Subject- Life science Topic- Support system in animals and plants Grade- 10-12

1. Ms. T.J. Mkhize
University of Johannesburg

2. There 3 types of skeletons
1. Hydrostatic skeletons- lack hard
parts)
2. Exoskeletons- external hard
parts
3. Endoskeletons- internal hard
parts

3.  A hydrostatic skeleton consists of fluid held
under pressure in a closed body.
 This is the main type of skeleton in most
cnidarians, flatworms, nematodes, and
annelids.
 Annelids use their hydrostatic skeleton for
peristalsis, a type of movement on land
produced by rhythmic waves of muscle
contractions.

4. NEMATODE FLATWORMS ANNELIDA

5.  An exoskeleton is a hard encasement deposited
on the surface of an animal
 Exoskeletons are found in most molluscs and
arthropods
 Arthropod exoskeletons are made of cuticle and
can be both strong and flexible
 The polysaccharide chitin is often found in
arthropod cuticle

6. MOLLUSC
ARTHROPODS

7.  An endoskeleton consists of hard supporting
elements, such as bones, buried in soft tissue.
 Endoskeletons are found in sponges,
echinoderms, and chordates.
 A mammalian skeleton has more than 200
bones.
 Some bones are fused; others are connected
at joints by ligaments that allow freedom of
movement.

8. SPONGES ECHINODERMATA CHORDATA

10. There are two type of human skeleton
1. Axial skeleton
2. Appendicular skeleton

11. Axial skeleton

12.  Consist of 28 bones
 It consists of flat bones that are connected on the
sides by immovable joints called sutures.
 In babies not all the bones of the skull make contact
with each other and fontanels are formed.
 The lower jaw bone (Mandible) is the only movable
bone of the skull – Upper jaw (Maxilla) is not
moveable.
 The large opening at the base of the skull is called the
foramen magnum – it is where the spinal cord enters
the skull.

14.  Consists of 33 bones called vertebrae.
 24 vertebrae are individual single bones.
 9 vertebrae are fused to form the sacrum and
coccyx.
 Cartilage disks are found between vertebrae.
 The s-shaped structure of the vertebral column and
the disks absorb shock and help to protect the
spinal cord.
 The first vertebrae – Atlas – carry the weight of the
skull, allows the head to nod.
 2nd vertebrae – Axis – allows head to move to the
side

15.  7 Cervical vertebrae
 12 Thoracic vertebrae
 5 Lumbar vertebrae
 5 fused vertebrae = sacrum
 4 fused vertebrae = coccyx

16.  Consists of the sternum, 12 pairs of ribs and
thoracic vertebrae.
 It protects the heart and lungs.
 First 7 pairs of ribs are directly attached to the
sternum by cartilage – called true ribs.
 Next 5 pairs – false ribs – last 2 pairs of false
ribs are not attached to the sternum – called
floating ribs
 Intercostal muscles found between ribs – aid in
breathing process.

17. True ribs
False ribs
sternum
Floating ribs

18.  Made up of the shoulder (pectoral
girdle), arms, hips (pelvic girdle)
and legs.
 126 bones.
 Function: Movement

21.  Support
 Movement
 Protection
 Blood cell production
 Storage
 Endocrine regulation

23.  The backbone of four - legged land vertebrates such as the
camel and the horse either curve upwards or downwards.
 The curve enables the backbone to withstand the heavy load
acting on the animal
 Big land animals such as elephant and the rhinoceros need
strong and big pectoral and pelvic girdles to support their
body weight
 . Big animals that have short legs with larger cross sections
are more stable and can also support a heavier load.

24.  The support system of aquatic vertebrates is not the same as
land vertebrates because life in water is very different from life on
land.
 Aquatic vertebrates such as whales and dolphins have smaller
and lighter endoskeletons than land vertebrates.
 This is because a large part of their body weight is supported
by water buoyancy. Water buoyancy helps aquatic animals to
move in water.

26.  The pelvic girdles of many aquatic vertebrates are
very small of non-existent.
 They are adapted only for swimming in water.
 Whales have small skeletons when compared to their
body size because a large part of their body weight is
supported by water buoyancy.

27.  Anas,M.(2012).Support and Movement.
http://www.slideshare.net/anasyem/support-and-movement1
 Campbell,N.A.,Reece,J.B. 2010.Biology Eighth Edition Pearson
International. 50-701-713.
 Unversiti Teknologi Malaysia.(2013). Support system in
animal.
http://www.slideshare.net/anasyem/support-and-movement1