INTRODUCTION. 1. It is a common fresh water polyp. 2. In 1774 it was first recognized by Trembley 3. C. Linnaeus named it Hydra. 4. It is a remarkable.

Presentation on theme: "INTRODUCTION. 1. It is a common fresh water polyp. 2. In 1774 it was first recognized by Trembley 3. C. Linnaeus named it Hydra. 4. It is a remarkable."— Presentation transcript:

1 HYDRA Abul Kalam Rashad Ahmed Lecturer in Zoology Rajshahi Cadet College

2 INTRODUCTION. 1. It is a common fresh water polyp. 2. In 1774 it was first recognized by Trembley 3. C. Linnaeus named it Hydra. 4. It is a remarkable animal.

3 NAMING OF HYDRA. 1. It is resembled an ancient mythological Greek Monster-Hydra, which could recover its head as soon as it was cut off. Hercules killed it later on. SPECIES OF HYDRA. 1. H. vulgaris. 2. H. oligactis. 3. H. gangetica. 4. Chlorohydra viridissima.

4 HABIT AND HABITAT 1. Hydra usually attached with submerged vegetation. 2. In winter it is available. 3. It lives on insects or insect larvae and small crus taceans. 4. It is found in fresh water. 5. It is solitary in habit.

5 HABITAT. 1. Hydra founds in ponds, ditches, lakes, streams. 2. Hydra is found in marsh, creek, rivers, and their tributaries.

6 1. Diploblastic animal. 2. Triploblastic animal. 3. Distinction between diploblastic and triploblastic animal. 4. External morphology. a) Hedd, b) Basal disc, c) Mouth, d) Bud e) Tentacles, f) Body, g) Testis, h) Ovary

7 HISTOLOGY OF HYDRA 1. EPIDERMIS. a) Epitheliomuscular cell
b) Interstitial cell c) Sensory cell d) Nerve cell e) Gland cell f) Germ cell g) Cnidoblast

8 Internal Structure of Hydra
Mouth Coelenteron Tentacles Gastrodermis Hypostome Mesogloea Epidermis Nematocyst Fig: T.S. of Hydra Mesogloea Epidermis Gastrodermis Interstitial Pseudopodial Cnidoblast Nerve cell Sensory Cell Gland cell Gland cell Musculo-epithelial Mesogloea Flagellated cell Interstitial cell Gastrodermis Epidermis Fig: Histology of body wall in Hydra Bud Thread Barbule Operculum Cnidocil Coelenteron Barb Nematocyst Basal disc Thread Fig: L.S. of Hydra Nucleus Fig: Cnidoblast at rest and with nematocyst discharged

9 Fig: Ectodermal cells in Hydra
Mucous Interstitial cell Cnidoblast cell Sensory cell Musculo-epithelial Nerve cell Fig: Ectodermal cells in Hydra

10 NEMATOCYST. 1. Penetrant / Stenotele 2. Volvent / Desmoneme 3. Glutinant a) Stereoline glutinant b) Streptoline glutinant

11 GASTRODERMIS Gastrodermis : The cell of gastrodermis are produced from the germinal endoderm. It is composed of the following cells : 1. Nutritive- muscle cell. a) Pseudopodial nutritive cells b) Flagellated Nutritive cells 2. Interstitial cells. 3. Nerve cells . 4. Sensory cells . 5. Gland cells. a) Mucous secreting gland cells. b) Enzyme secreting gland cells.

12 3. MESOGLOEA. 4. COELONTERON. 5. Diff. Between Epidermis and Gastrodermis 6. Diff. Between Coelenteron and Coelom. 7. Functions of all cells. 8. Dig. Of all cells.

13 FOOD, FEEDING, AND PROCESS OF DIGESTION
NUTRITION. 1. Definition. 2. Stages. a) Foods. B) Ingestion . C) Digestion d) Absorption. E) Assimilation. f) Egestion. FOOD. 1. Insect larvae , 2. Arthropods . 3. Cyclops. 4. Daphnia . 5. Fish eggs . 6. Nematodes. 7. Rotifers.

14 Description of the following points will be given :
1. Process of food intake. 2. Digestion. a) Extracellular digestion. b) Intracellul;ar digestion. 3. Absorption. 4. Assimilation. 5. Egestion.

15 LOCOMOTION Definition : The special process by which an organism changes its position respond to various environmental stimuli , is known as locomotion. Types of locomotion. 1. Looping. 2. Somersaulting. 3. Gliding Walking. 5. Swimming. 6. Climbing. 7. Floating Drowning. 9. Spontaneous

16 REPRODUCTION Definition : The process by which two opposite sex mate together and produce same species to maintain their own existence and continuity of the race is called reproduction.

17 Type. 1. Asexual reproduction. a) budding . B) Fission. 2. Sexual reproduction. a) Formation of gamete. 1. Spermatogenesis. 2. Oogenesis. 3. Fertilization. 4. Development.

18 Development. 1. Morula phase. 2. Blastula phase. 3. Gastrula phase. 4. Hydrula. Regeneration of Hydra. Immortality of Hydra.

19 Fig: Life cycle of Hydra
Adult Hydra Ovary Testis Ovary Oogonia Mesogloea Testis Mesogloea Dev. Of sperm Spermatogonia Spermatocyte Young Hydra Egg Cyst Fertilization Ectoderm Endoderm Sperm Mesogloea Cyst wall Cleavage Hydrula Endodermal cells Archenteron Gastrula Fig: Life cycle of Hydra Blastula

20 DIVISION OF LABOUR IN HYDRA
1. Epitheliomascular cell. 2. Interstitial cell. 3. Cnidocyte cell. 4. Sensory cell. 5. Nerve cell. 6. Gland cell. 7. Nutritive cell. 8. Oral pore. 9. Coelenteron 10. Tentacles Pedal disc.

21 SYMBIOSIS Definition. The process by which two organisms are living together and both of them get benefit from each other is called symbiosis. Type. 1. Mutualism. 2. Parasitism. 3. Commensalism.