Supporting Systems Flashcards
Name and explain the three types of skeletons
- Hydro skeleton - consists of fluid filled, closed chambers within an organism
- Exoskeleton- surrounds the body of an organism
- Endoskeleton - occur within the body of an organism
how do animals with a hydrostatic skeleton move
the fluid filled closed chambers provide support against which muscles can contact to bring about movement, the contracting creates pressure that causes a change in shape of the animal, this causes movements such as crawling, burrowing or swimming
give examples of animals that have hydrostatic skeletons
- coelenterates, eg. jellyfish
- annelids eg. earthworms
- nematodes eg. roundworms
What are the disadvantages of an hydrostatic skeleton
- they like well-developed skeletal depends mechanisms
- have a restricted range of movement
- are confined to areas near or in water
- cannot reach any great size
Give examples of animals that have exoskeletons
• Tortoises • coral • starfish • molluscs but Mainly found in arthropod
In arthropods what is the exoskeleton made from
it is made from the polysaccharide, chitin, which is a substance similar to the cellulose found in plant walls. it is light and strong
What are the advantages of an arthropod exoskeleton
- It’s an external structure that supports the animal and protect internal organs
- It has muscles attached to knobs and plates to allow for movement
- It has joints where the exoskeleton is thin and flexible which enables the animal to move more easily
- It is often covered with a layer of wax called a cuticle that reduces loss of water from the body which prevents the animal from drying out
What are the disadvantages of exoskeletons
- Limited mobility due to their rigidity
* Limited growth as a large animal would need a large exoskeleton that would be very heavy and restrict movement
How are the growth disadvantages of exoskeletons overcome
- arthropod shed their exoskeletons to allow them to grow this is called moulting or ecdysis. A new exoskeleton is generated by the underlying epidermis. after the exoskeleton is shed, the arthropod pumps up its body by the intake of air or water in order to expand the new exoskeleton to a larger size. Dehydration of the cuticle then takes place which causes it to harden into an exoskeleton
- many mollusks have calcareous shells and as the grow the diameter of shell is added to and enlarged without altering shape
How are the mobility disadvantages of exoskeletons overcome
- the arthropod exoskeleton is divided into functional units. egg the head, thorax and abdomen of insects
- arthropoda have jointed limbs where the exoskeleton is thin which enables the leg to move
what are vertebrate endoskeletons made of
either bone or cartilage
What are the advantages of an endoskeleton
- supports the body giving it shape
- is made of living tissue which can grow as the animal increases in size
- protects the internal organs such as the brain, lungs and heart
- provides anchors for muscles which work with bones to allow movement
What two things make up the endoskeleton
Bone and cartilage
Where it does Cartlidge occur
In isolated areas of the body such as in parts of the ribs, the nose, pinna of the ear, between vertebra and in the lining of joints
What is the difference between cartilage and bone
Cartilage is much softer than bone because it contains less minerals it has a few blood vessels and no nerves