Biting mechanism of snake

A short note on Biting mechanism of snake:- The skull and jaw bones of poisonous snakes are very flexible. They are loosely articulated thus allowing a considerable degree of adjustment during the act of swallowing or striking. In cobras, the fangs are permanently erect. But in vipers the large fangs lie against the roof of mouth when closed. Thus the mechanism of biting serves two main purposes- a. Erection of fangs and b. Injection...

Read More

Poisonous apparatus in snakes

Poison apparatus includes-                 a. A pair of poison gland               b. Their ducts               c. Fangs and               d. Muscles a. Poison gland Two sac-like poison glands are situated one on either innerside of the upper jaw, below the eye. These are possibly...

Read More

DNA fingerprinting

A short idea about DNA fingerprinting DNA profiling or DNA fingerprinting is a sophisticated technique which is used often by experts which are helpful in identification of individuals by their respective DNA profiles. Some interesting salient features of DNA fingerprinting are: DNA fingerprinting is a technique to identify a person based on his/her DNA. DNA fingerprinting is specific to a person and it cannot be changed by any treatment. It is also known as genetic fingerprinting or DNA profiling. DNA fingerprinting is a very quick way...

Read More

AIDS

Acquired Immuno Deficiency Syndrome (AIDS): An Overview AIDS stands for Acquired Immuno Deficiency Syndrome, first described in 1981. AIDS is the result of damage of the immune system. A damaged immune system is unable to protect the body against certain specific, ‘opportunistic’ infections and tumours. These are called opportunistic because they are caused by organisms which are normally controlled by the immune system but which take the opportunity to cause disease if the immune system has been damaged.AIDS patients are sensitive to opportunistic...

Read More

Classification of Phylum Nematoda according to Ruppert & Barnes(1994)

Classification of Phylum Nematoda according to Ruppert & Barnes(1994) Phylum :- Nematoda Characters :- (i) They have perfectly cylindrical body adapted for living in minutes place. (ii) Body cavity is pseudocoel, Cuticle thick & tough. (iii) Circular muscle is absent, longitudinal muscles in 4 groups. (iv) Anterior end bear sense organ amphid & posterior phasmid present.  Class :- Aphasmida Characters :- (i) Anterior end of body bear chemo receptor amphids, phasmid absent posteriorly. (ii) Most are free...

Read More

Classification of Phylum Echinodermata

Classification of Phylum Echinodermata Phylum :- Echinodermata Characters :- (i) Adult with radial & five rayed symmetry, while the larvae are bilaterally symmetrical. (ii) The body is covered by calcareous ossicles or plates, often bearing projecting tubercles or spines. SubPhylum :- Crinozoa Characters :- (i) Madriporite absent. (ii) Radially symmetrical, possessing a cup shaped theca. Class :- Crinoidea Characters :- (i) Arms are branched & bearing pinnules. (ii) The ambulacral grooves radiates from...

Read More

Classification of Phylum Platyhelminthes

Classification of Phylum Platyhelminthes Phylum :- Platyhelminthes Characters :- (i) Body bilaterally symmetrical & dorsoventrally flattened. (ii) Digestive system had a single opening or mouth, that leads to a well developed gastrovascular cavity absent & anus absent. Class :- Tubellaria Characters :- (i) Turbellarian are mainly free living, aquatic, but there are some terristrial sp. (ii) Hermaphrodite, with internal fertilization. Example :- Planeria (free living) Class :- Trematoda Characters :- (i)...

Read More

Classification of Phylum Arthropoda

Classification of Phylum Arthropoda Phylum :- Arthropoda Characters :- (i) A pair of externally jointed appendages is usually present in each segment.(ii) Body is externally covered by thick, tough & chitinous cuticle, forming the exoskeleton. SubPhylum :- Crustacea Characters :-   (i) Head bears five pairs of appendages which comprises of two pairs of antennae & two pairs of   maxilla.  (ii) Respiration usually through gills. Class :- Branchiopoda Characters:-                            ...

Read More

Classification of Protozoa by Levine et al

Classification of Protozoa by Levine et al(1980) Subkingdom :- Protozoa Characters :- (i) They are usually microscopic & single celled animal & the single cells performs all the vital activities of the body. (ii) Body may be naked or covered by pellicle or enclosed in a shell. (iii) Main locomotory organs are pseudopodia, flagella or cilia (in sporozoa well define locomotory organs are absent). (iv) Nucleus single or multiple, which in sac like, oval or biconvex & contains a thick endosome. Phylum :- Sarcomastigophora Characters...

Read More