STRUCTURAL ORGANISATION OF ANIMALS
The variety in nature and habits of animals in the biosphere are quite amazing and interesting. What we see around us may be just few, but there are innumerable species living in this world. You have learnt in lower classes about the classification of animal kingdom. We will recall here that ‘Kingdom Animalia’ is divided into two groups, Invertebrates and Chordates.
There occurs a great diversity in the habit, habitat, structural organisation and mode of reproduction between the animals existing on earth. In this chapter, you will understand the structural morphology and anatomy of an Invertebrate (Leech) and a Vertebrate (Rabbit).
The scientific name of the Indian cattle leech is Hirudinaria granulosa which belongs to Phylum Annelida. Annelids are metamerically segmented worms with well developed organ systems.
The scientific name of the common rabbit is Oryctolagus cuniculus. It is represents Phylum Chordata and Class Mammalia. Mammals occupy the highest group in the animal kingdom and show advancement over the other groups of animals. They are warm blooded and possess covering of hair on the body. Mammary gland in females is the most striking feature of a mammal. Let us now study about the morphology of leech and rabbit in detail.