assignment

1. Zoology practical
Name : S
hivani S
ingh
Batch : A
Exam Roll No.: 21219BOT066
Class Roll No.: Z-O66
AIM :To distinguish between male and female Drasophilia , identify
their mutant types and study their life cycle.
REQUIREMENTS: Drasophilia , empty transparent jar , ripened fruit
, lid with perforations.
Average temperature throughout the experiment – 26 degrees
Celsius.

2. THEORY -
Drasophilia melanogaster, commonly known as fruit fly is one of
the most valuable in biological research, particularly in genetics
and developmental biology.
The reason of Drasophilia being most extensively used organism in
genetic experiments is as follows-
 It hasashort lifespan 10-12 daysand asimplereproductive cycle.
S
o, a large number of generations can be seen a short period of
time.
 Their body size ranges from 2-4 mm and hence, they can easily
be seen without microscope.
 A single matingproduces large number of offspring.
 They can easily be grown in asimple synthetic medium.
 Male and female fruit flies exhibit distinct sexual dimorphism.
 Presence of Polytene chromosome .
 They do not act as vector of any disease.

3. CLASSIFICATION-
PHYLUM :
Arthropoda
CLASS:Insecta
ORDER:Diptera
GENUS :Drasophilia
SPECIE :melanogaster

4. Set-up:
TW O SET-UPS W ERE PUT IN SEPARATE PLASTIC BOTTLES.
Date: 14/10/22 Time: 7:00 am
S
ET-UP1: Horlicks (drink powder)
S
ET-UP2: Ripe bananapieces.
 openingof the bottles was left uncovered.
 After await of 6-7 hours, 12 fruit flies were lured into S
ET-UP2.
 Very few flies entered S
ET-UP1.
 The bottles were then closed with the lid having minute holes to
prevent fliesfrom escapingand to maintain proper air supply in the
jar.
The trap was then allowed to rest and kept under observation

5.  After the observation of initial
reproductive stages of fly in the jar,
presence of both male and female flies in
the jar was confirmed.
Male and female were distinguished based
on sexual dimorphism.
 The tip of abdomen is rounded in males.
 The tip of abdomen is elongated
in females and females are generally larger.
Observation:–
Set-up 1:
Thesetup waskept at an optimal temperatureof 27 C temperature
and the experiment wascarried out with the standard procedure
but it wasobserved that after 6 daysno further growth happened
and all the flies were dead.

6. Problable reasons for the death of developmental stages-
The wings of the flies might have got stuck to the sticky
food(horlicks powder).
Set-up2:
20th
October : Eggs were observed.
22th October : White coloured worm like larvae seen(1st
instar ).
23rd
October: 2nd
instar larvae are seen. These are larger in
comparison to 1st
instar larvae. ( MoultingPeriod- 24 hrsapprox.).
24th
October : Larvae further grows into 3rd
instar stage. (Moulting
period – 24-25 hrs approx. )
26th
October: Yellowish white coloured immobile pupa
spotted.(Moultingperiod – 35 hours approx. )
28th
October : Pupamatured and turned orange-red in colour.
31st
October : Pupahatches into fully developed flies.

7. SET-UP 1:
Dead flies

8. SET-UP 2:
1: S
econd instar larva 2: Mature pupa 3: first instar
larva
1 1
2
3
4
4: Third instar larva

10. Discussion:
LIFE CYCLE-
 Wholelifecycleof thefruit fly took 11 daysto complete( from embryo
to adult).
 Life cycle consisted of 4 morphologically distinct stages-
a. Egg/ Embryo : Hatches in about 2 days to give rise to larvae.
b. Larva: White coloured worm like organism. Thisstage lastsfor about
3-4 days. S
ize of the larva increases as 1st
instar stage progresses to
develop into 3rd
instar stage.
c. P
upa : Pupa are initially yellowish – white in colour and progressively
becomes darker as it matures.
Adult : Feed , breed , lay eggs and continue the next generation
Thank you