The document discusses the aquatic adaptation of mammals. It acknowledges those who helped with the seminar topic. The contents include introduction, adaptation of aquatic mammals, modification and loss of original structures, development of new structures, types of aquatic mammals, and conclusion. It describes various anatomical modifications that aquatic mammals undergo, such as streamlined bodies, flippers, valvular nostrils, large lungs, blubber, and tail flukes to adapt to aquatic living.

1. AQUATIC ADAPTATION OF
MAMMAL

2. ACKNOWLEDGEMENT
We are very much pleased to submit our seminar
topic on AQUATIC ADAPTATION OF MAMMAL for
B.Sc. 3rd semester. We sincerely thanks to our
honorable principal Dr. Prasanna Kr. Dutta to give
us opportunity for preparing the seminar topic and
our Professors Dr.Gayatri Agni Bora(HOD) and
Dr.Bikramaditya Bakalial of Zoology department of
our college for guiding properly the same.
We are also thankful to our other respected
teachers of the department and our friends and
parents for supporting us and help to make the
seminar on the above topic.

3. CONTENT
 INTRODUCTION
 ADAPTATION OF AQUATIC
MAMMALS
 MODIFICATION OF ORIGINAL
STRUCTURE
 LOSS OF STRUCTURE
 DEVELOPMENT OF NEW
STRUCTURE
 TYPES OF AQUATIC MAMMALS
 CONCLUSION
 REFERENCE

4. INTRODUCTION

5. ADAPTATION OF AQUATIC
MAMMALS

6. MODIFICATION OF ORIGINAL
STRUCTURE-
 A. Body shape – The body shape of
aquatic mammal become stream lined
with elongated head and indistinct neck
and tapering posterior region.
 B. Body size and weight – Aquatic
mammals develop a layer body size
which help to reduce heat loss and due
to buoyancy increased weight does not
produce any problem.

7. MODIFICATION OF ORIGINAL
STRUCTURE-
 C.Origin of flipper-
Forelimbs are modified
into skin covered
unjointed flipper .
 D. Upper valvular nostrils
– The nose opening is
move to the dorsal side of
the head that help animal
to breath air without
exposing its body. Valve
support the nasal
opening.

8. MODIFICATION OF ORIGINAL
STRUCTURE-
 E. Mammary gland – In
lactation the mammary
duct dilates and acts as
storage of milk which is
pumped directly into
the mouth of the young.
 F. Oblique diaphragm –
It makes thoracic cavity
larger that provide
more space for lungs.

9. MODIFICATION OF ORIGINAL
STRUCTURE-
 G. Large lungs – It allow the
animal to stay for a longer
period of time under water.
 H.Endoskeleton–
Modification of skull bone,
cervical vertebrae ribs can
be seen bones are light,
spongy and fill with oil.
 I.Teeth– Various modification
of teeth in different orders
can be observed, mobility of
jaws reduced.

10. Loss of structure-
 D. Lacrimal gland
and all kind of skin
gland are absent.
 E. Skin is devoid of
muscle and nerve.
 F. Pelvis portion
become rudimentary.

11. Development of new
structure-
 E. Foam – Thy have foam like
substance made up of fat
mucus and gas in the middle
ear which improve their hearing
under water.
 F. Melon – It is a receptor
organ present in front of nostril
which detect pressure change
in water.
 G. Harderian gland – This
gland secrete a fatty substance
which protect the eye under
water.

12. Development of new
structure-
 C. Blubber – A thick
subcutaneous layer of fat
called blubber act as a
thermo regulator and
maintain internal body
temperature. During deep
diving it absorb hydrostatic
pressure.
 D. Baleen – In some whale
the upper jaw develop rows
of numerous triangular horny
plate called baleen, serve as
effective sieve to capture
plankton.

13. Development of new
structure-
 A. Tail fluke – Aquatic
mammal develop large,
lateral or horizontal
expansion of skin in their
tail these called tail fluke
which are not supported
by fin rays or bones.
 B. Dorsal fin – They
develop an adipose dorsal
fin which serve as rather
or keel during swimming.

14. Loss of structure-
 A. Hair form body
surface degenerates
making the skin smooth
and less resistance
while moving in water
 B. Pinnae are also
absent.
 C. Nictitating
membrane of eye
absent.

15. Types of aquatic mammals-
 A. Amphibious mammals –
These numerous live in
land but go to water for food
and shelter. So they show
partial adaptation. e.g,
Hippopotamus, walrus etc.
 B. Completely aquatic
mammals – These
mammals never come to
land and are perfectly at
home in water. e.g, Blue
whale,dolphin.

16. CONCLUSION-