The document discusses the skeletal system as a fundamental framework for vertebrates, highlighting its functions, types, and evolutionary adaptations. It details different skeletal types such as exoskeletons, hydrostatic skeletons, and endoskeletons, as well as the role of joints and various bones in providing support, movement, and protection. The content also emphasizes the importance of the skeletal system in relation to organ protection, mineral storage, and blood cell production.

1. SKELETAL
SYSTEM

2. 01
A Spectrum of Support
03
A Framework for Movement
02
Table of contents
Types of Skeletons
The Axial and Appendicular
Skeleton
The Endoskeleton

3. 04
05
Table of contents
Functions of the Skeletal
System
Adaptations and
Evolution

4. INTRODUCTION
The skeletal system serves as the
fundamental framework for all vertebrates,
providing support, structure, and protection
for the body. This presentation will delve into
the diverse ways animal skeletons are
designed to meet the unique needs of different
species. The skeletal system is the 'framework'
upon which the body is built – it provides
support, protection and enables the animal to
move. The joints are considered to be an
integral part of the skeleton. The skeletal
system is made of the specialized connective
tissues, bone and cartilage

5. What is the origin of
bones in animals?
Bones in animals originate from mesoderm-derived
mesenchymal cells and undergo a process involving three
stages: membranous period, cartilaginous period, and bony
period. The skeletal system, consisting of bones and cartilage,
plays a crucial role in providing structure, protecting organs,
allowing movement, storing minerals, producing blood cells,
and storing fats. The evolution of the skeletal system provides
insights into the classification and characteristics of different
animal groups. Before the establishment of the concept of
evolution, two types of bones were recognized in vertebrates
based on their embryonic development. Evolutionary processes,
as evidenced by the fossil record, show the transition from early
bony fish to modern ray-finned and lobe-finned fish, which
eventually led to species capable of moving out of the water.
Understanding the evolutionary developmental biology of
vertebrate skeletal tissues is essential for comprehending the
interconnectedness of somite and vertebral patterning and the

6. A Spectrum of Support
Types of Skeletons

7. Why is it
important?
The types of skeletons in animals are
important for several reasons, as they
play a critical role in their structure,
movement, and survival. Here are a few
key reasons:
● Protection of Vital Organs
● Movement and Mobility
● Adaptation and Evolution
● Growth and Development
● Support and Structure

8. Exoskeleton
Hydrostatic
Skeleton
An exoskeleton is an
external, hard covering that
protects the animal and
provides support. This is
common in arthropods like
insects, crabs, and lobsters.
This type relies on internal
fluid pressure within closed
chambers to provide support
and shape. It is prevalent in
soft-bodied animals like
jellyfish and earthworms.
TYPES OF SKELETON

9. Endoskeleton
An endoskeleton is an internal
framework composed of bones
or cartilage. This type is found
in vertebrates, including
mammals, birds, reptiles,
amphibians, and fish.
TYPES OF SKELETON

10. BONES
These rigid structures
provide strength and
support, protecting vital
organs and serving as
attachment points for
muscles
A flexible connective
tissue found in joints,
ears, and nose, cartilage
provides cushioning and
reduces friction.
These strong, fibrous
tissues connect bones to
bones, stabilizing joints
and limiting their range
of motion.
These tough, fibrous
cords connect muscles
to bones, transmitting
force and enabling
movement.
ENDOSKELETON
LIGAMENTS
CARTILAGE
TENDONS

11. Appendicular
Skeleton
Axial Skeleton
This section comprises the
limbs (arms and legs) and
their connecting structures,
such as the shoulder and
pelvic girdles. It allows for
movement, locomotion, and
manipulation of the
environment..
This central core includes the
skull, vertebral column, ribs,
and sternum. It protects vital
organs and provides support
for the body.
The Axial and Appendicular Skeleton

12. Functions of the Skeletal System
The skeleton provides a
rigid framework that
supports the body and
protects vital organs.
Bones act as levers, and
muscles attached to
them generate force to
produce movement.
The process of blood cell
formation takes place in
the bone marrow,
producing red blood
cells, white blood cells,
and platelets.
Bones serve as a
reservoir for essential
minerals like calcium and
phosphorus, which can
be released into the
bloodstream as needed.
Support and
Protection Movement Hematopoiesis
Mineral Storage

13. SPONGY BONE
COMPACT BONE
This dense, hard tissue forms
the outer layer of most bones,
providing strength and
support.
TYPES OF BONES
This less dense, porous
tissue is found inside bones,
providing flexibility and
housing bone marrow.

14. CARTILAGE
This flexible, smooth tissue
covers the ends of bones,
reducing friction at joints and
allowing for smooth
movement.
TYPES OF BONES

15. Cartilaginous
joints
Fibrous joints
These joints have limited
movement, with cartilage
connecting the bones. The hip
bone is an example.
These joints are immovable,
held together by strong
connective tissue. The skull
is an example of a fibrous
joint.
JOINTS

16. Synovial joints
These joints allow for free
movement, with a fluid-filled
cavity that reduces friction.
Synovial joints are further
categorized into five types.
JOINTS
• Ball-and-socket joints: These
joints allow for movement in
multiple planes, such as the
shoulder joint.
• Hinge joints: These joints allow
for movement in one plane, like
the knee or elbow.
• Gliding joints: These joints allow
for limited sliding movement, like
the wrist.
• Pivot joints: These joints allow for
rotation around a central axis, like
the head turning side to side.
• Compound joints: These joints
involve multiple bones and joints,
allowing for a variety of
movements, like nodding the

17. Adaptation
s and
Evolution

18. BIRDS
Their lightweight bones, hollowed-out
for air sacs, allow for flight.

19. Their streamlined skeletons,
often with flexible cartilage,
enable efficient swimming.
FISH

20. Their diverse skeletal structures
reflect their varied habitats and
modes of locomotion.
MAMMALS

21. WHY DO WE HAVE SKELETONS?
A skeleton protects our organs, such as our brain, heart
and lungs.
A skeleton keeps us upright.
A skeleton helps us to move.

22. Fun facts about
Skeletons

23. A fish has a long
flexible spine to help it
swim. The bones in
the fins help propel
the fish through the
water.
FISH

24. A dog’s shoulder
bones are designed to
be able to support the
weight of its upper
body. The joints in the
leg bones are flexible
to help the dog run.
DOG

25. Snakes can have over 300
vertebrae (sections of back
bone) with a rib attached to
each one. This allows snakes
to be flexible and slither
along the ground.
SNAKES

26. VERTEBRATES AND INVERTEBRATES
Animals with spines (backbones) are called vertebrates.
• Mammalia ( Mammals)
• Aves (Birds)
• Reptilia (Reptiles)
• Amphibia (Amphibians)
• Agnatha (Jawless Fish)
• Osteichthyes (Bony fish)
• Chondrichthyes (Cartilaginous fish)
Some animals don’t have spines. They are called invertebrates.
• Earthworms
• Jellyfish
• Snails

27. THANK YOU!