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Presenters : Pema Khandu Phub Lhamo Tshering Lhamo

You may know that you are related to apes and monkeys. But did u know that you are also related to bats, tigers, whales, kangaroos, and many more creatures? “ Mammals ”. Presenters : Pema Khandu Phub Lhamo Tshering Lhamo.

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Presenters : Pema Khandu Phub Lhamo Tshering Lhamo

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  1. You may know that you are related to apes and monkeys. But did u know that you are also related to bats, tigers, whales, kangaroos, and many more creatures? “Mammals” Presenters: PemaKhandu PhubLhamo TsheringLhamo

  2. Describe different classes of mammal with examples Kingdom Animalia---Phylum Chordata------Subphylum Vertebrata---------Class Mammalia

  3. What is mammals? • Mammals are animals that have hair, are warm-blooded, and nourish their young with milk. General characteristics of mammals • Warm blooded animals. • Skin is more or less covered with hairs except Cetacea. • Sudoriporous (sweat) glands and sebaceous (oil) glands are present in the skin. • Mammary glands in females to nourish the young ones. • External ear (pinnae) are present.

  4. Teeth are heterodont (differentiated into incisors, canines and molars), thecodont (embedded in the alveolar pockets of jaws) and diphyodont (only 2 sets of teeth, milk set replaced by permanent set). • Skull with two occipital condyles which are formed entirely by exoccipitals. • The lower jaw is composed of a single bone, on each side • Vertebrae are gastrocentrous composed of three pieces, the centrum, and two epiphyses.

  5. With few exceptions mammal possess seven cervical vertebrae. • The digits in the fore and hind limbs are never more than 5, but often reduced. • Presence of muscular diaphragm between thoracic and abdominal cavities. • Heart is four chambered with only one left aortic arch. • RBC are non-nucleated. • Brain with four optic lobes. • Kidney is metanephros. • Penis is always present. • Viviparous (the young develops in the uterus for some time and born alive).

  6. Three classes of Mammals • Prototheria (Monotremes): are primitive egg-laying mammals. • Metatheria (Marsupials/pouched mammal): their young are born in an extremely immature state. • Eutheria (Placental mammals): their young are born at an advanced state.

  7. Prototheria(Egg laying mammal) • Primitive mammals • Connecting link between the reptile and mammal General characteristics • Skeleton resembles that of reptile • No external pinna present on the ear • Teeth are present only in the young, adults with horny beak • A cloaca is present into which ureters and urinogenitals sinus open • Mammary glands are without nipples • The pectoral girdle possesses large coracoid bones and interclavicle

  8. The pelvic girdle possesses epipubic bones extending from the pelvis • Vertebrate are without epiphyses • The ribs have only a single head, the tuberculum being absent • In the skull , tympanic bulla and lacrimals are absent ; the jugal is reduced or absent • There is no corpus callosum in the brain • The cochlea is a simple process of the sacculus and not coiled • Testes are abdominal • Females are oviparous • Found in Australia, Tasmania and New Guinea

  9. Examples of prototheria Echidna (spiny ant eater) Ornithorhynchus (Duck-billed platypus)

  10. Metatheria(pouched mammals) General characteristics • Young ones are born prematurely after very short gestation • Marsupium or rood pouch is present in the females • Mammary glands are sebaceous and bearing nipples • Epipubic (marsupial) bones are usually present and attached with the pubis • Separate coracoid and interclavicle are absent • Ribs bear two heads, tuberculum and capitulum

  11. Vertebrae with epiphyses • Corpus callosum is feebly developed or absent. • Vagina and uterus are double (didelphic condition) • Viviparous • Placenta is usually absent. Examples Didelphis (Opossum) Dasyurus (Tiger-cat)

  12. Eutheria Placental mammal General characteristics • Give birth to young one • Marsupium (marsupial pouch) is entirely absent. • Mammary glands are well developed with nipples. • Epipubic bones are absent. • Ribs bear two heads, tuberculum and capitulum. • Clooca is absent. • Corpus callosum is present • Urinogenital organs open independently of the rectum. • Testes are usually contained in scortal sacs.

  13. Warm blooded • External pinna present • Viviparous. • The young always nourished for a considerable time in the uterus by means of allantoicplacenta and born in a relatively advanced state.

  14. Examples • Insectivorous mammal- shrew,moles • Aerial mammal – bat • Aquatic mammal-whales • Carnivorous mammal-tiger • Hoofed mammal- horse • Mammal with proboscis-elephant • Primates-apes, monkeys

  15. References Verma, P.S. (1984). A manual of Practical Zoology: Chordates. New Delhi: S. Chand & Company Ltd. Newman, H.H. (1981). The Phylum Chordata. Agra, India : Satish Book Enterprise.

  16. Thank you !

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