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In male shark claspers are present. The claspers are rod like copulatory organs present on the inner borders of the pelvic fins. They are supported by carfilages. Each clasper has a groove on its dorsal side. The groove is opened at both the ends. Its anterior opening is called the…
In Scoliodon the olfactory lobes are olfactory organs or nasal sacs. They are present in the olfactory sacs of cranium. They develop from the ectoderm. They open out through the exterior by external nostrils. Each nostril is divided into two parts. In current siphon and excurrent siphon. …
On the lateral sides of think and tall lateral line canals are present. They are present deeply In the dermis. In the head region there are connected by transverse canals. In the head region cephalic canals are present Infra orbital Supra orbital Hyo mandibular Mandibular From…
The super class Gnathostomata includes craniates, in which one pair of the visceral arches is modified into this jaws. They how internal ear with three semi-circular canals and provided with paired 4, apdages (fins or limbs). Sexes are separate. The super class is divided into, two groups. 1) Pisces…
Fishes are first evolved in silurian period of palaeozoic era. They increased their number in Devonian period. Devonian Period is Called Age of Fishes. Fishes are first jawed vertebrates. They live in water. They are cold blooded vertebrates. CHARACTERS Fishes are aquatic; cold blooded vertebrates. Their body…
Ammocoetes Larvae: Matamorphosis In the life history of Petromyzon a larval form is seen. It is called Ammocoetes larva. Ammocoetes larva is transparent and 1 cm., in length. Ammocoetes larva lives in U shaped burrows of mud. Ammocoetes larva comes out of the burrow at night only to…
Branchial Basket In Petromyzon the visceral skeleton contains branchial basket. It lies external to the gill pouches. It shows 9 irregular vertical bars and 4 longitudinal bars on either side. The first vertical bar lies just behind the styloid cartilage. The second is in front of the first gill…
Myxine (Hagfish) Petromyzon (Lamprey) 1. Hag fishes are scavengers. They penetrate into the dead fishes bodies and eat the tissues. 1. They are semi parasitic. But the Larvae(Ammocoetes) leads an independent life. 2. The body is. slender & eel-like 2. The body is cylindrical & stout. 3. They are exclusively…
The class Cyclostomata is divided into two orders:1) Petromyzonia and 2) Myxinoidea Order 1: Pefromyzonia Lampreys are included in this order. The buccal funnel is suctorial and shows horny teeth. The mouth is present in the buccal funnel. The nasal sac is dorsal. It has no connection with…
Cyclostomes’ are jawless vertebrates. They are primitive vertebrates. The cyclostomes are marine or fresh-water vertebrates. It includes the lampreys and hag fishes. The body is long, eel like. It shows trunk and compressed tail. Paired fins are absent. Median fin is supported by cartilaginous fin-rays. The skin Is…
SUB-PHYLUM VERTEBRATA is further divided into two super-classes. AGNATHA, AND GNATHOSTOMATA. SUPER-CLASS 1. AGNATHA: (A = Without; Gnathos = Jaw). Earlier vertebrates are included in it They do not show jaws, and paired appendages. Nostril is median and single. Ex: Petromyzon, Myxin. SUPER-CLASS 2. GNATHOSTOMATA:…
Vertebrates show the following characters, besides the chordate characters. 1. PRESENCE OF ENDO AND EXO-SKELETON: Vertebrates include internal skeleton which is a notochord or vertebral column. Vertebrates contain exoskeleton, made by scales or dermal plates etc. 2. CEPHALLZATLON: The vertebrates develop a head with brain and sense-organs. The…
LARVAE OF PORIFERA Parenchymula (Stereo- gastrula) - Leucosolenia Rhagon - Higher sponges Amphiblastula - Sycon Larvae of Porifera LARVAE OF COELENTERATA Planula - Obelia, Sea Anemone Ephyra - Aurelia (Jelly fish) Actinula - Some hydrozoan Anthocynathus - Coral fungia Conaria - Velella Hydratubia - Aurelia Planula - Obelia, Sea Anemone…
Most primitive primate Lemur Most primitive mollusc Chaetoderma Most primitive Arthropod Peripatus Most primitive Annelida Polygordius Most primitive fish Climatius Most primitive Helminth Planaria Most primitive reptile Sphenodon Most primitive Mammal Echidna Most primitive…
Allen’s Law – Allen Artificial Parthenogenesis – Loeb Axial Gradient theory – Child Bergman’s Rule – Bergman Biogenetic Law – Earnst Haeckel (1868) Biological Species Concept – Earnst Mayer Biogenesis Theory – Developed by F. Redi Chromosomal Theory of Inheritance – Sutton and Boveri Theory of natural selection – Charles…
Amino acid sequence of protein (insulin)Sanger Anaerobic release of energyL-Pasteur (1878) BacteriaLeeuwenhoek Pure culture of BacteriaLister J. BacteriophageTowrt and De Herelle (1915) Blood CapillariesMarcello Malpighi Blood GroupsKarl Landsteiner Blood CirculationWilliam Harvey BioluminescenceE.R. Dubois BiocatalystsBuchner CyanophageSaffermann and Morris First description of cell (RBC)Jan Swammerdam (1658) CellRobert Hooke (1665) Living cellA.V. Leeuwenhoek…