CHONDRICHTHYES CLASS, VERTEBRATA

*they are marine animals with streamlined body.
*they have cartilaginous endoskeleton
*mouth is located ventrally
*notochord is persistent throughout life
*gills slit are separate and without operculum(gills cover)
*skin is tough and have placoid scales
*teeth are modified placoid,and very strong jaws
*they lack air bladder, hence the have to swim constantly
*heart is two chambered
*some of them have electric organ
*some possess poison sting
*they are cold blooded.
*sexes are separate
*fertilization is internal

*e.g.-Scoliodon, Prestis,Trygon

CYCLOSTOMATA CLASS, VERTEBRATA

*habitat- fresh water and marine water.
*mouth is jawless and they are called jawless fishes.
*body is eel like and tail is compressed
*skin is soft and scale less
*head and brain is poorly developed
*unpaired fins are present
*paired fins and associated girdles are absent
*endoskeleton is cartilaginous
*stomach is absent.
*respiratory organs are gills
*heart is two chambered
*there are 10 or 8 pairs of cranial nerves
*lateral line sense organs are present
*fertilization is external.
*they are mostly parasite on some fishes
*e.g.-Lamprey, Hag fish

CHORDATA PHYLUM

*presence of eal gilnotochord, dorsal hollow nerve cord and paired pharyngeal gill slit are the characterised feature of chotdata.
*habitat- found everywhere
*symmetry- bilateral
*body form- triploblastic
*body cavity- coetomate
*level of organisation-organ system level
*circulatory system- closed type
* phylum chordata is divided into three subphylua-

1. Urochordata /Tunicata
2. Cephalochordata
3. Vertebrata 

*Urochordata and Cephalochordata are comes under protochordates.
*protochordates are exclusively  marine.
*in urochordata the notochord is present only in larval tail.
*in cephalochordata , notochord  extends from head to tail region, throughout life
*e.g.-Urochordata-Ascidia, Salpa,Doliolum
         Cephalochordata-Branchiostoma
*in vertibrata the notochord is replaced by a cartilaginous or bony vertebral column. thus all vertibrates are chordates but all chordates are not vertebrates.

ASCIDIA

BRANCHIOSTOMA 

HEMICHORDATA PHYLUM

*habitat-lives in borrow and are exclusively marine
*body form-soft body and divided into proboscis,collar and trunk
*germ layer-triploblastic
*level of organisation- organ system level
*body wall-single layered epidermis
*coelom-enterocoelous
*digestive tract- it is complete
*gills slit- gills are present
*blood vascular system-open type
*excretory organ-glomerulus
*nervous system-primitive type, consists of nerve plexus
*sense organ-sensory cells are present on epidermis
*reproduction-mostly sexual
*development- except some most of them have indirect development
*e.g.- Balanoglossus, Rhabdopleura

BALANOGLOSSUS

RHABDOPLEURA

ECHINODERMATA PHYLUM

*habitat-all are marine
*body form-unsegmented, star shaped, spherical or cylindrical.
*spine and pedicellariae- many echinoderm bear spine pincer like pedicellariae.
*symmetry-bilateral in larvae and  pentamerous in adults.
*germ layer-triploblastic
*level of organisation-organ system level
*body wall-epidermis is single layered and ciliated
*body cavity-enterocoelic coelom
*ambulacral system( water vascular system)-presence of ambulacral system is the characteristic feature of phylum echinodermata.
*digestive tract-incomplete digestive tract
*respiratory organ-dermal or papulae, peristominal gills, genital bursae.
*excretory organ- excretion through diffusion
*nervous system-it consists of nerve ring
*sexes and fertilization-generally sexes are separate,fertilization is external
*development- indirect.

*classification-

1. Asteroidea-Asterias
2. Ophiuroidea-Ophiothrix
3. Echinoidea-Echinus
4. Holothuroidea-Cucumaria
5. Crinoidea-Antedon

ARTHROPODA PHYLUM

* habitat-land, soil, fresh water, sea water and as parasite on animal and plant body.
*body form-body is segmented externally.
*symmetry-bilateral symmetry
*germ layer-triploblastic
*level of organisation-organ system level
*body wall- exoskeleton is formed by cuticle
*body cavity-cavity filled with blood
*digestive tract-complete system , alimentary canal consists of stomodaeum (fore gut), mesenteron (mid gut) and proctodaeum (hind gut)
* blood vascular system- it is of open type.
* respiratory organ-gills or book gills in aquatic forms, tracheae or book tracheae in terresterial forms, in some arthropods exchange of gases also takes place through skin.
*excretory organ-the excretory organ are either green gland or malpighian tubules . in some forms coxal gland are excretory organ.
*nervous system- nerve rings are present.
*sexes-sexes are separate.
*development- it may show metamorphosis.
*various classes of arthropoda are-

1. Crustacea-Palaemon (prawn), Palinurus( lobester), Lucifer
2. Chilopoda- Scolopendra
3. Diplopoda-Julus
4. Insecta-silver fish, cockroach
5. Archnida-scorpion, spider, tick
6. Onychophora-Peripatus
7. Merostomata-Limulus

PRAWN

SCOLOPENDRA

JULUS