Displaying articles by tag: Zoology

Dayyal Dg. in Zoology
Sunday, 11 February 2018 09:35 Featured

TORSION AND DETORSION IN MOLLUSCA

TORSION   Torsion is a process in which the viscero-pallium rotates anti-clockwise through 180° from its initial position during larval development. So that the mantle cavity, with its pallial complex, is brought to the front of the body in the adult.   How Torsion Occurs   Torsion is not an…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Torsion in Mollusca
  • Detorsion in Mollusca
  • How Torsion Occurs In Mollusca
  • Torsion and Coiling
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Dayyal Dg. in Zoology
Tuesday, 06 February 2018 14:42

PROCESS OF FORMATION OF PEARL IN MOLLUSCS

The “pearl” is literally formed by the mantle epithelium, which becomes deposit around any external body or particles, these external particle or body invade in between the shell and mantle in any way. Pearl is secreted by the mantle as a means of protection against a small external particle. When…

  • Process of Pearl Formation In Molluscs
  • Why Do Oysters Make Pearls
  • How are Pearls Harvested
  • How Long Does It Take To Make a Pearl
  • Pearls Formation In Molluscs
  • Formation of Pearl in Molluscs
  • Zoology
  • Zoology Notes
  • Article
  • How to
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BS Media in Zoology
Monday, 10 July 2017 13:59

COMPARATIVE ANATOMY: PECTORAL GIRDLE OF REPTILE, BIRD AND MAMMAL

The pectoral girdle is connected to the vertebral column through muscles and ligaments. The pectoral girdle consists of two similar halves and each half is formed by three bones namely dorsal, ventral and antero ventral. The dorsal bone is known as scapula, the antero ventral bone is called clavicle and…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Comparative Anatomy
  • Pectoral Girdle of Reptile
  • Pectoral Girdle of Bird
  • Pectoral Girdle of Mammal
Read 17178 times
BS Media in Zoology
Sunday, 09 July 2017 21:02

COMPARATIVE ANATOMY: PECTORAL GIRDLE OF FISH AND FROG

The skeletal system or skeleton includes the hard parts of the animal body. All the vertebrates possess the endoskeleton (inside the body). These are the living tissues develop from the interior layers of mesoderm of the body. The term skeleton denotes the endoskeleton in vertebrates. Skeleton plays a very important…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Comparative Anatomy
  • Pectoral Girdle of Fish
  • Pectoral Girdle of Frog
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BS Media in Zoology
Sunday, 09 July 2017 19:09

COMPARATIVE ANATOMY: RESPIRATION IN BIRDS, REPTILES AND MAMMALS

Comparative anatomy of respiratory systems in calotes (lizard), columba (pigeon) and oryctolagus (rabbit). Calotes is a poikilothermic terrestrial lizard. It is commonly known as garden lizard. Columba and oryctolagus are homoiothermic animals. Columba is commonly known as pigeon adapted for aerial mode of life. Oryctolagus is herbivorous mammal. It is…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Respiration in Birds
  • Respiration in Reptiles
  • Respiration in Mammals
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BS Media in Zoology
Sunday, 09 July 2017 14:32

COMPARATIVE ANATOMY: RESPIRATORY ORGANS OF FISH (SCOLIODON) AND FROG (RANA)

Scoliodon (fish) is a poikilothermic cartilaginous fish. It is commonly known as shark. Rana (frog) is an amphibian and poikilothermic animal. It is commonly called as frog.   Living cells require energy for performing metabolic activities. This energy is provided by the oxidation of food materials present within the cells.…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Comparative Anatomy
  • Respiratory Organs in Fish
  • Respiratory Organs in Frog
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BS Media in Zoology
Sunday, 09 July 2017 12:53

COMPARATIVE ANATOMY: DIGESTIVE SYSTEM OF BIRD, MAMMAL AND REPTILE

Digestive System Of Bird: Eg: Pegion Digestive System (Columba) Digestive System Of Mammal: Eg: Rabbit Digestive System (Oryctolagus) Digestive System Of Reptile: Eg: Lizard Digestive System (Calotes) In previous topic we discussed about the comparative anatomy of digestive system of frog and shark. In this topic we discussed about the…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Comparative Anatomy
  • Digestive System of Bird
  • Digestive System of Mammal
  • Digestive System of Reptile
Read 18784 times
BS Media in Zoology
Saturday, 08 July 2017 12:52

COMPARATIVE ANATOMY: INTEGUMENT IN REPTILES, BIRDS AND MAMMALS

Comparison Of Integument Derivatives In Calottes (Reptile), Columba (Bird) And Oryctolagus (Mammal) Calotes is a terrestrial Reptile (lizard). Columba is flying bird. Oryctolagus is a herbivorous mammal. All these animals are grouped under Amniota and columba & oryctolagus are warm blooded animals. The integument forms the outermost covering of the…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Comparative Anatomy
  • Integument in Reptiles
  • Integument in Birds
  • Integument in Mammals
Read 18911 times
BS Media in Zoology
Saturday, 08 July 2017 11:54

COMPARATIVE ANATOMY: INTEGUMENT IN SCOLIODON AND RANA

COMPARATIVE ACCOUNT OF THE INTEGUMENT (SKIN) IN THE SCOLIODON (SHARK FISH) AND RANA (FROG) Scoliodon and Rana are poikilothermic animals. Scoliodon is an aquatic cartilage fish. Rana lives in water and on land-amphibian. In both the vertebrates the skin (integument) is the outermost covering of the body. It is multicellular…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Comparative Anatomy
  • Integument in Scoliodon and Rana
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BS Media in Zoology
Friday, 07 July 2017 19:17

GONADS OF HERDMANIA

Herdmania is a bisexual animal. It is a protogynous animal. Ovary matures’ first. Hence cross fertilization takes place.   Herdmania contains a pair of gonads. The left gonad lies in the intestinal loop above the heart. Each gonad shows 10 to 25 lobes arranged in two rows. The median lobe…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Herdmania Gonads
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BS Media in Zoology
Friday, 07 July 2017 19:03

ORGANISATION OF HERDMANIA TADPOLE LARVA

Herdmania is a hermaphrodite animal. The fertilised eggs undergo holoblastic unequal clevage and it develops into blastula. it shows upper micromeres and lower macromeres. By invagination of the macromeres gastrulation takes place and gastrula is formed. This gastrula develops into a tailed larva called Ascidian Tadpole larva. (Herdmanis life history,…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Organisation of Herdmania Tadpole Larva
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BS Media in Zoology
Friday, 07 July 2017 14:47

RETROGRESSIVE METAMORPHOSIS IN HERDMANIA

During metamorphosis the larva will loose all the chordate characters and attains an invertebrate like form. This type of metamorphosis, where highly advanced larval form ends in a lowly organised adult is called retrogressive metamorphosis.   Fixation of the larva: The larva swims for some time without feeding. It is…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Metamorphosis in Herdmania
  • Retrogressive Metamorphosis in Herdmania
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BS Media in Zoology
Friday, 07 July 2017 14:32

HERDMANIA: SPICULES IN THE TEST

In the test of Herdmania two types of calcareous spicules are Present. They are:   Microscleres: These are 40 to 80 microns in length. They are minute. Megascleres: These are long spicules. They show different shapes. They are 1.5 to 3.5 mm in length. They are two types.a) Spindle shaped…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Herdmania Spicules
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BS Media in Zoology
Friday, 07 July 2017 13:44

EXCRETORY ORGAN OF HERDMANIA

A neural gland is present above the brain in herdmaina. It is brown in colour. It is present in the mantle. It is 4mm in diameter. It show branching tibuIes. At one end it leads into a short duct which opens by ciliated funnel above the dorsal tubercle. In the…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Excretory Organs of Herdmania
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BS Media in Zoology
Friday, 07 July 2017 13:29

NERVOUS SYSTEM OF HERDMANIA

Herdmania shows brain or nerve ganglion. It is 4 mm long. It is present in the mantle in between the two siphons. A neural gland is present above the brain. From the brain three nerves arise, one goes to the bronchial siphon, and two will go to the atrial siphon.…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Nervous System of Herdmania
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BS Media in Zoology
Friday, 07 July 2017 13:09

EXTERNAL CHARACTERS OF HERDMANIA

Herdmania is a simple ascidian, In Indian ocean this genus is represented by 4 species.   1. Herdmania pallida 2. H. ennurensis 3. H. mauritiana 4. H. ceylonica   Herdmania belongs to,   Phylum: Chordata Sub-phylum: Urochordata Class: Ascidiacea Order: Pleurogona   Herdmania is a marine and sedentary animal. It…

  • Zoology
  • Zoology Notes
  • Notes
  • Article
  • Characters of Herdmania
  • External Characters of Herdmania
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