1. Deuterostome Phyla PHYLUM ECHINODERMATA: The phylum Echinodermata represents a relatively small group of unique, marine animals. The phylum contains starfish, sea cucumbers, sand dollars, sea urchins and brittle stars. They appear embryologically most closely related to the chordates but they have several features that set them apart. The echinoderms are all marine. They are all benthic organisms that are located in every ocean and at almost all depths. Some are active predators, others are scavengers and still others filter their food from the water.

2. 7. The coelom is extensive, involving the water vascular system and a large perivisceral cavity. 8. The circulatory and excretory systems are reduced or absent. 9. Respiration is by dermal branchiae or tube feet. 10. The nervous system consists of a nerve ring and 5 radial nerve cords. 11. Locomotion is by tube feet, spines or arm movement. 12. Sexes are separate, fertilization external and development involves a free-swimming, bilaterally symmetrical larva.

3. Phylum Characteristics: 1.Non-segmented animals with secondary pentaradial symmetry. The animals show no cephalization and no head or brain. 2. They are at the organ system level of organisation. 3. The echinoderms are enterocoelomic, triploblastic deuterostomes. 4. They have a complete digestive system. 5. They have an endoskeleton of dermal calcareous ossicles covered by an epidermis. 6. The echinoderms possess a water vascular system and tube feet.

5. PHYLUM CHORDATA These are the most familiar animals. This phylum includes the fishes, amphibians, reptiles, birds and mammals including humans. The structural plan on the chordates retains many of the features of the invertebrate animals. They are bilaterally symmetrical, triploblastic, coelomic, have an anteroposterior axis and cephalization.

6. They differ in having a completely different embryonic development, right from the zygote. The only invertebrates that show a sufficient kinship with the chordates to be considered an ancestor are the echinoderms. The radial indeterminate cleavage, the anus arising from the blastopore, and the enterocoelomic coelom formation all indicate a separate line of descent from the insects.

7. Like the arthropods, the chordates are an extremely successful group of animals. They also occupy almost all of the Earth's habitats. They compete with the insects at almost every ecological level. Unlike the invertebrates, there is a considerable likeness of form among the chordates.

8. Most of the primitive features of the phylum Chordata have only been modified to suit different (usually terrestrial) environments and not undergone extreme change. The phylum includes over 43,000 species grouped into three subphyla ( Urochordata, Cephalochordata, Vertebrata) The first two subphyla are small primitive organisms that live in a restricted marine environment. The remainder of the phylum, the subphylum Vertebrata contains over 98% of the animals.

9. Phylum Characteristics: 1. Multicellular, bilaterally symmetrical animals with an anteroposterior differentiation with segmentation. 2. Organ / system level of organization. 3. Triploblastic, enterocoelomic deuterostomial organisms. 4. Endoskeleton of cartilage and/or bone and a few with an exoskeleton. 5. Notochord present at some stage in the life. 6. Pharyngeal gill slits at some stage in the life. 7. Dorsal, hollow nerve cord. 8. A subpharygeal gland to concentrate iodine.

10. Vertebrata Characteristics: 8. Post-anal tail. 9. Jointed appendages. 10. Extracellular digestion in a complete digestive tract. 11. Closed circulatory system. 12. Excretion and osmoregulation through paired kidneys. 13. Respiration through skin, gills or lungs. 14. Reproduction only sexual and the organisms are dioecious.

11. The four distinctive traits that set the phylum Chordata apart from the rest of the animals. 1. Notochord flexible rod like support system; first part of the endoskeleton provides a site for muscle attachment in advanced chordates, replaced with the bony vertebral column 2. Dorsal, tubular nerve cord instead of the double ventral nerve cord of invertebrates system lies dorsally to the alimentary canal is hollow and enlarges into the brain at the anterior end

12. 3.Pharyngeal gill slits perforated, slit like openings that lead from the pharynx to the outside in primitive chordates, remain for life as the openings to the gills in higher fishes, undergo considerable embryological development in terrestrial forms they disappear in adult animals. 4.Subpharyngeal gland in early stages of development, all chordates have for concentrating iodine gland is homologous to the thyroid gland in humans.

14. Classification of the Chordates: phylum is divided into three subphyla division is unequal; few primitive aquatic marine forms in two subphyla vast majority in large subphylum Vertebrata Subphylum: Urochordata. tunicates

16. Subphylum: Cephalochordata. lancelets A lancelet technically, they are invertebrates because they lack bony structures; however, their bodies are supported by a gelatinous rod of tissue – a precursor to a backbone. small, transparent animals that spend most of their life partially buried in sandy burrows just below the low- tide zone they filter-feed, using the whiskery growths around their mouths to trap food