Presentation 3 Comparative biology

T ask 1 In the animal kingdom three different skeletons occur: hydrostatic skeleton, exoskeleton and endoskeleton. Which type of the skeleton relates to the following descriptions and pictures?

a) b) c)

………………………… occurs in many soft-bodied animals, such as earthworms. It is a cavity filled by pressurized fluid. By manipulating the pressure in different parts of the cavity, many soft-bodied animals can change shape and produce considerable force. Earthworms can burrow through soil using pressure.

………………………… is a hard, nonliving structure that encloses the rest of the body. It may consist of a single hard piece, like the shell of a snail, or it may have two or more hard pieces linked together by flexible tissue, as in a clam. In crustaceans, insects, spiders and also in some other groups of animals, this type of skeleton is called a cuticle. These skeletons have the advantage of providing protection from predators. One disadvantage, however, is that it restricts the growth of the animal inside it.

………………….. are enclosed in other tissues. The human skeleton does not offer much protection from predators, but it does a good job of keeping the body from collapsing into a helpless pile. It also provides sites for attachment of muscles.

Task 2 Word formation. In the above text find 3 biology terms formed by means of compounding.

1. ........................................ b) ........................................ c) ...............................................

Task 3 What animals are mentioned in the above text?

1. ........................... b) .............................. c) ............................. d) ..................................

5. ………………….

UNIT 12 THE RESPIRATORY AND DIGESTIVE SYSTEMS

Presentation 1 The respiratory system

Task 1 Complete the first paragraph of the below text describing three steps of respiration.

The primary function of the respiratory system is to supply the blood with .................... It is done through breathing. When we breathe, we inhale .................... and exhale ...................... Respiration is a sequence of events that results in gas exchange between the body cells and the environment. In terrestrial vertebrates, respiration includes these steps:

• Ventilation: includes inspiration (entrance of air into the lungs) and expiration (.........................................................................................).

• External respiration: gas exchange between the air and the blood within the ............ . The blood then transports oxygen from the ............................ to the ........................... .

• Internal expiration: ..........................................................................................................

Respiration is achieved through the nasal cavity, oral cavity, the trachea, lungs and diaphragm. Oxygen enters the respiratory system through the nose and the mouth, then passes through the larynx and the trachea which is a tube leading into the thoracic cavity where it splits into two smaller tubes called bronchi. Each bronchus then divides again into the bronchial tubes (bronchioles) that lead directly into the lungs and end there at small bags called alveoli where the gas exchange takes place.

Task 2 Complete the picture with these terms:

bronchi, bronchioli, larynx, trachea,

alveoli, nasal cavity, lungs, lobes,

oral cavity, diaphragm

Task 3 Write synonyms (Latin terms) next to the

colloquial expressions:

1. voice box: .............................

2. mouth:...................................

3. wind pipe: .............................

4. nose: ......................................

5. breathing: ..............................

6. breathe in: .............................

7. breathe out: ...........................