Bioniac

Classification of Animal Kingdom: This diagram showa the classification of Kingdom Animalia on the basis of factors discussed before Click  here for part-1 Click  here for part-2 Click here  for part-3 Click  here for part-4 Click  here for part-5

Segmentation Some animals have body externally and internally divided into segments with serial repetation of atleast some organs as shown in earthworm, where body shows metameric segmentation. This is metamerism Notochord It is a mesodermally origined  rod-like structure on dorsal side of embryonic development in some animal . Animals who have this structure are called chordates and those who don't are called non-chordates

Coelom Def.- Coelom is a cavity present between body wall and gut wall. It is lined by mesoderm      In the basis of presence and type of coelom, animals are classified into 3 types 1) Acoelomates: The animals in which body cavity is absent os called acoelomate e.g. Platyhelminthes 2)Pseudocoelomates: In some animals, body cavity is not lined by mesoderm. Instead, the mesoderm is present as scattered pouches in between ectoderm and endoderm. Such body cavity is called pseudocoelom and such the animals possessing them is called pseudocoelomate e.g. Aschelminthes  3)Coelomate: Animals that possess a body cavity lined by mesoderm are known as coelomate e.g. Annelids to Chordates Types of animal on the basis of coelom structure a)Coelomate b)Pseudocoelomate c)Acoelomate

Body Organisation Animals have three germinal layers of cell in their embryonic stage. Those layers are called Ectoderm , Endoderm and Meroderm . On the basis of presence of mesoderm or middle layer, animals are divided into two  categories- • Diploblastic: Animals that have only two embryonic layers are called diploblastic body organisation. They lac the mesoderm layer. An undifferentiated layer called mesoglea is present instead of mesoderm e.g. Coelenterates • Triploblastic: Animal that have all three embryonic layers are called to have triploblastic body organisation. Mesoderm is present in between Ectoderm and Endoderm. e.g. Platyhelminthes to Chordates   Body organisation (Germinal layers) (a) Diploblastic (b) Triploblastic Click  here  for part 1 of this chapter Click  here  for part 2 of this chapter

Symmetry • Asymmetrical: Any plane that passes through the center doesn't divide the following organism into two equal half e.g. sponges • Radial Symmetry: Any plane that passes through the central axis of the body divides the following organism into two equal halves e.g.   Coelenterates , Ctenophores, Adult Echinoderms      Radial Symmetry( Hydra sp. ) • Bilateral Symmetry: The body of the following organism can be divided into two equal halves if and only if the cutting plane pass through in a particular way through central axis e.g. Annelids , Arthropods etc. Bilateral Symmetry( Brachyura sp.) Click  Here  for part 1 of this chapter

Basis of Classification: Levels of Organisation *All members of Kingdom Animalia is multicellular •Cellular Level of Organisation:   1) Cells are arranged as loose aggregates   2) Some division of labour occur among the cells e.g. Sponges •Tissue Level of Organisation: 1) Cells performing the same function are arranged intotossues e.g. Coelenterates •Organ Level of Organisation: 1) Tissues are grouped together to form organs, each specialised for a particular function e.g. Platyhelminthes •Organ System Level of Organisation: 1) Organs have associated to form functional systems, each system concerned with specific physiological function  e.g. Annelids to Chordates Types in case of Organ System Level of Organisation: •Incomplete Digestive System:      Possess only one single opening outside the body which act as both mouth and anus e.g. Platyhelminthes •  Complete Digestive System:     Possess two openings • Open Type Circulatory System: ...