Table of Contents
Mammalia General Characteristics, Classification and Examples
After reading this article you will learn about Mammalia General Characteristics, Classification and Examples
Mammalia General Characteristics
- The mammals are cosmopolitan and found in terrestrial, aquatic and aerial
- Most unique mammalian character is presence of mammary glands
- Mammals are warm blooded or homeothermic animals
- Body is divided into head, neck, trunk and tail
- Body is fully or partially covered with hairs
- Limbs are two pairs, pentadactyl. adapted for various modes.
- Skins are thick and glandular. So many types of glands are present in the skin as sweat glands, sebaceous glands and mammary glands
- The diaphragm is present in between thorax and abdomen of all the members
- Alimentary canal is complete. anus and urinogenital apertures are separate. Cloaca is absent.
- Teeth heterodont (different types), thecodont (embedded in sockets) and diphyodont (grow twice).
- Larynx or sound organ is found in the neck region
- Respiration is by lungs & Excretion by kidneys
- External ear with ear pinna. middle ear with there ear ossicles
- Presence of 7 cervical vertebrae
- Brain highly developed. cranial Nevers 12 pairs. corpus callosum help for connecting cerebral hemisphere
- Mammals are unisexual. testis outside in testis sac in male.
- Fertilisation is internal. foetus nourishes through placenta.
- Mostly mammals are viviparous, which give birth to young once.
Classification of Mammalia
Mammalia has the largest class in the animal kingdom. Based on their reproduction, they are classified into three subclasses: Eutheria, Metatheria and Prototheria
Subclass 1. Prototheria
- No pinna
- No nipples
- DS & Urinogenital tracts open into cloaca
- No scrotum
- No placenta
- E.g. Ornithorhynchus, Echidna etc.
Subclass 2. Metatheria
- Pinna present
- Nipples abdominal
- DS & Urinogenital tracts open control by common sphincter
- Scrotum in front of penis
- Placenta less developed
- E.g. Macropus, Didelphis etc.
Subclass 3. Eutheria
- Pinna present
- Nipples abdominal or thoracic
- Digestive and urinogenital tracts open out separate
- Scrotum behind penis
- placenta well developed
- E.g. Apes, Balaenoptera etc.
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