme an embryo by cell division.
Embryonic stage About 10 to 12 days arter fertilization a young embryo formed has a tail, a head and cement gland. The energy and raw materials for growth are supplied from the yolk of egg. While the oxygen for respiration diffuses from pond water. through the egg membranes and the surlace of the embryo.
aays arter hatoning, the tadpole is formed. The tail lengthene. The mouth and external gills start to function by inhaling dissolved oxygen through the external gills. The tadpole feeds on pondweeds,
(sv) Larval stage
2 weeks after hagring, ne oparculum, of the tadpole grows out and internal gilla emerge.
One ai ves nátoning, une formation of bind limbs first appears and the tadpole inhales dissolved oxygen through the internal gills. The animal gradually changes to a carnivorous diet
Two months after hatching, lungs develop and the animal visits to the surface of the pond frequently,
Three months after hatching, the animal casts ite skin and the young frus is formed when the tail is completely absorbed.
v) Adult stage
The young log now Leaves the water and tries to live on land by inhaling free oxygen from the atmospheric air through its body akin and mucous membrane of the mouth and lungs. The young frog finally feeds on worms, anails and flies. It attains sexual maturity in the third year.
-Jelly Coat
•Animal pole
•Vegetative pole
@
(1) New Laid Egg
Fye
四期星日八月五年九六九一公年八十五國民辈中
b
獲公司獎學金 工的子弟。
QUERS. YES BRUCEROZKIEHS-T► WRABZONRY SYBUGI
附質爲枰縠士與做(右)及國述》。
h Single Cell from The Filament of Spirogyra
Mycelium
Spo- rangium
·A young Embryo
(11) Ready to Hatch (10 days).
Anus (iv) Internal Gills Stage (3-5 weeks)
Columella
Spores
怡和員工子弟
CH-EIXERY=19 *** (HE)CERCHEVY LOCAT
sporangiophore
stolon
Rhizoid
A Mycelium of Mucor
Spores Columella
・A Mature Sporangium
Mucor
(b) The table below is a comparison of feeding
and reproduction of ducor and Spirogyra.
Feeds on the moist organic matters such as butter, chesse, leather, bread and pericarp of orange.
Spirogyra
Makes food by the process of photosynthesis so that PAM meteriale such aa water, light, chlorophyll and carbon dioxide are essential.
Muscle of
tail
Mouth
External gills
Anus
Feeding
(ii) External Gills stage
(2-3 weeks)
Spiracle.
Hind limb
Sony jaws
Reproduction
(V) Hind Limb Stage.
Fore limb
∙Bud of fore-limb
"(6-9 weeks)
Asexual mean
Yam
Asexual method
Having special. organ.
Simple splitting
aporangiophore
Hind limb
Sexual
mean
(Vi) Completion of Metamorphosis
the
Sexual method
Yea.
Conjugation of two side filaments takes place. Fusion of two motile
gametes of the
Bame sind
wappens and a
zygos pore 18 formed. in both.
Yea
Yes
Same as mucor
Two filaments lying
Side by Side
The formation of Conjugation tube
•New
(vii) A young Frog
The Development Of A Froz
III, (a) Maks large labelled drawings to show the structure of Mucor and Spirogyra.
(b) Show the similarities and differences between
Mucor and Scirogyra with reference to (i) feeding, (ii) reproduction.
Asexual encystment
Protection
of zygote
No
A tough round capsule called cyst.
Contents of
Sporangia
the zygote
No
A rectangular
resistant capsule called cyst.
Filaments
-Zygo-
filament
Ans.
(a)
The formation of the germination Zygospore
of Zygospare
Diagrams showing Conjugation in Speropyra
FIOS:
It is a multicellular animal found in fresh water ponds, lakes, ditches or planted
fieldg.
pyrenoid
Nucleus.
Cytoplasmic
Strand
-Мисала membrame -Cellulose wall -Cytoplasmic
membrum
•Spiral
chloroplast
·Vacuole
cytoplasm
Questions for this week:
1. (a) What do you understand by "transpiration"?
Distinguish between transpiration in flowering plants and perspiration in mammals. (b) What external factors determine the sale wi
(i) transpiration and (ii) perspiration?
2. (a) What are the main functions or tag „AAR EN BELLANKO que más
blood? By means of a labelled diagram, show the structure of a Named mammalian heart and indicate the course followed by the blood in the heart of this mammal.
b) State Five differences between arteries and
veins. What happana to the blood as it passe through the capillarias in lunga?
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