ZOOLOGY STUDY GUIDE - Ye. O. Nevedomska - 2013

LECTURE 15. SUPERCLASS TETRAPODS, OR TERRESTRIAL VERTEBRATES (Tetrapoda). CLASS AMPHIBIANS (Amphibia)

1. Characteristics of terrestrial vertebrates

The characteristics of terrestrial animals include:

1. Overcoming gravity in the aerial environment is achieved through morphological adaptations and is accompanied by a general increase in metabolic rate.

2. Locomotion on land is performed by paired—fore and hind—jointed limbs with articulated connections, supported by strong musculature.

3. Intensive Respiration; gas exchange between the Organism and the environment occurs in the Lungs.

4. Morpho-physiological adaptations to reduce Water evaporation from the body surface.

5. Sensory Organs are adapted to function in the aerial environment: the respiratory and olfactory Regions of the Nasal cavity become separated, the Middle ear and eyelids develop, the shape of the eye lens changes, and the lateral line organs disappear (present only in amphibian larvae).

The superclass Tetrapoda, or terrestrial vertebrates, includes four classes:

1. Class Amphibia (Amphibians) — 4000 species.

2. Class Reptilia (Reptiles) — 7000 species.

3. Class Aves (Birds) — 9000 species.

4. Class Mammalia (Mammals) — 5000 species.

Due to The Nature of their development, the class Amphibia has much in common with fish and therefore belongs to the group Anamnia—anamniotes, whose eggs develop in water. An aquatic larva hatches from the egg and subsequently transforms into an adult through metamorphosis.

The classes Reptilia, Aves, and Mammalia are grouped into Amniota—amniotes, which are terrestrial vertebrates whose embryos, thanks to specialized membranes, can develop in an aerial environment. They diff

er in having an increased METABOLISM and a specific type of Water-Salt Metabolism.

Birds and mammals are capable of maintaining a relatively constant high body Temperature, which is why they are called warm-blooded (homeothermic or endothermic).