write chraracteristics Mammalia
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chraracteristics Mammalia (1). These animals are warm blooded, hairy and have mammary or milk producing glands, (mammary glands). They are the only animals which nourish their young ones with milk. There are about 4,000 species of mammals found in the world.
2. They are homoiothermous (warm blooded).
3. Oil glands (sebaceous glands) and sweat glands (sudoriferous glands) are present in the skin.
4. Teeth are of different types (heterodont) and are embedded in the sockets of jaws (the codont). These are developed twice during the life-time of the animal (diphyodont), milk and permanent teeth.
5. Except a few, mammals possess seven cervical (neck) vertebrae.
6. The skull is dicondylic i.e., with two occipital condyles.
7. Respiration is by lungs.
8. They possess a muscular diaphragm dividing trunk into thorax and abdomen.
9. The coelom is divided into four cavities; a pericardial cavity lodging the heart, two pleural cavities each containing the lung and an adominal cavity having the rest of viscera.
10. The heart is four chambered. Sinus venosus is absent. The red blood corpuscles are without nucleus. Renal portal system is absent.
11. The brain has large cerebrum and cerebellum. Optic lobes are divided into four lobes called corpora quadrigemina. Corpus callosum connects the two cerebral hemispheres internally.
12. 12 pairs of cranial nerves are present.
13. Each ear consists of three parts: external, middle and internal. Pinna is a part of external ear. Middle ear has 3 bony ear ossicles (malleus— hammer shaped, incus-anvil shaped and stapes-stirrup shaped). Internal ear has organ of Corti, the actual hearing organ.
14. Except egg laying mammals they are viviparous. There are present four embryonic membranes: chorion, amnion, allantois and yolk sac. Except egg laying mammals a well developed placenta is present.
15. Mammals occur in all sorts of habitats. They are dominant animals and are capable to learn because of their better developed brain.
2. They are homoiothermous (warm blooded).
3. Oil glands (sebaceous glands) and sweat glands (sudoriferous glands) are present in the skin.
4. Teeth are of different types (heterodont) and are embedded in the sockets of jaws (the codont). These are developed twice during the life-time of the animal (diphyodont), milk and permanent teeth.
5. Except a few, mammals possess seven cervical (neck) vertebrae.
6. The skull is dicondylic i.e., with two occipital condyles.
7. Respiration is by lungs.
8. They possess a muscular diaphragm dividing trunk into thorax and abdomen.
9. The coelom is divided into four cavities; a pericardial cavity lodging the heart, two pleural cavities each containing the lung and an adominal cavity having the rest of viscera.
10. The heart is four chambered. Sinus venosus is absent. The red blood corpuscles are without nucleus. Renal portal system is absent.
11. The brain has large cerebrum and cerebellum. Optic lobes are divided into four lobes called corpora quadrigemina. Corpus callosum connects the two cerebral hemispheres internally.
12. 12 pairs of cranial nerves are present.
13. Each ear consists of three parts: external, middle and internal. Pinna is a part of external ear. Middle ear has 3 bony ear ossicles (malleus— hammer shaped, incus-anvil shaped and stapes-stirrup shaped). Internal ear has organ of Corti, the actual hearing organ.
14. Except egg laying mammals they are viviparous. There are present four embryonic membranes: chorion, amnion, allantois and yolk sac. Except egg laying mammals a well developed placenta is present.
15. Mammals occur in all sorts of habitats. They are dominant animals and are capable to learn because of their better developed brain.
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hey mate!......
▪ Thediaphragm is a muscle that separates the thoracic cavity from the abdominal cavity.
▪ Seven cervical vertebrae (neck bones) are present in most mammals.
▪Most are viviparous though some are oviparous. An extended gestation period uterine development is common in most placental mammals.
▪ Teeth are imbedded in the jaw bone and come in a variety of forms.
▪ Well developed brain.Mammals developed from the therapsid ancestors during the Triassic period.
▪Mammals are heterodontic, meaning that their teeth are different shapes, except those with no teeth at all.
▪ Reptiles and fish have teeth that are all basically the same, though they can vary in size throughout the mouth. See image above.
▪The Buccal Cavity has a false palate as a roof, meaning that the nostrils do not lead directly into his mouth.
▪ The body is maintained at a constant temperature they generate heat within their bodies metabolically and also have special cooling mechanisms.
▪Tectum reduced to corpora quadrigemina: functions mainly as a relay center for auditory information and to control visual reflexes.
《 HOPE IT HELPS U DEAR 》.......
▪ Thediaphragm is a muscle that separates the thoracic cavity from the abdominal cavity.
▪ Seven cervical vertebrae (neck bones) are present in most mammals.
▪Most are viviparous though some are oviparous. An extended gestation period uterine development is common in most placental mammals.
▪ Teeth are imbedded in the jaw bone and come in a variety of forms.
▪ Well developed brain.Mammals developed from the therapsid ancestors during the Triassic period.
▪Mammals are heterodontic, meaning that their teeth are different shapes, except those with no teeth at all.
▪ Reptiles and fish have teeth that are all basically the same, though they can vary in size throughout the mouth. See image above.
▪The Buccal Cavity has a false palate as a roof, meaning that the nostrils do not lead directly into his mouth.
▪ The body is maintained at a constant temperature they generate heat within their bodies metabolically and also have special cooling mechanisms.
▪Tectum reduced to corpora quadrigemina: functions mainly as a relay center for auditory information and to control visual reflexes.
《 HOPE IT HELPS U DEAR 》.......
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