WHAT IS A VERTEBRATE? Animals with an internal skeleton made ofbone are called vertebrates. Vertebrates include fish, amphibians, reptiles,birds, mammals, primates, rodents andmarsupials
VERTEBRATES TRAITS The traits that makes them sospecial are the spinalcords, vertebrae, and notochords. Its all about having aseries of nerves along yourback (dorsal side). If you are anorganism, you cant just havethe nerves sitting there. Youneed to give those nervessupport and protection. Thatneed brings us to thebackbones and a rod ofcartilage called the notochord.
CLASS AGNATHA Agnatha is a group of vertebrates that lacks ajaw. The oldest fossil agnathans appeared inthe Cambrian, and two groups still survive today:the lampreys and the hagfish, comprising about120 species in total. Lampreys have a light sensitive pineal eye. Fertilization and development are both external.There is no parental care in the Agnatha class. The Agnatha are ectothermic or cold blooded, witha cartilaginous skeleton, and the heart contains 2chambers.LampetrafluviatilisAstraspis
CLASS CHONDRICHTHYE Also known as cartilaginous fishes arejawed fish with paired fins, paired nares, scales, aheart with its chambers in series, and skeletons madeof cartilage rather than bone. The class is divided into twosubclasses: Elasmobranchii (sharks, rays andskates) and Holocephali (chimaeras, sometimescalled ghost sharks, which are sometimes separatedinto their own class).Carcharodon
CLASS CHONDRICHTHYE The skeleton is cartilaginous. Their tough skin is covered with dermalteeth. All Chondrichthyes breathe through 5-7 gills, depending on the species. Fertilization is internal. Development isusually live birth (ovoviviparous species)but can be through eggs (oviparous).
CLASS OSTEICHTHYESEndocondral bonesform the skeletonEven and odd finsWith jaws, ussuallywith teethBreathing by gillsand covered by theoperculeSwim bladderCirculatory systemwith a heart, withatrium and ventriclewithout separationExcretory systemwith kidneysadapted to differentenvironmentsNervous system withsmall brain, olfatoryand optic lobes
CLASS AMPHIBIAResilient skeletalstructure with tetrapodappendixRespiratory system withlungs and a pair ofinternal nostrilsDouble circulation withpulmonary andsystemic, heart with 3chambersThe ear gets a timpanicmembraneThe cornea becomes theresponsible structure forlight refraction, theydeveloped eyelids andlacrimal glandules
MODERN AMPHIBIANSBone skeleton, with vertebraes, ribs, no exoskeleton.Great diversity of shapes and forms.2 pairs of extremities (tetrapods), with generally 4 fingers per anteriorlegSmooth and wet skin with many glandules.Normally big mouth, with small teeth in the superior jaw, 2 nostrils thatopen in the back of the mouth.Respiration by lungs and skin, independently or combined.Trichamber heart circulation.Ectothermics.Separated genders with internal fecundation in salamanders andexternal in frogs and toads.Oviparous, ovoviviparous and viviparous.