The sub-phylum Cephalochordata includes a single class Leptocardii, which has single family, Branchiostomidae. The family contains only two genera Branchiostoma and Asymmetron.   The subphylum - Cephalochordata includes Amphioxus or…
Cephalochordata includes two genera, 1. Asymmetron and 2. Branchiostoma (Amphioxus). Cephalochordates are small fish like animals which show Chordate characters. The notochord extends the entire length of the body. They…
Phylum Chordate is divided into three Sub-Phyla.   SUB-PHYLUM: UROCHORDATA SUB-PHYLUM: CEPHALOCHORDATA SUB-PHYLUM: VERTEBRATA   The first two sub phyla are called lower chordates or PROTOCHORDATES. They are usually called…
CHORDATES   The Phylum Chordate includes bilaterally symmetrical, metamerically segmented, triploblastic, enterocoelomate metazoans exhibiting hights complex organization. This phylum is supposed to be one of the most heterogenous and diversified…
The animal kingdom is divided into two sub-kingdoms:   Chordata Non-Chordata   GENERAL CHARACTRS OF CHORDATES   The Chordate characters appear in the developmental stage will persist in the adult…
THEORIES ABOUT ORIGIN OF CHORDATES   It is believed that Chordates have originated from invertebrates. It is difficult to determine from which invertebrate group the chordates were developed. Chordate ancestors…
In Eutherian mammals the embryo develops in the uterus of mother. The developing embryo will get nourishment from mother through the placenta. Placenta is not common to all mammals. It…
There is an interrelation between the form of teeth arid nature of food. These may be omnivorous, carnivorous, insectivorous herbivorous and rodents or gnawing. In Mammals dentition is complete in…
The tooth develops partly from the epidermis and partly from the mesenchyme of dermis. Its enamel is derived from the epidermis and the remaining parts from the mesenchyme. Mammalian teeth…
Two main theories have been proposed to explain the evolution of molars.   CONCRESCENCE THEORY OF ROSE TRLTUBERCULAR THEORY OF COPE & OSBORN According to the concrescence theory, the molar…

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