1.
Animal Diversity: Vertebrates
by
Maryam Riasat
BIRDS

2.
Birds

3.
Birds
 Birds includes pigeons, owls and flamingos
 Birds are bipedal and clawed vertebrates
 Body is covered by feathers
 Birds body is divisible into head, neck, trunk
and tail
 Small head is placed on a fairly long movable
neck
• A beak with no teeth
• Have sharp eyesight
• A lightweight but strong skeleton
• Production of hard-shelled eggs
• Forelimbs are modified into wings
• Hind limbs are strong and are useful to walk
• High metabolism
• A four chambered heart
• They have well developed flight muscles

4.
Respiration
 The birds respiratory system is
different from that of other
vertebrates
 They have relatively small lungs
plus nine air sacs that play an
important role in respiration
 The air sacs permit a
unidirectional flow of air through
the lungs
 The birds respiratory
system delivers oxygen from the
air to the tissues and also removes
carbon dioxide

5.
Circulation
 Birds have four chambered hearts made of the right atrium,
right ventricle, left atrium and left ventricle
 The division helps for efficient flow of oxygenated and
deoxygenated blood
 Birds also have specific adaptations for flight, including a
larger heart relative to body weight and a faster heart rate

6.
Nervous system
 Highly developed nervous system,
includes brain and sense organs
 The nervous system integrates and
controls the various functions of the
body, while the sensory organs detect
the various stimuli in the bird's
environment
 The avian nervous system can be
divided into the central nervous system
(CNS) which comprises the brain and
spinal cord
 The peripheral nervous system (PNS)
which includes the cranial and spinal
nerves and ganglia

7.
Digestive System
 Birds have complete digestive
system
 The digestive order is as
follows: bill, mouth, tongue,
pharynx, esophagus, crop,
proventriculus, gizzard, small
intestine, caeca, rectum, cloaca.
 Alimentary canal contains gizzard
for crushing the food due to
absence of teeth.

8.
Excretory system
• The excretory system consists of the
two kidneys, each with a ureter that
carries the urine produced by the
kidneys to the cloaca where it leaves
the body
• Unlike mammals, do not have
separate exits for urine and feces.
Both waste products are eliminated
simultaneously through the cloaca
• Birds excrete nitrogenous wastes in
the form uric acid or guanine, which
reduces water loss

9.
Reproduction
 Birds reproduce by internal fertilization,
during which the egg is fertilized inside the
female
 All birds reproduce by laying eggs
 Eggs are produced inside the female and then
deposited in a nest
 Fertilized ovum then forms the nucleus of the
egg and the formation of the yolk, whites and
shell